Categories
Emergency Department Intensive Care Unit Medical Education

Clinical Interpretation Of Arterial Blood Gases

In the previous post, the physiology of the acid-base system was discussed. This post will focus on the practical interpretation of arterial blood gases for clinical diagnosis. The arterial blood gas (ABG) is usually the quickest lab test to obtain in a critically ill patient. In the emergency department, in the ICU, in the operating room, and during cardiopulmonary resuscitation, the ABG often leads to a correct diagnosis and directs initial treatment. There are four steps in interpreting the acid-base components of an ABG:

  1. Determine if the primary process is an acidosis or alkalosis
  2. Determine if the primary process is respiratory or metabolic
  3. Determine if the primary process is appropriately compensated
  4. Check the anion gap

This post will focus on the acid-base components of the ABG and will not discuss oxygenation.

Steps 1 &2: Determine the main acid-base disorder

Although normal values for pH, PCO2, and HCO3 are in reality a range, it is much easier to assume a single normal numeric values for each when interpreting an acid-base disturbance. Therefore, assume normal values of:

  • pH = 7.40
  • PCO2 = 40
  • HCO3 = 24

If the ABG shows a pH < 7.40,  then there is an acidosis; if the PCO2 is elevated, then it is a respiratory acidosis and if the HCO3 is reduced, then it is a metabolic acidosis.

On the other hand, if the ABG shows a pH > 7.40, then there is an alkalosis; if the PCO2 is reduced, then it is a respiratory alkalosis and if the HCO3 is elevated, then it is a metabolic alkalosis. Therefore, each of the four primary acid-base disturbances can be defined as follows:

Respiratory Acidoses:

Respiratory acidoses can be divided into those that are acute (duration of minutes to hours) and those that are chronic (duration of days, weeks, or years). The patient’s clinical history will dictate whether the condition is acute or chronic. For example, a newly unconscious patient with a fentanyl ingestion 45 minutes ago will typically have an acute respiratory acidosis whereas a smoker with long-standing, stable COPD will typically have a chronic respiratory acidosis. There are six main causes of respiratory acidosis:

Respiratory Alkalosis:

Respiratory alkaloses can also be divided into those that are acute and those that are chronic. Once again, the patient’s clinical history will dictate whether the condition is acute or chronic. There are eight main causes of a respiratory alkalosis:

Metabolic Acidoses:

There are two subcategories of metabolic acidosis: (1) increased anion gap metabolic acidosis and (2) normal anion gap metabolic acidosis. The anion gap can be calculated using the equation:

Anion Gap = Na – (Cl + HCO3)

The anion gap is normally composed of miscellaneous anionic molecules in the blood such as albumin and phosphate. When the anion gap is increased, then there are abnormal anions in the blood that will result in a lowering of the HCO3 level. The anion gap is often reported from the lab when ordering an electrolyte panel but for general ABG calculation purposes, a normal value of up to 12 mEq/L can be assumed (normal range = 6-12 mEq). However, when the pH is very high (> 7.50), the anion gap will increase to 15-16 by uncovering anionic sites on albumin. Therefore, a slightly elevated anion gap is normal when the pH is very high. The anion gap can be decreased in conditions such as hypoproteinemia, hypophosphatemia, and multiple myeloma (the latter due to an increase in cationic monoclonal IgG levels).

There are five common causes of an increased anion gap metabolic acidosis and two common causes of a normal anion gap metabolic acidosis:

Note that aspirin overdose can cause both a respiratory alkalosis (by direct stimulation of the brain’s respiratory drive center) and a metabolic acidosis (by accumulation of acetylsalicylic acid in the blood).

Increased anion gap metabolic acidoses can be further subdivided into those that cause an increased osmolar gap (> 10 mOsm/L) and those with a normal osmolar gap (< 10 mOsm/L). The osmolar gap is the difference between the measured and the calculated osmolality of the blood and this is normally reported out by the lab when a plasma osmolality test is ordered. The two most common causes of an increased osmolar gap are (1) methanol poisoning and (2) ethylene glycol poisoning. These are critical diagnoses to make because neither ethylene glycol nor methanol blood levels are able to measured quickly and so the arterial blood gas is usually the only way to establish an early diagnosis in order to direct life-saving treatment. All of the other causes of metabolic acidosis result in a normal osmolar gap.

Metabolic Alkaloses:

There are two subcategories of metabolic alkalosis: (1) chloride responsive metabolic alkaloses and (2) chloride unresponsive metabolic alkaloses. Chloride responsiveness is defined by the urine chloride level: if the urine chloride is < 10 mEq/L, the metabolic alkalosis is chloride responsive and if the urine chloride is > 10 mEq/L, the metabolic alkalosis is chloride unresponsive. There are three common causes of a chloride responsive metabolic alkalosis. Although there are also three causes of a chloride unresponsive metabolic alkalosis listed below, the most common is corticosteroid medication.

Step 3: Determine if the main acid-base disturbance is compensated

Very frequently, there will be more than once acid-base disturbance simultaneously. For example, a patient with pneumonia can have both a respiratory acidosis (from respiratory failure) and a metabolic acidosis (from lactic acidosis due to sepsis). To determine if there is more than than one acid-base disturbance, there are compensation rules. If a patient meets the criteria for these rules, then there is a simple acid-base disturbance (i.e., only one acid-base disturbance). Many of these rules are cumbersome and involve using nomograms or complex formulas. The following are the compensation rules that I have used throughout my career that are simple, require minimal calculations, and easy to use:

  • Metabolic acidosis: The last 2 digits of the pH will equal the PCO2
  • Metabolic alkalosis: For every 10 mEq increase in the HCO3, there will be a 6 mm increase in the PCO2
  • Respiratory acidosis:
    • Acute: For every 10 mm increase in the PCO2, there will be a 1 mEq increase in the HCO3
    • Chronic: For every 10 mm increase in the PCO2, there will be a 3.5 mEq increase in the HCO3
  • Respiratory alkalosis:
    • Acute: For every 10 mm decrease in the PCO2, there will be a 2 mEq decrease in the HCO3
    • Chronic: For every 10 mm decrease in the PCO2, there will be a 5 mEq decrease in the HCO3

If the patient fails the simple acid-base disorder compensation rule, then there is more than one acid-base disturbance. The direction of change from the expected compensation in PCO2 (metabolic disorders) or HCO3 (respiratory disorders) will indicate what that second acid-base disorder is.

Although patients can rarely have three or even four different acid-base disorders occurring at the same time, most patients will only have one or have two occurring simultaneously. The table below describes the findings when there are two acid base disturbances:

Step 4: Check the anion gap

Always, always, always calculate the anion gap! If the anion gap is elevated, then there is an increased anion gap metabolic acidosis, even if the pH, PCO2, and HCO3 are all normal.  The combination of a metabolic acidosis plus a metabolic alkalosis can cause the ABG to appear normal and the only clue that the patient has acid base disorders will be the increased anion gap.

The “delta-delta” rule. The Greek letter delta (Δ)is often used in medical shorthand to mean ‘change in’. In a simple, compensated increased anion gap metabolic acidosis, the Δ anion gap should always be equal to the Δ bicarbonate. In other words, the increase in the anion gap in mEq/L from normal should equal the decrease in the HCO3 in mEq/L from normal. Once again, assume that the normal anion gap is 12 mEq/L and the normal HCO3 is 24 mEq/L. If these two values for Δ are not equal, then there is a second acid-base disturbance. For example, if the anion gap is 20 mEq/L (8 mEq/L above normal), then the bicarbonate should be 16 mEq (8 mEq/L below normal). If the change in bicarbonate is larger than the change in the anion gap, then there is a concurrent metabolic acidosis. On the other hand, if the change in bicarbonate is smaller than the change in anion gap, then there is a concurrent metabolic alkalosis.

Questions containing a completely normal ABG with an increased anion gap are a favorite of those who write questions for board examinations, and with good reason. A common scenario where this occurs is the patient with diabetic ketoacidosis (causing an increased anion gap metabolic acidosis) who is vomiting (causing a chloride responsive metabolic alkalosis). In this case, the decrease in the HCO3 from the metabolic acidosis can be offset by the increase in the HCO3 from the metabolic alkalosis – the ABG can look normal but the patient will still be very sick. The Δ bicarbonate will be less than the Δ anion gap. In this situation, the increased anion gap will be the only prompt for the emergency room physician to immediately start the patient on IV fluids and insulin.

There is a wealth of information contained in those four numbers: the pH, PCO2, HCO3, and anion gap. During emergent situations, such as during a cardiopulmonary arrest, there is not time to look up ABG interpretation in a book or on-line reference. By being able to rapidly analyze the acid-base status, the clinician can use that information to direct life-saving treatments. Memorization of the differential diagnosis of each of the four primary acid-base disturbances and memorization of the compensation rules is essential to the practice of emergency medicine, anesthesia, and critical care medicine.

May 9, 2022

Categories
Emergency Department Intensive Care Unit Medical Education

Physiology Of Arterial Blood Gases

Part 1 of this post will cover the physiology behind arterial blood gases and part 2 will cover clinical interpretation of arterial blood gases. Arterial blood gases (ABGs) are an essential part of the evaluation of unstable patients. In unconscious patients who are unable to give a history, the blood gas can provide key data that can lead to a diagnosis long before other test results come back. In the intensive care unit and in the operating room, the ABG can provide critical results that can direct life-saving treatment. But optimal use of the arterial blood gas requires the physician to be able to rapidly interpret the results of the ABG. The two main components of the arterial blood gas are (1) oxygenation and (2) acid-base status. This post will focus on the background physiology of the acid-base components of the ABG. If you are primarily interested in the use of ABGs in clinical decision making of acid-base disorders, skip ahead to the next post.

Components of the ABG

Fundamentally, there are 5 main results in an arterial blood gas report: pH, PO2, PCO2, HCO3, and O2%. The pH is measured directly and indicates whether the patient is acidemic (pH < 7.40) or alkalemic (pH > 7.40). The PO2 is the partial pressure of dissolved oxygen in the blood. The PCO2 is the partial pressure of dissolved carbon dioxide in the blood. The HCO3 is the bicarbonate concentration which is very similar to the serum CO2 reported in an electrolyte panel (the serum CO2 is the total of everything that can be converted into CO2 in the blood including bicarbonate, carbonic acid, and dissolved carbon dioxide – it should not be confused with the PCO2 from the arterial blood gas which is a completely different value). The O2% is the oxygen saturation which is the percentage of hemoglobin binding sites that contain bound oxygen molecules. The normal values for each of these results are usually listed as a range of normal but for the purposes of analyzing the acid-base status, consider normal to be single numbers: pH = 7.40, PCO2 = 40 mm Hg, and HCO3 = 24 mEq/L.

Many ABG analyzer machines can also measure other values such as methemoglobin, carboxyhemoglobin, potassium, lactate, hemoglobin, etc. However, these tests usually need to be ordered separately and if only an ABG is ordered, then you will just get the 5 results as described above.

