Emergency endotracheal intubation is commonly performed in patients with cardiac arrest, loss of consciousness, or severe respiratory failure. A study published this month in the New England Journal of Medicine found that emergency intubation using video laryngoscopes is more successful than intubation using direct laryngoscopes. In the hospital, emergency intubations typically occur in the emergency department, intensive care unit, or in a regular hospital bed and these patients are by definition physiologically unstable. In contrast, elective intubations are performed in the operating room under controlled conditions in surgical patients who are usually physiologically stable. Over the decades, I have performed or supervised hundreds of emergency intubations and there are always two goals: (1) do it fast and (2) do it right the first time. During the emergency intubation procedure, the patient is unable to breath effectively and if too much time is taken or too many attempts are required, the patient can become dangerously hypoxemic.
For years, the only way to intubate a patient was by using a direct laryngoscope. There are two main types, the Macintosh laryngoscope and the Miller laryngoscope. Both have a handle that contains batteries and a blade that is inserted into the mouth to pull the tongue out of the way in order to get a view of the vocal cords. In the blade of the direct laryngoscope, there is a small light bulb to help improve the ability to see the vocal cords. Once the laryngoscope is inserted into the mouth, a plastic endotracheal tube is guided through the vocal cords and into the trachea.
The Macintosh laryngoscope has a curved blade and comes in a variety of sizes. My go-to laryngoscope blade for most of my career was a #3 Macintosh. For large patients, I would sometimes use a #4 Macintosh. The Miller blade is straight. I personally found it harder to use for most patients but it was sometimes helpful for obese patients and in situations when I just could not get a good view of the vocal cords with a Macintosh blade. The Miller blade also comes in a variety of sizes. In the past, direct laryngoscopes were reusable after sterilization but most hospitals now use disposable, non-reusable laryngoscopes.
Intubation using a direct laryngoscope requires the operator to be directly behind and above the patient’s face, within a few inches of the mouth. You have to wear a face mask and plastic face shield – it is pretty common to get spattered with sputum, blood, saliva, or vomit. Because you are so close to the patient’s airway, there is also a risk of becoming infected with a contagious microorganism. This was a big danger during the COVID pandemic and we largely abandoned direct laryngoscopy when intubating COVID patients because of this risk.
About 15 years ago, a new type of laryngoscope emerged on the market that uses a tiny camera at the end of the laryngoscope blade, adjacent to the light bulb. The view from the end of the blade can then be displayed on either a small video monitor attached to the laryngoscope handle or a larger video monitor connected to the laryngoscope by wires. The downside of video laryngoscopes is that they are far more expensive to purchase and maintain than direct laryngoscopes.
The video laryngoscope blades are all curved and have a greater degree of curve than the Macintosh blade. Because of this, they require a special curved rigid metal stylet to be inserted into the endotracheal tube. Once the tip of the endotracheal tube is positioned just above the vocal cords, the endotracheal tube is advanced while simultaneously pulling back on the stylet so that the endotracheal tube can assume a straight path in the trachea, below the vocal cords. This usually requires an assistant to control the stylet or an extremely dexterous operator who can control both the stylet and the endotracheal tube with one hand.
There are three main advantages to the video laryngoscope. First, you can get a better view of the vocal cords than with the direct laryngoscope. This is especially true in patients with “anterior” larynxes that are hard to see with direct visualization through the mouth and in patients with large tongues that obstruct direct visualization. The Mallampati score is often used to classify the airways – those with Mallampati class III or IV airways are better seen with the video laryngoscope. Second, the video laryngoscopes allow the operator’s face to be a couple of feet away from the patient’s nose and mouth, rather than a few inches as with direct laryngoscopes. This can reduce the chances of acquiring a communicable disease. For this reason, video laryngoscopy became our preferred approach to intubating patients with COVID infections. Third, it is easier to teach trainees how to perform endotracheal intubation since the attending physician can point out the anatomy and see if the trainee is inserting the endotracheal tube correctly. In contrast, during direct laryngoscopy, only the person actually performing the intubation can see the vocal cords and watch the tube insertion so it is not possible for the attending physician to know if the trainee is performing the intubation correctly.
Which method of laryngoscopy is better?
Anecdotally, our pulmonary/critical care fellows tell me that they get proficient with endotracheal intubation faster using video laryngoscopy than