Acid-base regulation

Our bodies try to keep the pH as close to 7.40 as possible. The two ways that we regulate the pH are by (1) increasing or decreasing carbon dioxide excretion by the lungs and (2) increasing or decreasing bicarbonate excretion by the kidneys. When the carbon dioxide level of the blood is too high or too low, the kidneys compensate by increasing or decreasing the bicarbonate level of the blood by altering bicarbonate excretion in the urine. On the other hand, when the bicarbonate level is too high or too low, the lungs compensate by increasing the carbon dioxide level using hypoventilation or by decreasing the carbon dioxide level using hyperventilation.

Our tissues are constantly producing acids (in the form of hydrogen ions) and acid production can increase very rapidly with exercise. Therefore, there has to be an efficient way to get rid of acid as quickly as it is produced. This is done by converting hydrogen ions into carbon dioxide. In the blood, this is done by the enzyme carbonic anhydrase that first converts hydrogen ions into carbonic acid and then converts carbonic acid into carbon dioxide and water. The carbon dioxide is then excreted by the lungs in the form of exhaled carbon dioxide. When more acid (and thus carbon dioxide) is produced, for example, during exercise, the lungs can immediately dispose of that carbon dioxide by hyperventilation. In order to keep the pH at 7.40, we have to maintain a constant ratio of bicarbonate:dissolved carbon dioxide, as dictated by the Henderson-Hassalbach equation.

During conditions resulting in hyperventilation, the lungs get rid of more carbon dioxide and as a consequence, the blood PCO2 can become lower. Conversely, during conditions resulting in hypoventilation, the lungs are not able to get rid of carbon dioxide adequately and the blood PCO2 will rise.

There are other acids that are produced by metabolism that cannot be converted into carbon dioxide. These are called non-volatile acids and must be excreted by the kidneys. The kidneys can also excrete bicarbonate into the urine and can thus respond to a change in the blood carbon dioxide level by either eliminating or retaining bicarbonate. Unlike the lungs which can respond to increased carbon dioxide within seconds, it takes the kidneys 2-3 days to raise or lower bicarbonate levels with the result that the kidney’s full compensatory response to an acid-base disorder takes several days. However, the blood does have the ability to have a small but immediate effect on a changing carbon dioxide level by a chemical buffering mechanism. The result of this is that there are two responses to a high or a low carbon dioxide level: an acute compensation by chemical buffering and a chronic compensation from excretion of bicarbonate by the kidney. The buffering mechanism of the blood is fairly limited and can only result in a mild/limited degree of compensation compared to kidney excretion of bicarbonate.

Base deficit and base excess

In some situations, the ABG report will be resulted as “base deficit” or “base excess”. This is commonly used in the operating room by anesthesiologists. A base deficit refers to the amount that the bicarbonate level is too low and a base excess refers to the amount that the bicarbonate is too high. For practical purposes, base excess can be used synonymously with metabolic alkalosis and base deficit can be used synonymously with metabolic acidosis.

Acid-base disorders

Acid-base disorders can be divided into those that make the pH go up (alkaloses) or make the pH go down (acidosis). Each of these can be dividing into respiratory disorders that affect the carbon dioxide level and metabolic disorders that affect the bicarbonate level. Thus, there are 4 main groups of acid-based disturbances:

In a respiratory acidosis, the primary problem is that the blood carbon dioxide level is too high and the kidneys compensate by retaining bicarbonate. In a respiratory alkalosis, the primary problem is that the blood carbon dioxide level is too low and the kidneys compensate by increasing bicarbonate excretion into the urine. In a metabolic acidosis, the primary problem is that the blood bicarbonate level is too low and the lungs compensate by hyperventilating to reduce the blood carbon dioxide level. In a metabolic alkalosis, the primary problem is that the blood bicarbonate level is too high and the lungs compensate by hypoventilating to increase the blood carbon dioxide level.

As noted previously, the lungs can compensate to a metabolic acidosis or alkalosis within seconds but the kidneys take 2-3 days to fully compensate for a respiratory acidosis or alkalosis. However, there is a partial compensation to a respiratory acidosis or alkalosis by the buffering chemistry within the blood that happens immediately. For this reason, metabolic acidoses and alkaloses can be divided into those that are acute (occurring in minutes to hours) that are partially compensated by buffering and those that are chronic (occurring more than 2-3 days previously) that are more fully compensated by renal bicarbonate excretion.

It is important to note that a person can have more than one acid base disturbance at the same time. For example, a person can have a condition causing a metabolic acidosis and also simultaneously have another condition causing a metabolic alkalosis. Or, a person can have both a metabolic acidosis and simultaneously have a  respiratory acidosis. If there is a single acid-base disturbance, it is called a simple acid base disorder and if there are more than one acid-base disturbances, it is called a complex acid base disorder.

The next post will review the causes of acid-base disturbances and how interpretation of the arterial blood gas can be used to diagnose these disorders.

May 9, 2022

Categories
Medical Education

The Last Webcast

After 860 shows, I filmed my last continuing medical education webcast 2 weeks ago and today, it is being released on the internet. In 1998, I took over as moderator and editor of the weekly Ohio Medical Education Network TV series (OMEN-TV) that later became the webcast, OSU MedNet. For 24 years, I have spent every Friday at noon from September through June in a television studio to keep practicing physicians up to date on the newest developments in medicine. Today, I am now officially retired from the Ohio State University.

The third pillar of medical education

MedNet is devoted to continuing medical education (CME). There are three components to medical education: medical student education, graduate medical education, and continuing medical education. Medical student education is based in our nation’s medical schools where medical students receive 4 years of classroom and clinical education in order to receive their MD or DO degrees. Graduate medical education (GME) is based in our nation’s hospitals where graduates of medical schools spend 3-5 years training as residents and then may spend an additional 1-4 years training as subspecialty fellows. Continuing medical education is for physicians who have finished residency and fellowship training and are now out in clinical practice.

CME is the least lauded of these three pillars of medical education. Medical student education is the realm of university professors and deans whose salaries come from tuition, endowments, and state government support. GME is the realm of clinician educators, department chairs, and division directors whose teaching income comes from Medicare education support and clinical revenue. Success in both medical student education and GME can be a foundation for academic physician career development and university promotion. On the other hand, CME often lacks the glamour of medical student and resident education. Success in CME rarely leads to university promotion and most CME educators do it voluntarily, without pay.

Where do doctors get CME?

In order to maintain their medical licenses, doctors are required to have a certain number of continuing medical education hours every year. The specific requirements vary from state to state; here in Ohio, the State Medical Board requires physicians to have 50 hours of CME every two years. In the past, most physicians would get their CME from a combination of hospital grand rounds and medical conferences. Hospital grand rounds are free and the attendees are mostly physicians who practice at that particular hospital. Large hospitals can recruit grand rounds speakers from their own medical staff who present their grand rounds lectures without getting paid; delivering a grand rounds lecture is considered part of one’s normal professional obligations. Smaller hospitals generally have to bring in outside grand rounds speakers who get paid an honorarium fee. Weekly outside speakers can be very expensive for hospitals and for many smaller hospitals, can be cost-prohibitive.

There are two main types of medical conferences: those sponsored by hospitals and those sponsored by national specialty societies. Hospital-sponsored conferences are usually 1-day events that attract local or regional physicians and consist of several lectures on a particular topic, for example diabetes or heart disease. Specialty society-sponsored conferences are held once a year in a convention center and features dozens of lectures over several days that attendees can choose from. Conferences are very expensive to put on and the money to fund conferences comes from a combination of meeting registration fees and educational grants from pharmaceutical and medical devices companies. Like hospital grand rounds speakers, the educators at conferences generally do not get paid for delivering their lectures but sometimes have their meeting registration fees waived in exchange for their presentations.

A different way of doing CME

The Ohio State University was originally established as a land grant college. The land grant concept was created by the Morrill Act signed by Abraham Lincoln in 1862 that allowed the U.S. government to grant some colleges federal land to build on and in exchange, those colleges would focus on science, agriculture, and engineering (in contrast to private colleges that were largely based on liberal arts). Every state in the U.S. has at least one land grant college. One of the provisions of the Morrill Act was that land grant colleges also had to serve as a community resource for agriculture and science. This was the origin of agricultural extension offices that are still in use today.

In 1962, as part of its land grant mission, the Ohio State University created a medical education outreach program that had a lot of similarities to the agricultural extension offices. The program was called OMEN which stood for the Ohio Medical Education Network. It was broadcast at noon from an audio studio set up in Starling Loving Hall on the OSU Medical Center campus. Participating hospitals would be pre-mailed 35 mm Kodachrome slide sets and then OSU medical school faculty would broadcast their lectures over a telephone speaker system with “beeps” indicating when to advance the slides. After each formal presentation, the listeners could call in to get advice from the OSU specialists on the management of their own patients. Initially, most of the participating hospitals were smaller, often rural hospitals in Ohio. Over time, hospitals in other states and many VA hospitals were added. Sixty years ago, this was a revolutionary, state-of-the-art concept in distance education that for the first time, allowed physicians practicing in smaller communities to keep up with breakthroughs in disease diagnosis and treatment.

In 1990, OMEN expanded from the audio program using slide sets into a satellite TV program and was re-named OMEN-TV. The participating hospitals would use a satellite dish to receive the programs and they were filmed in a TV studio in Atwell Hall on the OSU Medical Center campus. The shows were live presentations and satellite time was rented from noon to 1:00 PM every Friday from September through June (mirroring the university’s academic year). The TV program had the advantage that now the audience could see the presenters and we could incorporate video, for example, of a surgical procedure. At the end of each show, viewers could call in and ask questions live on-air. In the early years of OMEN-TV, I was a frequent guest presenter, lecturing on various pulmonary and critical care topics. Then, in 1998, I took over as the moderator and medical editor of OMEN-TV.

Like its audio predecessor, OMEN-TV was a ground-breaking concept for continuing medical education. Initially, there was nothing else like it in the United States. Subscribing hospitals would pay a small annual subscription fee to the OSU College of Medicine and in return, they would get weekly medical education shows that allowed their doctors to get CME credits without having to leave to attend an out-of-town conference. It was also far less costly to the hospitals than bringing in outside grand rounds speakers every week. The downside was that if doctors were in the operating room or attending to sick patients at the time of the broadcast, they would miss the presentation. We did additionally replay the shows on cable TV but it was generally a public access channel and often shown at an inconvenient time of the day or night. The number of subscribing hospitals grew with more VA hospitals and community hospitals throughout the country added every year.

OMEN-TV was costly to produce. The live TV show required 3 cameramen, a sound technician, someone to hold cue cards (and later to run a teleprompter), staff to take viewer phone calls, a film director, computer technicians, a make-up artist, and a full-time producer. The subscription fees only covered a small part of the total production costs so additional financial support came from the OSU Medical Center. But even that was not enough to fully fund the program. So, we would reach out to pharmaceutical companies and educational foundations to get unrestricted educational grants. We would acknowledge these organizations in the credits at the beginning of each show, similar to what you see with PBS broadcasts. The hospital paid 10% of my salary to be the moderator and editor of OMEN-TV. Each show required about 8 hours of my time to recruit presenters, review and edit slides before broadcast, prep the presenters, rehearse, host the live show, and fill out all of the CME paperwork after each show. Each season initially consisted of 28 shows per year and we quickly expanded to 40 per year – every Friday from September through June with weeks off for major holidays. I was the sole host and the only times I could take vacations were July, August, and the weeks of Thanksgiving, Christmas, or New Years Day. Fortunately, I was able to avoid any major illnesses or injuries that would have kept me out of the studio.

But OMEN-TV had its downsides. Since it was a live broadcast, subscribing hospitals were limited to showing the program at noon on Fridays. We did not have a good way to reach physicians who were not on the medical staff of a subscribing hospital. Also, in the early 2000’s, there was mounting pressure from the Accreditation Council for Continuing Medical Education (ACCME) to eliminate educational grants from pharmaceutical companies in order to reduce the risk of conflict of interest affecting presentations. OMEN-TV needed to evolve once again into a leaner, more widely available program.

In 2002, OMEN-TV transformed from a satellite TV show into a webcast. In order to better reflect the internet medium of broadcast, the program was re-named OSU MedNet-21 (medical education for the 21st century). We retained most of the elements of the OMEN-TV production but now subscribing hospitals could show MedNet on any day and time that best fit with the hospitals’ medical staff calendars. Also, by being a video-on-demand product, we could keep the shows available on the internet for 3 years. So, at any given time, we had 120 hours of CME available on the OSU Center for Continuing Medical Education’s website. We made the webcasts available for free for anyone to view – no user account or password needed. The only requirement was that physicians who wanted to get CME credit for viewing the webcasts had to either view them at a subscribing hospital or had to pay a small fee after viewing the webcasts in order to take a 10-question CME post-test. The webcast format allowed us to track viewer numbers – we could not identify individual viewers but we could tell what country they were viewing from. We have had physician viewers from 136 countries watch MedNet webcasts. Soon after converting to a webcast, we moved production to the WOSU-TV studios on the university campus.

 

As a webcast, we were able to significantly reduce our production costs. In the WOSU-TV studio, we used 3 remotely operated digital cameras, eliminating the need for individual cameramen. We stopped using a make-up artist and since the webcasts were not shown live, we no longer needed people to operate phones. Instead of a massive studio crew, we were able to film each webcast using just 4 people in a separate control room to operate cameras, do audio, operate the teleprompter, and do the computer integration. With with reduction in production costs, we no longer needed grants from pharmaceutical companies and we were able to fully finance the program with subscription fees and support from the OSU Medical Center and the OSU James Cancer Hospital. Each webcast is also available as an audio-only podcast, allowing physicians to get their CME by podcast during their commute to and from work.

Meeting physician educational needs

Today, OSU MedNet goes out to 70 hospitals nationwide, with the largest number of subscribing hospitals here in Ohio. Because most of these hospitals are smaller community hospitals, most of the viewers are primary care physicians: family medicine, general internal medicine, pediatrics, and hospitalists. Each year, we do a needs assessment by soliciting topic recommendations from our viewers. We also ask the OSU department chairs, division directors, deans, and medical directors for topic suggestions. I would go through the last year’s editions of the New England Journal of Medicine, JAMA, and the Morbidity and Mortality Weekly Report from the CDC. From this, we had about 2-300 possible topics. We then use a group of OSU primary care physicians to rank the topics and the highest ranked topics become the next season’s shows. I then identify and recruit physicians from the Ohio State University to present each of those topics. For most of these presenters, it is the largest audience that they will ever have, reaching hundreds of physicians all over the world and impacting thousands of patients’ lives.

As a webcast, MedNet has the flexibility to do additional shows on short notice when new developments in medicine occur. So, for example, we were able to do webcasts on SARS, Ebola, and Zika virus within 2 weeks of the initial cases of these infections. When COVID-19 first developed in January 2020, we were able to put out a COVID-19 MedNet on February 3, 2020, just two weeks after the first reported case in the U.S. and before Ohio had any cases. Since the pandemic began, we have done 9 COVID webcasts as new developments in the diagnosis, treatment, and prevention arose. When case rates began to rise last winter due to the Omicron variant, we were able to get a COVID update on the internet within 5 days of concept inception in order to help physicians manage the surging number of cases in their own communities.

The last webcast

In April 2021, I retired from the Ohio State University and from clinical practice. I was at OSU for 43 years as a research lab assistant, medical student, resident, fellow, and professor. However, after retiring, I agreed to continue as the moderator and host of OSU MedNet until my successor was named. So, for the past year, I’ve continued to host the webcasts every Friday. I’ve done it as a volunteer, without compensation, because I’m very passionate about the program and about the need to continue to provide quality continuing medical education to physicians around the world. Besides, I have a lot of fun hosting the show and it has kept me engaged with the OSU medical community as a way of easing into retirement.

For two years, we recorded MedNet by Zoom from our office computers rather than using the WOSU-TV studios because of the COVID-19 pandemic. In March 2022, the case numbers had fallen low enough to permit us to take off our face masks and return to the studio safely. During the pandemic, construction did not stop on the new WOSU Media Building and last month, we filmed our first webcast in the new WOSU-TV studio. It is a truly state of the art facility with superior cameras, sound, and lighting.

It took nearly a year to solicit applications for the next MedNet moderator and then to select finalists, do auditions, and do the final selection. I am absolutely delighted that Dr. Shengyi (“Jing-Jing”) Mao will be taking over as my successor. She is an OSU primary care physician who is board certified in both internal medicine and pediatrics and has been a regular MedNet presenter in the past few years.

Today, we are releasing my last official webcast as moderator and host of OSU MedNet and next week, Jing-Jing will take over in the studio. I’ll be back occasionally to fill in when needed but for the first time in 24 years, my Fridays will be open and I’ll be free to travel outside of Columbus whenever I want. For my last show, I decided to be both the moderator and the guest and so I hosted my own presentation. I decided to talk about Physician Financial Health. For 15 years, I served as the treasurer and vice chair of the OSU Department of Internal Medicine and part of my responsibilities was to advise new faculty about retirement plan options, personal finances, and saving for children’ college education. That expanded to annual talks to the residents and the fellows about financial planning and has resulted in a number of posts on this blog about physician finances and about retirement planning. So, as a recent retiree, I decided that financial health would be a fitting topic for my last webcast. You can view the webcast by clicking here.

After 810 shows, I’ve learned a lot about areas of medicine that as a pulmonary and critical care physician, I never would have otherwise have learned about. I’ve met fascinating people who were our guests – both doctors and other healthcare professionals. I’ve also learned a lot about TV and webcast production. But most of all, I’ve had fun doing it… a lot of fun. And now, it’s time to become a MedNet viewer, rather than the MedNet moderator.

 

 

April 8, 2022

Categories
Academic Medicine Medical Education

Lessons From The 2022 Fellowship Match

This month, the National Resident Matching Program (NRMP) released the results of this year’s match for fellowships that will begin in July 2022. Match day for most subspecialty fellowships was in December 2021 although some subspecialties had their match day earlier in the year. The new report summarizes the results of these match days.

The process for physician training begins with medical school graduates entering a residency in a specific specialty such as internal medicine, pediatrics, obstetrics & gynecology, or surgery. After completing residency, physicians can do further subspecialty training in fellowships. For example, cardiology is a subspecialty of the specialty of internal medicine. Therefore, to become a cardiologist, a physician first completes an internal medicine residency and then completes a cardiology subspecialty fellowship. Some subspecialties have their own subspecialties. For example, a physician completing a cardiology subspecialty fellowship can go on to do an even more specialized subspecialty fellowship in cardiac electrophysiology.

In the match, physicians who are either in their final year of residency or have already completed residency apply to fellowship training programs. The physician applicants then rank the training programs in order of their preference and the fellowship training programs also rank the applicants in their order of preference. The NRMP computers then assign each applicant to a specific training program using an algorithm that matches the applicant’s preferences with the training programs’ preferences. Overall, the process works and ensures that the applicants get into their most preferred training program that will accept them.

Every spring, the NRMP releases an annual report of the data from the match and by examining the data, there is a wealth of conclusions about the current state of the various subspecialties.

More physicians are specializing

From 1995 to 2000, the number of fellowship positions as well as the number of physicians applying to fellowships fell. However, since 2000, there has been a steady increase in both the available fellowship positions as well as the number of applicants for those positions. This year, 13,586 physicians applied for 12,571 fellowship positions. The majority of applicants were U.S. MD degree graduates (7,141), followed by non-U.S. citizen graduates of international medical schools (2,619), U.S. DO degree graduates (1,991), and U.S. citizen graduates of international medical schools (1,791).

The number of fellowship positions has been increasing faster than the number of resident positions. Over the past 2 decades, resident positions have increased by 74% from approximately 20,200 in 2000 to 35,194 in 2021. During that same time period, fellowship positions have increased by 558%, from approximately 1,900 in 2000 to 12,571 in 2022. In other words, resident positions have not quite doubled in the past twenty years whereas fellowship positions have increased by 5.5-fold.

Internal medicine subspecialties account for the largest number of fellowship positions. 49% of the 12,571 fellowship positions were in internal medicine subspecialties, followed by pediatrics (14%), surgery (7%), and radiology (7%). The penetration of subspecialty fellowships varies between different specialties. For example, there were 1,137 resident positions offered in radiology in 2021 (the most recent year resident data is available) and 869 fellowship positions offered in radiology in 2022. Therefore, there were 0.76 radiology fellowship positions for every 1 radiology resident positions. If all resident and fellow positions were filled, then this would imply that 76% of radiology residents go on to do radiology subspecialty fellowships. Similarly, this analysis would estimate that 69% of internal medicine residents do fellowships whereas only 13% of physical medicine & rehabilitation residents do fellowships.

The number of foreign medical school graduate applicants fell

In recent years, the number of all types of applicants for subspecialty fellowships have been increasing. For the 2022 year, the number of non-U.S. citizens graduating from international medical schools (foreign medical graduates) decreased for the first time from 2,332 in 2021 to 2,280 in 2022. All other types of fellowship applicants increased in number in 2022. One of the main reasons for the decrease in foreign medical graduates was the COVID pandemic that resulted in immigration and travel restrictions that prevented many foreign applicants from coming to the U.S. for medical training.

Non-U.S. citizens who graduated from international medical schools make up a minority of physicians who match in most subspecialties. However, in subspecialties that are less popular with U.S. MD degree graduates, foreign medical graduates comprise the largest percentage of matched positions. Four subspecialties had more foreign medical graduates than U.S. MD degree graduates filling fellowship positions: adult endocrinology (40.4%), adult nephrology (35.8%), adult pulmonary (26.1%; note that there are relatively few positions available for adult pulmonary-alone fellowships and most positions are for combined pulmonary & critical care medicine), and medical genetics (52.2%).

U.S. DO degree graduates (osteopathic school graduates) have historically comprised the smallest number of subspecialty fellowship applicants but now exceed the number of applicants who are U.S. citizen graduates of foreign medical schools. Because of the traditional emphasis on musculoskeletal elements of disease and rehabilitation, osteopathic graduates tend to gravitate to certain subspecialties. Those with more than 20% of filled positions going to U.S. DO degree graduates include: pain medicine (21.5%), emergency medicine services (27.2%), global emergency medicine (22.7%), hospice & palliative medicine (20.7%), brain injury medicine (27.3%), spinal cord injury medicine (35.3%), and sports medicine (36.6%).

Highly competitive subspecialties

The more applicants (particularly U.S. MD degree graduates) there are per subspecialty fellowship position is a marker of how competitive that subspecialty is. Those subspecialties with more applicants than available fellowship positions are highly competitive whereas the subspecialties with more fellowship positions than applicants are less competitive. The 2022 NRMP fellowship match report reveals that some subspecialties are for more competitive than others. Overall, the average subspecialty fellowship filled with 51% U.S. MD degree graduates. The results listed below are the subspecialty fellowship positions that filled with more than 70% U.S. MD degree graduates:

  • Obstetrics & Gynecology. Overall, the subspecialties of OB-GYN are the most competitive of all major specialties: complex family planning (100%) filled all available positions with U.S. MD degree graduates followed by gynecologic oncology (94%), reproductive endocrinology (90%), maternal-fetal medicine (88%), pelvic & reconstructive surgery (79%), and minimally invasive gynecologic surgery (73%).
  • Surgery. Highly competitive subspecialties include: pediatric surgery (95%), hand surgery (85%), colon & rectal surgery (80%), and thoracic surgery (71%).
  • Pediatrics. Three of the 17 pediatric subspecialties were highly competitive: adolescent medicine (77%), child abuse (70%), and pediatric hospital medicine (70%).
  • Internal Medicine. Only hematology (85%) was highly competitive. However, relatively few physicians do a hematology-only fellowship (14 positions) and the vast majority do a combined hematology/oncology fellowship (663 positions).
  • Emergency Medicine. Medical toxicology (74%).

A second marker of competitiveness is the percentage of available fellowship positions in each subspecialty that fill with any applicant, including U.S. MD degree graduates, U.S. DO degree graduates, U.S. citizens graduating from international medical schools, and foreign medical graduates. Below are the subspecialties that filled more than 90% of their available fellowship positions:

Unpopular subspecialties

As in past years, some subspecialties are less popular. Those that filled with fewer than 40% U.S. MD degree graduates were mostly subspecialties of internal medicine and pediatrics:

  • Internal Medicine. The least competitive subspecialty was pulmonary disease (16%). However, relatively few physicians do a pulmonary-only fellowship (25 positions) and the vast majority do a combined pulmonary & critical care medicine fellowship (721 positions). Other unpopular subspecialties included nephrology (20%), geriatric medicine (20%), heart failure & heart transplant (27%), endocrinology (32%), infectious disease (38%), interventional pulmonary (38%), and oncology (38%). However, like hematology-only fellowships, there are relatively few positions in oncology-only fellowships (8) and most positions are in combined hematology & oncology (663) which was a considerably more popular subspecialty.
  • Pediatrics. The least popular pediatric subspecialty was infectious disease (20%) followed by developmental & behavioral pediatrics (29%), endocrinology (30%), and nephrology (32%).
  • Physical Medicine & Rehabilitation. Spinal cord injury medicine (32%).

Below are the subspecialties that filled fewer than 90% of there available positions with any applicant including U.S. MD degree graduates, U.S. DO degree graduates, U.S. citizens graduating from international medical schools, and foreign medical graduates:

Nephrology, endocrinology, and infectious disease remain unpopular

In both internal medicine and pediatrics, nephrology, endocrinology, and infectious disease are among the least popular subspecialties. One of the reasons that infectious disease and endocrinology remain unpopular is salary. According to the 2021 Medscape Physician Compensation Survey, the average general internal medicine physician had an income of $248,000 last year. However, despite requiring two additional years of subspecialty fellowship training after internal medicine residency, adult endocrinologists and infectious disease physicians made less than general internists at $245,000 for both subspecialties. It is difficult to justify investing two additional years into training in order to make less money than if you had gone straight into clinical practice after completing residency. A second physician salary survey is done by Doximity. Like the Medscape survey, Doximity also found that endocrinologists and infectious disease specialists have incomes less than general internists. In addition, the Doximity survey reports salaries for pediatric subspecialties and like their adult counterparts, pediatric endocrinologists and pediatric infectious disease specialists have a lower income than general pediatricians.

The Medscape survey also asks physicians if they feel they are adequately compensated – infectious disease physicians and endocrinologists are the least satisfied with their compensation at 44% and 50% of survey respondents satisfied respectively. The salary disparity has been particularly acute for infectious disease physicians who over the past two years of the COVID pandemic have been among the most over-worked physicians of any specialty. In other words, the message that internal medicine and pediatric residents hear is to go into infectious disease is to train longer, work harder, and get paid less.

The reasons for nephrology continuing to be unpopular are less clear. Nephrologists have a higher annual income than general internal medicine physicians with an average of $311,000 per year. However, this is less than other procedural internal medicine subspecialties such as pulmonary medicine, critical care medicine, cardiology, and gastroenterology. One of the primary clinical activities of nephrologists is overseeing dialysis. Most patients with end-stage renal disease receive hemodialysis three days per week, either Monday-Wednesday-Friday or Tuesday-Thursday- Saturday. Because of this schedule, nephrologists typically have a 6-day workweek to cover dialysis with a 1-day weekend (Sunday) whereas other subspecialties typically have a 5-day workweek with a 2-day weekend. It is possible that the longer workweek attendant to nephrology could be discouraging physicians from entering the subspecialty.

Geriatrics continues to be an unpopular subspecialty. Unlike many of the other fellowships, a physician can do either an internal medicine or a family medicine residency prior to a geriatric medicine fellowship. Salary is one of the barriers to applicants. Geriatric medicine requires a 1-year fellowship and most geriatricians practice primary care medicine for people over age 65. There is no additional compensation in terms of RVUs for caring for older patients and many of these patients have multiple concurrent medical problems as well as cognitive impairment. As a result, it can take a geriatrician longer for an outpatient visit while getting paid the same amount that a primary care internist or family physician would be paid for an office visit for a younger, less medically complex patient. Thus, the economics of geriatric medicine discourages family physicians and internists from entering the subspecialty.

So, what does all of this mean?

As fewer physicians go into specific subspecialties, there will likely be shortages of those subspecialists in the future. The pediatric subspecialties of endocrinology, infectious disease, and nephrology had a lowest percentage of available fellowship positions fill and will therefore face physician shortages in the near future. However, I believe that the most serious future shortage will be in adult nephrology. Pediatric subspecialists are relatively small in numbers and almost always located in large referral pediatric hospitals. On the other hand, adult nephrologists are needed in most community hospitals and any town large enough to have an outpatient dialysis center.

The number of unfilled subspecialty fellowship positions is even larger for geriatrics. However, general internal medicine physicians and family physicians can more easily fill in for shortages in geriatricians. Therefore, shortages of physicians trained in geriatrics will not be felt as severely by most communities.

For capitalism to work in medicine, supply and demand have to be unconstrained so that when the supply of a subspecialty falls, demand for that subspecialty can bring the supply back up through free market forces that increase the pay for those subspecialists. The U.S. system for paying physicians has led to an uncoupling of supply and demand. Unless health policy changes the way that subspecialists such as endocrinologists, infectious disease specialists, and nephrologists are compensated, we will be facing an increasing shortage of these physicians in the future. In the meantime, if your hospital has one of these subspecialists who is a high-performer, treat him or her well – they are becoming a very rare breed.

March 30, 2022

Categories
Medical Education Procedure Areas

How To Interpret Pulmonary Function Tests

Pulmonary function tests (PFTs) can be very intimidating. A PFT report has many different numbers and for the non-pulmonologist, it is often difficult to know which ones are important and what they mean. As a consequence, many non-pulmonologists just look at the computer-generated interpretation and ignore all of the numbers. The bad news is that the computer-generated PFT interpretations are woefully bad – the computer is pretty good at identifying normal but generally terrible at identifying degrees of abnormal. The good news is that PFT interpretation is actually very easy and in this post, I am going to show you everything you need to know to interpret 99% of the PFTs that you order by looking at just 5 numbers. There are fundamentally four components to a complete PFT: spirometry, lung volumes, diffusing capacity, and the flow-volume loop. We will next look at each of these components.

Spirometry

Spirometry is the most common PFT that you will order. It can either be performed by a respiratory therapist in a pulmonary function lab using an expensive PFT machine (> $50,000) or it can be performed by a nurse in an office setting using a portable spirometer (about $1,000). Spirometry is primarily a measurement of air flow and is used to determine whether or not a patient has obstructive lung disease.

You will see a lot of different numbers on a spirometry report but the only ones that are truly important are the forced vital capacity (FVC), the forced expiratory volume in the first second of exhalation (FEV1), and FEV1/FVC which is the ratio of these two numbers. The other numbers are of minimal importance and you can ignore them. The results of the FVC and FEV1 will be listed both as actual values (in liters of air) and as the percent of predicted. In order to determine the percent of predicted, researchers have measured the FEV1 and FVC of thousands of normal people to determine what a normal value is. “Normal” depends on a person’s age, height, gender, and race so it is important that these demographic elements are correctly entered into the PFT machine so that the computer in the machine picks out the correct normal value based on that patient’s age, height, race, and gender. If the patient’s FEV1 or FVC is lower than the 5th percentile of normals (lower limit of normal), then the PFT machine will flag the result – usually with a different color font or an asterisk by the number.

The ratio between these two numbers, the FEV1/FVC, tells you whether or not the patient is obstructed. If the FEV1/FVC is too low, the patient is obstructed and if the FEV1/FVC is either normal or higher than normal, then the patient is not obstructed.  There are 2 definitions of a “normal” FEV1/FVC that are commonly used. The first (and most common) is the definition used by the American Thoracic Society (ATS) – it is based on a patient’s age because the older we get, the lower a normal person’s FEV1/FVC becomes simply as a result of normal aging. The average FEV1/FVC for a 20-year-old is 87% whereas the average FEV1/FVC for an 84-year-old is 71% and the lower limit of normal for an 84-year-old is 59%. The computer in the PFT machine will flag the FEV1/FVC as being too low based on whatever age is entered in the patient demographics. The second definition of normal FEV1/FVC is used by the Global initiative for chronic Obstructive Lung Disease (GOLD) which uses a flat FEV1/FVC ratio of 70% as being normal for everyone and does not make any adjustments based on a person’s age. Almost all PFT machines will use the ATS method when generating a PFT report but Medicare requires the GOLD method when determining eligibility for enrollment in pulmonary rehabilitation.

If the FEV1/FVC ratio is low for the patient’s age, then the next step is to determine how obstructed they are. This is determined by how low the FEV1 is. IMPORTANT: if the FEV1/FVC ratio is normal, then it does not matter how low the FEV1 is since that patient is not obstructed. The severity of obstruction is usually based on the ATS criteria but once again, the GOLD criteria is different.

If a patient is found to have obstruction based on a low FEV1/FVC, then sometimes a bronchodilator study is performed by giving the patient an albuterol treatment and then repeating the spirometry a few minutes later. Reversible obstruction is defined as an increase in either the FEV1 or FVC by 12% after albuterol. In addition, the amount of the increase in FEV1 or FVC must be at least 200 ml to qualify as reversible obstruction. If the initial FEV1/FVC is normal, there is no point in doing a bronchodilator study.

For the spirometry test result to be accurate, three things must occur: (1) the patient’s age, race, height, and gender must be entered correctly, (2) the patient must be coached correctly by the nurse or respiratory therapist administering the test and the patient must give a good effort, and (3) the physician or advance practice provider must correctly interpret the test.

Steps in spirometry interpretation:

  1. Is the patient obstructed? This is determined by whether the FEV1/FVC ratio is low.
  2. If they are obstructed, how obstructed are they? This is determined by how low the FEV1 is below normal.
  3. If they are obstructed, is the obstruction reversible? This is determined by the amount of increase in the FEV1 and/or FVC after albuterol.

Lung Volumes

Lung volumes cannot be measured using an office spirometer and require testing in a pulmonary function laboratory. This is typically done by having a person sit in a plethysmographic box and performing a series of inhalation and exhalation maneuvers. Once again, the PFT machine will generate a whole bunch of numbers but the only one that is really important is the total lung capacity (TLC). If this number is too low, then the patient is restricted and if it is too high, then the patient is hyperinflated. Just as in spirometry, the TLC percent predicted is based on the patient’s age, height, race, and gender.

Of note, some office spirometry machines will give a computer-generated interpretation of restriction based on the FVC alone. You really cannot diagnose restriction using the FVC alone from spirometry, the diagnosis requires measuring the TLC with lung volumes – the FVC can sometimes be low when the TLC is totally normal. The finding of a low FVC on office spirometry should merely be an indication to send that patient to the pulmonary function lab for a complete set of PFTs that includes lung volume measurements.

If the TLC is larger than the upper limit of normal (generally around 120% of predicted), then the patient is hyperinflated. The only other number that is worth knowing about is the residual volume (RV). If the RV is too high (above the upper limit of normal), then the patient has air-trapping. Patients who are obstructed will often also have hyperinflation or air-trapping. In fact, isolated air-trapping alone can indicate early obstruction, even when the FEV1/FVC ratio is normal.

Diffusing Capacity

The DLCO is the “Diffusing capacity of the Lung for carbon monoxide (CO)”. This is measured by having the patient breath a tiny amount of carbon monoxide gas and then comparing the amount of carbon monoxide in the inhaled gas versus the amount in the exhaled gas. The difference indicates how much of the carbon monoxide was taken up by the body (the carbon monoxide binds to hemoglobin in the bloodstream). The more carbon monoxide is taken up, the easier it is for gases to get from the air a person breaths into the bloodstream. If the amount of carbon monoxide taken up is low, then this is a sign that gases cannot move normally from the lungs into the bloodstream.

The DLCO will be low in diseases such as emphysema and interstitial lung disease. However, the DLCO can also be low if the patient has small lung volumes for any reason. Because of this, the PFT machine will often report the DLCO/VA where the VA stands for “alveolar volume” and is more or less the same thing as the total lung capacity. The DLCO/VA is a better measurement of diffusing capacity in situations such as previous partial lung removal or restriction due to muscle weakness. The DLCO can also be low if the patient is anemic. For this reason, the PFT machine will often report the DLCOcor which is the DLCO corrected for the patient’s hemoglobin level. Whether to use the DLCO, the DLCO/VA, or DLCOcor is a matter of debate. Most of the time, you can just go by the DLCO unless the patient is known to have significant anemia or a prior lung resection.

Flow-Volume Loops

Interpreting the flow-volume loop involves looking at the pattern of the graph of airflow during inhalation and exhalation. The PFT machine will not provide an interpretation of the flow-volume loop so the physician or advance practice provider must do their own interpretation. There is a wealth of information in these graphs but too often, people ignore the flow-volume loop and go straight to the PFT numbers. This is a mistake because sometimes the only clue to a disease is found in the shape of the flow-volume loop. Also, the shape of the loop can be an indication that the patient gave poor effort during the test and the results may not be valid. The figure below shows the elements of a normal flow-volume loop with exhalation occurring during the top part of the loop and inhalation occurring during the bottom part. PEF is the peak expiratory flow. The FEF25% and FEF75% are the flow rates between the first 25% of the volume of exhaled air and the last 25% of the exhaled air. But what is important is the shape of the curve.

The shape of the normal loop should have an early expiratory peak with a gradual drop downward until the patient reaches the maximum amount of air that they can exhale (FVC). The inspiratory portion of the loop on the bottom should be more symmetric and look sort of like a half-circle. If the patient does not give a good effort, then the test is invalid and you should not believe the FVC or FEV1 numbers. In this situation, the shape of the loop will be very irregular as shown below:

Coughing during the test will also invalidate spirometry results and can be identified by a sudden drop in expiration causing a crevice or “double hump” to appear in the top portion of the loop:

There are two conditions that can result in flattening of the flow-volume loop. Vocal cord paralysis will cause flattening of the inspiratory limp but the expiratory limb will appear normal. Tracheostenosis will cause flattening of both the inspiratory and expiratory limbs of the flow-volume loop:

Patients with vocal cord dysfunction will clinically mimic asthma with dyspnea and wheezing. The flow-volume loop is often the first clue that a patient has vocal cord dysfunction. The expiratory limb of the flow-volume loop will appear normal but the inspiratory limb will be choppy and irregular. Vocal cord dysfunction can be confirmed by ordering a videolaryngostroboscopy study that will show that the vocal cords come together too much during inspiration, particular in the anterior portion of the vocal cords (anterior is the top portion of the photos below).

Putting it all together

If y0u have a full set of pulmonary function tests, these are the steps to interpreting the results that will be all you need to do in 99% of the PFTs you order:

  1. Is the spirometry test valid? Look at the shape of the flow-volume loop and also confirm that the patient’s demographics were correctly entered.
  2. Is the patient obstructed? Look to see if the FEV1/FVC ratio is low.
  3. If they are obstructed, how obstructed are they? This is determined by how low the FEV1 is below normal.
  4. If they are obstructed, is the obstruction reversible? This is determined by the amount of increase in the FEV1 and/or FVC after albuterol.
  5. Is the patient restricted? Restriction is present if the TLC is below the lower limit of normal.
  6. Is the diffusing capacity reduced? This is defined as a DLCO that is below the lower limit of normal.

Every type of lung disease will give a particular pattern of PFT results. The following table summarizes the most common lung conditions and their PFT patterns. The cells in the table that are shaded yellow are the key findings that point toward each of these 4 conditions:

When it comes to PFT interpretation, less is more. You really only need to know 5 numbers to interpret the overwhelming majority of PFTs. You can ignore the rest of the data and leave that for us pulmonologists who like to get way down in the weeds of the PFT report.

December 2, 2021

Categories
Medical Education

Lessons From The 2021 Residency Match

The annual residency match is an event like nothing else in the United States. Each year, 4th year medical students spend the fall and winter applying to and interviewing with residency programs. In February, they submit their ranked list of the programs that they would like to attend next year to the National Resident Matching Program. Simultaneously, all of the residency programs submit their ranked list of the medical students they would like to hire next year. The National Resident Matching Program then pairs the medical students with the residency programs using an algorithm that assigns the students to residency programs by matching the two rank lists. Although it sounds a bit impersonal, it actually is the fairest way to ensure that students get into the residency programs that they want while simultaneously ensuring that the residency programs get the students that they want.

The results of the match were released on Match Day, March 19th, and all across the country, 4th year medical students found out which hospital in which city they will be spending the next 3-5 years at starting in late June. If you drill into the Advance Data Table from this year’s match results, there are some interesting take-away points.

Some specialties are more competitive than others

There are 4 groups of students applying to residency: MD students, DO students, U.S. students attending foreign medical schools, and foreign students attending foreign medical schools. The most competitive specialties are those that fill most of their positions with U.S. medical graduates, and in particular, those graduating with MD degrees.

From this graph, it is apparent that surgical subspecialties are the most competitive residencies. Thoracic surgery, plastic surgery, otolaryngology, and neurosurgery all filled greater than 85% of their available positions with graduates from U.S. medical schools (MD). On the other hand, specialties that filled fewer than 50% of their positions with graduates from U.S. medical schools included radiation oncology, internal medicine, family medicine, and pathology.

The number of osteopathic graduates is growing

The number of applicants from U.S. allopathic (MD) medical schools has been rising slowly over the past 5 years. Combining the number of 4th year medical students applying for residency plus the number of applicants applying who previously graduated from allopathic medical schools, the total number has increased from 18,639 in 2017 to 21,538 in 2021, a 16% increase over 5 years. However, the number of applicants from U.S. osteopathic (DO) schools has increased from 3,590 to 7,710 over the same 5-year period, a 115% increase. Applicants from U.S. medical schools (MD) still have the best chance of getting into a residency with 92.8% of senior MD medical students matching. Seniors from osteopathic (DO) schools were a close second with 89.1% matching. U.S. citizens attending foreign medical schools fair less well with only 59.5% matching into a residency program. Foreign citizens attending foreign medical schools continued to be the least successful in getting a residency with only 54.8% matching. Over the past 5 years, despite the significant increase in numbers of senior students from osteopathic schools applying to residency, osteopathic students have been also been increasingly successful in obtaining residency with their match rate increasing from 85% in 2017 to 89.1% in 2021.

Competitive residencies require lots of ranks

In order to get into a residency program, a 4th year medical student must first apply to that program, then get accepted to interview at that program, then travel to the city where that residency is located to interview, then list that residency program on student’s rank list. In order to increase the chances of getting into a residency somewhere, you need to interview at and then rank several programs. In the past, that meant a lot of expensive travel across the country and a lot of time away from medical school to do those on-site interviews. This year, interviewing became a bit easier and less expensive since COVID-19 resulted in all interviews being done virtually, by video. Overall, the average senior student at an allopathic (MD) medical school ranked 9.4 residency programs. However, that number varied considerably. Not surprisingly, the average number of programs ranked per student correlated with how competitive the specialty is.Vascular surgery led with 20.5 programs ranked per applicant, followed by neurosurgery with 18.2, thoracic surgery with 18.1, and otolaryngology with 15.3. At the other end of the spectrum, students applying to pathology residencies ranked the fewest residency programs per student at 4.4, followed by family medicine at 4.9, and internal medicine at 5.7.

More students go into internal medicine

As in the past, the largest number of positions available is in internal medicine. Medical subspecialties such as cardiology, gastroenterology, pulmonary, and oncology first require an internal medicine residency so many of the students applying to internal medicine have long-term aspirations of subspecializing. Nonetheless, there are twice as many residency positions available for internal medicine (3,523) than are available for the next closest specialty, emergency medicine (1,765). Not included in these numbers are students seeking a preliminary or transitional year of internal medicine which is a pre-requisite before specialties such as neurology, dermatology, and ophthalmology. Of note, ophthalmology is unique in that the ophthalmology match occurs earlier in the year and does not participate in the regular residency match.

Your future doctor is less likely to be an MD

In the past, most U.S. physicians were graduates of U.S. allopathic medical schools and had an “M.D.” after their name. That is changing and with the current trends, this may be the last year that U.S. MD graduates comprise the majority of future physicians.

For the past 5 years, the number of available residency positions in the United States has been increasing. In 2017, there were 27,688 residency positions and this grew to 33,353 in 2021. Although the absolute numbers of applicants from each of the four types of students applying to residency has increased, the numbers of students from osteopathic schools, U.S. students attending foreign medical schools, and foreign students attending foreign medical schools has increased faster than the number of students from U.S. medical schools (MD). As a result, the percentage of students matching to residency from U.S. medical schools has fallen from 65.6% in 2017 to 50.7% in 2021. At this rate, the percentage will likely be < 50% next year. A total of 31% of students who matched this year trained at a foreign medical school, either as a U.S. citizen abroad or as a foreign citizen. That is up from 24% in 2017 and at this rate, in the near future, more U.S. physicians will have trained at a foreign medical school than at a U.S. medical school.

What happens to the students who don’t match?

Unmatched applicants included 1,431 U.S. medical school seniors, 866 U.S. medical school previous graduates, 774 osteopathic seniors, 339, osteopathic previous graduates, 2,143 U.S. citizens attending foreign medical schools, and 3,587 foreign citizens attending foreign medical schools. Combined, this is a total of 9,140 students who did not get into a residency. This is a mixed bag of students. Some will land a residency position in the “scramble” when unmatched students call program directors of residency programs that did not fill in hopes of getting a residency position after the match. Some will take a year or two off to get an MBA or other masters degree. Some will decide not to pursue medicine altogether and switch to another career. Some will take a year off to do research or work in another field and then try again next year.

Those unmatched students who apply to the match a second time face lower chances of obtaining a residency position. Of senior medical students applying to residency for the first time, 92.8% matched; however, of graduates of medical schools applying later, only 48.2% matched. The same trend exists for osteopathic students: 89.1% of senior students applying for the first time matched but only 44.3% of graduates applying later matched.

The results of the National Resident Matching Program tell us a lot about which specialties are hot and which specialties are not. But by looking more closely at the results, we can also forecast who our doctors are going to be in the future.

March 23, 2021

Categories
Medical Education

Making The Most Of Your Virtual Residency Interview

Fourth year medical students are facing challenges that no previous group of medical students have faced. The COVID-19 outbreak resulted in a loss of approximately 1/3 of their clinical rotation time during their third year of medical school as students were removed from our teaching hospitals in order to protect their own health. The re-direction from in-person to telemedicine outpatient visits was largely engineered to ensure continuity of patient care and physician income preservation – medical student education was left out of telemedicine. Students wanting to explore different hospitals or specialties not available at their own medical institution have seen clinical  “away rotations” eliminated due to travel restrictions. And now, the long-standing tradition of the residency interview has been radically changed with the replacement of on-site interviews with virtual interviews performed over the internet.

Residency Interviews are Expensive

In some ways, the virtual interview process brings benefits. Travel costs for medical students average $250 – $500 per interview and with students ranking an average of 12.5 residency programs in last year’s National Resident Matching Program, the typical medical student incurs about $5,000 in interview costs in order to apply to residency programs. There is a time cost as well, with one study finding that the average medical student spends 26 days traveling to interviews. Travel time and costs are the major factors that limit the number of programs a student can interview with.  The probability of matching to a residency program is dependent on both the number of programs a student ranks on their match list as well as the type of specialty that they have chosen. For example, 90% of U.S. medical students applying to pediatric residencies matched in their top 3 rank selections whereas 90% of internal medicine residency applicants  matched in their top 4 selections. Orthopedic surgery is considerably more competitive with 90% of applicants matching in their top 11 selections.

The Coalition for Physician Accountability has recommended that all residency programs commit to virtual residency interviews as opposed to in-person interviews for 2020. One implication of this is that medical students can interview at far more residency programs than ever before. There are no travel costs and a student can potentially interview with a residency program in California in the morning and a different program in New York in the afternoon. However, unlike medical students, residency programs are limited in the number of applicants that they can virtually interview since the faculty from those programs have only so many hours in the week that they can free-up from their regular duties to interview applicants.

One potential danger is that those applicants who appear the strongest on paper (based on grades and board examination scores) could take up most of the interview spots if they choose to interview at 30 or 40 programs. This could result in other applicants being closed out of interviews. As a result, many specialties are calling for a limit to the maximum number of residency programs that each medical student can interview with.

Preparation, Preparation, Preparation

In the past, when traveling to in-person interviews, students would use time in airports and hotel rooms doing background research on the hospital and city that they were heading to. This knowledge is the foundation for a successful interview. With virtual interviews, this down time evaporates so students need to find time in their regular lives to do that background investigation. Knowing about the physician faculty and the institutional areas of clinical expertise allows you to speak from a position of familiarity that in turn indicates your interest in that particular program.

Have a back-up plan in case your computer fails or in case of a technology failure at the institution you are interviewing with fails. That could be as simple as having a cell phone that could be used in a pinch. Also, be sure to log-on to the program 15 or 20 minutes before the time of your interview if possible – this will give you sufficient time to download an app or a software update needed for that particular interview. Make sure that your cell phone is turned to vibrate, your land line phone is off the hook, and your doorbell is turned off before you start your interview. Any programs or apps on your computer that can cause sound alerts should be closed.

Use the Right Equipment

If you are a medical student preparing for virtual residency interviews, you can only appear as good as your audiovisual equipment lets you appear. That means you will need to have a good camera and microphone. That 8-year old laptop that you got as a high school graduation present is not going to do the job. If you do not have a recent generation, high definition camera on your computer, then borrow or buy one. Since you are saving thousands of dollars in travel costs this year, it behooves you to spend a little money on a good webcam. In a previous post, I wrote about microphone selection for optimal audio presentations. To be sure that your camera and microphone are optimized, have a friend do a mock video interview with you with him or her using the equipment that you intend to use for the real interviews so that you can see what the interviewers are going to see. Make sure that you have plenty of bandwidth on your internet connection and since your interview may involve several different interviewers over several hours, be sure that your equipment is plugged in rather than running off of a battery.

Set the Stage to Your Advantage

In a virtual interview, it is not only how you look that is important, but also how your background surroundings look and sound. In a previous post, I wrote about how to improve your camera appearance for video conferencing and these points are equally applicable to the virtual interview. In particular, room lighting needs to be optimized. You should be in a quiet area, free noise created by cars driving on the street or created by your neighbor who practices his tuba in the apartment next to you. The stuff on the wall behind you will tell as much about you as the personal statement in your residency application so be sure that everything the interviewer sees in the camera field reflects the best in you. Be sure that you are in a location where you will not be interrupted – your child pounding on the door, your dog jumping in your lap, or your roommate walking around behind you in his underwear can derail your whole interview.

Dress for Success

It can be tempting to dress for your interview the same way that you normally dress in your apartment – casually. Instead, dress the same way you would if you are going to an in-person interview. If you are a guy, that means a tie and jacket. And don’t forget your pants – if you have to get up for any reason during the interview, you don’t want to be caught wearing your gym shorts. Make sure that the clothes that you wear contrast well with your background – wearing a white blouse in front of a white wall will cause you to fade away. Choose neutral colors – a medical student at the Ohio State University is better off not wearing a scarlet and gray necktie when doing a virtual interview at the University of Michigan.

Making a Good Impression on Camera

One of the criteria residency applicants are judged on during in-person interviews is eye contact. Poor eye contact can sink an applicant’s score on the residency program’s rank list. As humans, we rely on non-verbal communication with our eyes and facial expressions to augment our verbal communication. Video interviewing can disrupt this non-verbal communication. It can be tempting to look at the eyes of the person on the computer screen rather than the camera lens. The interviewers then perceive you as not making eye contact with them. Particularly when you are talking, look at the camera, instead of the computer screen. Shrink the video screen window and move it as close to your computer’s camera as you can. Head nods, smiles, and hand gestures can embellish your interview.

Practice for Success

2020 represents a paradigm shift in residency program interviews. The skills necessary for a successful in-person interview in the past will not always translate to a successful virtual interview this year. The disadvantage that this year’s senior medical students face is that no class of students has ever done this before so there is no precedent for today’s students to draw from. But students can also use this to their advantage. Those students who prepare can improve their interview performance and preparation means practice. Try out different video equipment and different locations. Do mock video interviews with other students and if possible, with faculty from your medical school to get feedback. Record mock interviews so you can see how you appear to the interviewer and then adjust your background, lighting, camera position, and clothes accordingly. This is an opportunity like no other before that allows students to leverage technology skills to set themselves apart from others in the residency selection process.

When it comes to 2020 residency program interviews, “…It’s showtime!”

August 15, 2020

Categories
Medical Education

Gender Bias In Lecture Acoustics

Last month, I attended the American College of Chest Physicians annual meeting. At one of the sessions, I realized I could hear the men talking but I had a hard time hearing the women despite the fact that they were all standing in front of the same lectern and all speaking in what seemed to be normal conversational speech. I realized that there can be implicit gender bias in lecture acoustics and that women need to be aware of some of these sources of acoustic bias in order to be effective speakers. There are several sources of acoustic gender bias. In this post, at the risk of being a male talking about female gender bias, I’ll explore several of these.

Gender differences in vocal frequency

Male and female voices occupy different sound frequencies. A typical male voice extends from 150 Hz to 6,000 Hz and a typical female voice extends from 350 to 8,000 Hz. However, in normal voiced speech, a male voice is 85 – 180 Hz and a female voice is 165 – 255 Hz. Certain vocal sounds occur at higher frequencies than others. For example, the sound of “J”, “M”, or “Z” occurs at a low frequency whereas the sound of “K”, “F”, or S” occurs at a much higher frequency.

Humans are wired to associate lower frequency voices with authority. In a study of male CEOs, the size of the company that a CEO ran correlated with the frequency of his voice – a lower voice pitch was associated with running a larger company and correlated with a higher salary. Interestingly, the average frequency of adult women’s voices has fallen by 23 Hz since 1960 which may reflect evolving societal differences in women in positions of authority. Because children have higher pitched voices than adults, a high-pitched voice can make a person sound young or inexperienced.

Many sound systems are adjusted to make the (often male) CEO sound great and this can put people with higher frequency voices at an inherent disadvantage unless there is someone tending the sound system who can make everyone sound just as great as the CEO.

We lose high frequency hearing with age

As we get older, our ability to hear high frequencies is diminished. Business owners use this to their advantage when they install a Mosquito alarm outside their buildings. This device emits an annoying 17,400 Hz noise that loitering teenagers can hear but older people are oblivious to. High frequency hearing loss begins at age 30 and increases with each decade of life.

As a result, many older people have a hard time hearing female voices with their higher frequency pitch. This is not an issue if you are lecturing to a group of college students. However, if you are lecturing to an older group of people or giving a presentation at a board meeting full of older board members, then a higher frequency voice is harder to hear. A woman often needs to speak slightly louder to be heard as well as her male colleague.

Equipment bias

There are two pieces of equipment that can affect how women’s voices project as opposed to men’s voices: the microphone and the equalizer. Each microphone will have a frequency rating that reflects how well it picks up different sound frequencies. A microphone that is better at picking up lower frequencies will tend to make a male voice sound louder and a female voice sound softer.

A second way that the microphone can cause discrimination by the “proximity effect”. This occurs because lower frequencies tend to be lost the further away a person is to the microphone. The average American man is 5 foot 9 inches tall where as the average American woman is 5 foot 4 inches tall, a difference of 5 inches. If a lectern microphone is set to position that microphone for the height of a man’s head, then a woman’s head is going to be 5 inches further away from that microphone with the effect of losing her lower frequency elements of speech. Therefore, simply by being closer to the microphone, you can augment the lower, or base frequencies in your voice. An easy way to demonstrate this is to use the “voice memo” app on your phone and record your voice saying the same thing with the phone 2 inches, 12 inches, and 24 inches away from your mouth. At 2 inches, your voice will have more base elements and will sound deeper and richer.

Microphones come in two general categories, directional and omnidirectional. A directional microphone picks up sounds from one specific direction and should be positioned so that it is pointed toward the source of that sound. An omnidirectional microphone picks up sounds from all directions from the microphone. The microphones on lecture room lecterns are usually directional so that the speaker’s voice is picked up but room noise is minimized. However, even with a directional microphone, as you increase the distance from the microphone, room noises will start to creep into the audio if the audio technician is attempting to maintain your voice at a constant volume. To ensure optimal acoustics, be sure that the directional microphone is pointed at your mouth.

 

Two other effects of the distance to the microphone is on reverberation and “popping noise”. Reverberation, or the echo of one’s voice in a room, becomes more evident when there are non-porous materials in the room (for example, concrete walls) and when one gets further from the microphone that they are speaking into. Those echos can make words harder to hear. If a person gets too close to a microphone, then the microphone can pick up puffs of air that can accompany sounds like the letters “p” or “b” and this can result in a distracting popping sound to one’s speech. Professional musicians overcome this by using a pop-filter composed of a piece of stocking-like material stretched and mounted as a screen between the microphone and the singer’s mouth. Pop-filters are impractical in a typical lecture room. The best distance is usually 6-12 inches between microphone and mouth; this distance is the best compromise between reducing popping sounds at the same time as reducing reverberation and room noise.

In order to account for different frequencies, equalizers are often used by sound engineers. An equalizer allows the engineer to preferentially amplify sounds in different frequency ranges and this can be used to “equalize” voices of different pitches, for example, men versus women. The bass and treble knobs on a radio are the most simple form of an equalizer. An equalizer in a lecture room can have between 5 and 31 sliders with each controlling a range of frequencies. Most lecture rooms don’t come with professional sound engineers, however, and so equalizers in a sound system may be set to a factory default frequency preference or the equalizer may be run by an audio-visual staff member with little idea of acoustic optimization. If you ever go to a small venue concert, the singer will almost always recognize the person running the sound system at the end of the show – how well that person manages the equalizer can make an enormous difference in how the singer sounds. The person running the lecture room sound system is just as important to the effectiveness of the lecturer.

Room bias

The acoustic response of a room if affected by many variables but one of the more important is the degree of absorption of different frequencies. Porous materials in a room, for example, carpet or fabric, can reduce reverberation and echos but will also absorb high frequency sounds. Thus, a person with a high frequency voice may not seem to be as loud as a person with a lower frequency voice. The more porous materials are in a room, the more a woman’s voice can be lost.

The individual’s “voice brand”

There are 5 main features of a person’s individual voice brand: intensity, inflection, rate, frequency, and quality. Adopting different elements of each of these features can significantly impact the effect a voice can have on a listener.

Intensity is the loudness of a voice in decibels. Too soft of a voice can come across as meek and timid but too loud of a voice can come across as if you are shouting or angry.

Inflection is the intonation of voice or the degree to which the pitch varies. An excessively monotone voice has little variation in the frequency of the words spoken and can come across as uninteresting. An excessively up-and-down voice with constant swings in the frequency of words can come across as unintelligent.

Rate is the speed of one’s speech. Too slow comes across as condescending but too fast comes across as being rushed. Varying the rate of speech can be an effective way of emphasizing certain points. A good rate range is 162-175 words per minute.

Frequency is the pitch of the voice, usually measured in hertz (Hz). Too high of a frequency can make one sound young or less intelligent, as discussed above. Too low of a frequency can be authoritative but can also come across as aggressive.

Quality are those characteristics of a voice that can create an “interesting voice”. Two voice qualities to avoid in public speaking are the “glottal fry” and “up-talking”. Glottal fry is when a person takes their voice down to an unnaturally low pitch during part of a phrase resulting in a creaky or graveling timber. A study of voice perception found that people over age 40 believe that speakers using vocal fry sound like they lack authority. Up-taking, or high rising terminal, is when a person increases the frequency of their voice at the end of a sentence. This results in a tone that sounds like a question and can make the speaker come across as unsure of themself or uncomfortable.

So what can women do?

To create an equal acoustic playing field, there are some things that you cannot control. For example, you cannot control the shape of the room, the extent of porous room materials, or the frequency rating of the microphone. However, there are some things that you can control and you can use these to your advantage.

The first thing one can do is to speak louder. As men and women speak in a loud (but not shouting) voice, the differences between the acoustic perception of different frequencies of sound become less apparent. So, if a woman speaks slightly louder than normal, she can eliminate the auditory perception gap that exists between male speech and female speech, particularly in the lower vocal frequencies. This becomes more necessary when a woman is speaking to an audience of mostly older persons.

A second strategy involves speaking with the person running the sound equipment for the lecture room (when such a person exists!). Many times, they will have set the equalizer to a default setting or they will have optimized it for whoever the first speaker is. If that first speaker is a man with a low pitched voice, then the woman who is the second speaker will often be acoustically disadvantaged. Asking the sound technician to be sure to adjust the equalizer when you are giving your presentation will remind that technician that you are aware of the importance of what they do and ensure that he or she optimizes the settings for the unique frequencies of your voice.

A third strategy is to adjust the microphone height. In order to retain the authoritative lower frequency vocal intonations, one has to maintain proximity to the microphone. Sometimes this may mean adjusting the height of a lectern (if it is adjustable) and sometimes this means bending a flexible goose-neck microphone down to an appropriate height. Stand close to the microphone with a goal of your mouth being 6-12 inches away. Be sure that the microphone is pointing directly at your mouth. Lavalier microphones are a great choice because they stay pointed directly at the mouth and they stay a fixed 8 inches from the mouth.

A fourth strategy is to adjust your voice brand. Most of us do not really know how we sound to others. Recording a practice session of your presentation and then listening  to it can help you identify features such as glottal fry and up-talking that may not have much impact on younger audiences but can make you seem less authoritative to older audiences. Ensure that your rate is 162-175 words per minute and that your intonation is neither too monotone nor too up-and-down.

To be successful, it is important to not only be qualified but to also sound qualified.

November 12, 2019

Categories
Medical Economics Medical Education

The Total Cost To Train A Physician

It costs more than $1.1 million to train a doctor in the United States. The societal investment in creating physicians is enormous and has widespread implications for American health care in everything from acceptance of international medical graduates to the future use of non-physician health care providers.

Breaking down the costs

Depending on the specialty, tt takes 11 to 15 years to train a physician when you count college, medical school, residency, and fellowship. At each of these steps there are direct costs and indirect costs. Some of these costs are paid by the physician in training and some of these costs are paid for by society in general (usually through state or federal taxes). Here is a breakdown of the direct and indirect costs at each step along the way:

Undergraduate education. Colleges essentially have 3 sources of income: tuition, endowment, and government funds. For this reason, the total cost to educate an undergraduate is considerably more than what the student actually pays in tuition. It becomes complicated because most colleges not only have to finance the education of students but also have to finance the research activities that professors must perform in order to keep their jobs. Thus, it is hard to separate the costs of education from the costs of research. Public colleges receive state government funds to subsidize their education and research activities and this results in lower tuition for in-state residents than for out-of-state residents. The out-of-state tuition and fees best reflects the cost to teach an undergraduate without the state governmental subsidy. Private colleges and universities generally do not receive state governmental subsidies and have considerably higher tuition costs. For the purpose of this analysis, I used the current cost of attendance for out-of-state freshman at the Ohio State University that includes tuition, fees, books, room, board, and miscellaneous expenses if living on-campus which is $49,556. For four years of college, this would be a total cost of $198,224.

Medical school. Colleges of medicine have the same 3 sources of income as undergraduate colleges so for this analysis, I used the current cost of attendance for an out-of-state medical student at the Ohio State University College of Medicine. Once again, this estimate is for tuition and fees as well as estimated living expenses. Unlike undergraduate college, the cost of medical school varies considerably for each of the four years of training: year one = $80,019, year two = $76,026, year three = $114,442, and year four = $114,542. Totaling all four years, the cost to go to medical school is $385,029.

Residency. There are both direct and indirect costs of resident education. The direct costs are the resident’s salary and benefits. At the Ohio State University Medical Center, these costs are $51,510 for a first year resident (intern) and increases each year so that a fourth year resident cost is $56,636. However, the direct costs are only the tip of the iceberg when it comes to the total cost to train a resident. There is the cost of everything from hospital call rooms, to residency program administrator salaries, to part of the salaries of chairmen and faculty to cover otherwise non-compensated teaching time. Most of these indirect costs are ultimately paid from federal tax dollars- either by Medicare payments to teaching hospitals for graduate medical education or by the higher Medicare payments for clinical services that teaching hospitals get paid (as opposed to non-teaching hospitals). In 2014, the Alliance for Academic Internal Medicine estimated that the total direct and indirect costs to train a resident is $183,416 per year. For the 3 years of residency it takes to become a general internist, pediatrician, family physician, or hospitalist, the cost is $550,248. It takes longer to train other specialists, for example, an obstetrician is 4 years ($733,664), a gastroenterologist is 6 years ($1,100,496), and an interventional cardiologist is 7 years ($1,283,912).

Total costs. Adding all of these together, the total costs to train physicians is astounding. This demonstrates that society has an enormous investment in each physician in the United States.

  • $1,133,501 – general internist, family physician, pediatrician
  • $1,316,917 – obstetrician, psychiatrist
  • $1,500,333 – general surgeon, endocrinologist
  • $1,683,749 – gastroenterologist, pulmonary/critical care, general cardiologist
  • $1,867,165 – interventional cardiologist, neurosurgeon

Implications for U.S. healthcare

International medical graduates. One of the best ways to reduce the cost of training doctors is to get someone else to pay for it. If you can get another country to cover the costs of college and medical school, then the cost to American society drops. Therefore, the U.S. cost to train a family physician who is an international medical graduate is $583,253 less than a family physician who is a U.S. medical graduate. In other words, the cost to American society of an international medical graduate is about half that of a U.S. medical graduate.

Non-physician providers. Nurse practitioners and physician assistants are far less expensive to train than physicians. The typical NP or PA training consists of 4 years of undergraduate training plus 2 years of NP/PA training. The costs to become an NP or PA is approximately $84,598 after college (tuition and living expenses) and the total cost including college is $282,822. In other words, the cost to train a family practice NP/PA is only one-fourth of the cost of training a family practice physician. Given that NPs and PAs increasingly have a similar scope of practice as physicians, from a societal standpoint, it will be a lot less expensive to train an NP or PA than it is to train a physician to do the same job. The implication is that NPs and PAs will replace many physician jobs in the future.

Repairing broken physicians. In a meeting I was recently attending, a question was asked whether we have different standards for terminating physicians with behavioral problems or substance abuse than we do for terminating other health care workers for the same problems. The reality is that I think we probably do and part of this is because of the enormous societal investment in those physicians. To create an analogy, if you have a broken handle on a screw driver that cost $2, you buy a new screw driver and don’t pay the cost of repairing it. On the other hand, if you have a broken handle on an airplane that costs $1.2 million, you repair the handle rather than throwing out the entire plane. If society invests $1.2 million to create a physician who then develops alcoholism, one can make the argument that hospitals have a societal obligation to first attempt to cure the physician and return him or her to practice when/if safe to do so rather than permanently end that physician’s career. Like it or not, hospitals will often put broken physicians on leave and attempt to rehabilitate them for infractions that would result in an unskilled employee being terminated – it is not necessarily fair but it is an economic reality. On the other hand, if an airplane has a critical mechanical flaw that puts it in continuous danger of crashing, you decommission that airplane – physicians with critical flaws should similarly be decommissioned.

Discussions about the cost of training physicians usually center around the cost to the individual physician and often stop at the average debt of a graduating medical student. But beyond medical student debt, there is a much larger cost that is not paid directly by the doctor but is paid more broadly by the institutions that provide scholarships, by the citizens who pay state and federal taxes, by direct salary costs of residents who cannot bill for their services, and by the indirect costs to hospitals to train residents.

July 11, 2019

Categories
Medical Economics Medical Education

Predicting The Future Of Medicine In 2035

I was asked to give a talk to the new internal medicine interns this week and it gave me a chance to think about what it is that we are training them for. Wayne Gretzky famously said “I skate to where the puck is going to be, not where it has been.” If we are going to be effective teachers of medicine, we need to train our interns and residents for the way medicine will be, not how it was in the past or even how it is now. So, what will medicine look like 16 years from now in 2035? The Accreditation Council for Graduate Medical Education (ACGME) has created a vision for medicine in 2035 to help residency programs prepare tomorrow’s practicing physicians. I agree with a lot of what the document concludes and I’ve added some of my own projections about what medicine will be like in 2035:

It is going to be more complex. As we learn more about the causes of disease and as we develop more specifically targeted treatments for disease, the complexity of medicine will increase exponentially. Take the example of oncology: 20 years ago, a physician would specialize in hematology & oncology and that was pretty much the end of the story. As knowledge and treatments increased, the discipline split so that physicians either became a hematologist or an oncologist. Now, oncology has split further so that a physician becomes a breast cancer oncologist, or a lung cancer oncologist, or a gastrointestinal cancer oncologist. In the past, lung cancer was either small cell or non-small cell lung cancer; now non-small cell lung cancer is subdivided into many different varieties based on specific driver mutations and each of these varieties are treated differently. As we further subdivide diseases into different groups based on biochemical or genetic differences, we get newer and more complicated drugs to treat them with. Last year, the FDA approved 59 new drugs; at that pace, there will be nearly 1,000 new drugs on the market in 2035 that do not exist today.

Medical information will become more transparent. In the past, medical information was locked away in a paper chart stored on a shelf in a hospital medical records department storeroom. Now, the finest details of patients’ medical history, lab test results, and x-rays are available to just about any physician in the country who is involved in the care of that patient. In minutes, I can have radiographic images appear on my computer screen from a chest CT scan a patient had in California earlier that morning. Patients can view all of their test results and even their doctor’s progress notes real-time. Information transparency shows no sign of letting up and more people will be able to access more health information than ever before. Not only will patient medical information become more transparent, but the way we take care of patients will become more transparent. Already, you can see what any given hospital’s readmission rate, emergency department waiting time in minutes, and surgical complication rate is with a quick trip the the Medicare website.

Commoditization of medicine will increase. Health care in the United States is a business. Already, hospitals are buying and selling physician practices, healthcare systems are acquiring hospitals, and health insurance companies are merging with drug store chains. Hospitals are now federally mandated to publicly post the prices for all of their services. There is pressure to reduce costs by using the least expensive employees to provide care. Non-traditional healthcare locations are being used where profit can be made. You don’t need to look any further than your local pharmacy where medications are dispensed based on a patient’s insurance formulary, the pharmacists will administer vaccinations directly to patients, and a nurse practitioner will manage common acute illnesses in a “minute clinic” – all of which were decisions previously made by and services previously provided by physicians. Americans are entrepreneurial to the core and the business of medicine will increasingly mimic the business of other commodities.

Advanced practice providers will increase. 2013 was the last year that there were more MD degrees awarded in the United States than CNP degrees. The certified nurse practitioner workforce is increasing exponentially. 20 years ago, nurse practitioners worked for physicians as so-called “physician extenders” and did not prescribe medications. Now, NPs work independently and have prescriptive authority. It makes sense – it takes 2 years of education after a bachelor’s degree to become an NP but it takes 7 years of education after a bachelor’s degree to become a family physician. In addition, the typical NP salary is less than half that of a family physician. So, if an NP can do the same thing as a primary care physician at half the cost and with 28% of the training, the commoditization of medicine will encourage hospitals and clinics to hire NPs into roles that they would previously have hired physicians. In the U.S. graduation class of 2017, there were 26,000 NP graduates, 19,259 MD graduates, and 8,336 PA graduates. In the near future, it is likely that the annual number of physician assistant graduates will also exceed the number of physician graduates, just like nurse practitioners already do. Medicine will increasingly be a team sport with physician playing a more smaller role in the team than in the past

Artificial intelligence will proliferate. IBM’s Watson is just the first, rudimentary foray into the use of computers in disease diagnosis and management. Already, I have patients who type 4 or 5 of their symptoms into Google and come to the office asking if they could have whatever disease appears on their Google search. And why shouldn’t it be this way? Physicians are forever missing diagnoses, overlooking test results, and choosing the wrong drug. For years, the mantra of hospital quality departments has been to standardize care and no one can standardize better than a computer.

The patients will be older. The U.S. demographic is changing and in 2035, the number of older Americans will exceed the number of young Americans. This will increase the demand for physicians who provide care to the elderly, such as geriatricians and orthopedic surgeons. As the percentage of Americans over age 65 increases, so will the influence of Medicare on American healthcare as Medicare assumes a more dominant role in U.S. health insurance.

Many of today’s skills will become obsolete. As an intern in 1984, I was required to offer to do a rigid sigmoidoscopy to every patient over age 60 who was admitted to the hospital; I did a lot of rigid sigmoidoscopes that year. Bronchoscopy was not readily available so we would do transtracheal aspirates using an angiocath and a syringe if we needed a sputum sample in a patient who couldn’t cough it up. If I did a lumbar puncture in the middle of the night, I was expected to do a diff quick stain, a gram stain, an India ink prep, and an acid fast stain of the spinal fluid in the residents’ lab down the hall from the ICU.  And if a patient had unexplained thrombocytopenia, it was the intern’s job to get a bone marrow biopsy tray, do a bone marrow aspirate, and then stain that aspirate before rounding with the attending physician. As interns, we did all of the blood cultures and the EKGs. Today, no intern or resident is required to do any of these things; in fact, we don’t even let our residents do their own specimen stains due to CLIA restrictions. In 2035, new interns will chuckle when they hear about the “bad old days” in 2019 when doctors did all sorts of procedures that were replaced by better ways of doing things.

A lot of today’s knowledge will turn out to be wrong. Perhaps the most visible manifestation of this is in advanced cardiac life support (ACLS). As a critical care physician, I’m required to re-certify in ACLS every 2 years and since I first took it in medical school, I’ve taken the ACLS course 18 times. Each time, the guidelines are a little different and the correct answers to the questions on the test you have to take are different. It turns out that many of the drugs we used didn’t actually work and the best way to “run a code” turns out to be completely different than what we thought it was. In my first year of medical school, one of the professors told us that 50% of everything we were about to learn will turn out to be wrong… and he was right. The only unchangeable thing about medicine is change itself.

Doctors will be paid differently. In 1965, Medicare was invented and this led to standardization of physician fees… doctors thought it was the end of the world. In the 1970’s DRGs (diagnostic related groups) were rolled out to standardize the way that hospitals got paid for a particular diagnosis or surgical procedure… doctors thought it was the end of the world. In the 1990’s RVUs (relative value units) were created to standardize the way doctors got paid for specific services or procedures… doctors thought it was the end of the world. Now, we are basing physician compensation on value metrics… doctors again think it is the end of the world. Our problem is that healthcare is so expensive. In 2017, the healthcare costs for the average American was $10,224, nearly double the cost per person in economically similar countries. As a percent of GDP, we pay more than any other country for healthcare and that gap is increasing every year. Although we can’t predict what physician compensation model will be in place in 2035, it is clear that our past models of healthcare financing are unsustainable.

The solo practitioner will become extinct. Physician employment models have changed unfathomably fast in the past decade. In just 6 years, the percentage of physicians who are hospital-employed increased from 26% to 44% nationwide. However, there are substantial regional differences such that in the Midwestern United States, 55% of physicians are now employed by a hospital. The solo practitioner or even the small physician group cannot negotiate for favorable payment rates from health insurance companies – only very large groups and larger health systems have the clout to negotiate high payments for physician services from insurance companies. Furthermore, as medicine has become more regulated, it it harder and harder to be sure that you are practicing according to the rules: physicians have to have sufficient support staff to be sure that billing is compliant, HIPAA laws are not violated, and the electronic medical record network is regularly updated – it takes a lot more staff than a solo practitioner can afford to hire. The solo practitioner is not a viable business model for the future.

Results of the 2019 fellowship match

There will be more international medical graduates. American doctors make more money than doctors in any other country. So, naturally, doctors in other countries like to come to America because they can make a better living. It works out well for the U.S. healthcare system as well – medical school in other countries is generally either heavily subsidized or completely paid for by the governments of those countries so in the end, some other country is paying to train doctors who end up practicing in the U.S. Currently, 24.3% of physicians in the U.S. are international medical graduates but there are significant differences by specialty. For example, 38.6% of internists are international medical graduates as are 50.7% of geriatricians. As I pointed out in a previous post, more nephrology fellowship positions were filled by international medical graduates than U.S. medical graduates this year.

Is there anything that won’t change? The good news is, yes, and no one said it better than Francis Peabody who wrote in his 1927 article in the Journal of the American Medical Association: “... the secret of the care of the patient is caring for the patient.” That tenet held true in 1927, still holds true today, and will hold equally true in 2035. No matter how much we come to depend on artificial intelligence to help us diagnose and manage disease, no matter how many more NPs and PAs are trained, and no matter how commoditized medicine becomes, one quality of being a physician that won’t change is in caring for the patient. Humanism is that one unchangeable thing.

July 4, 2019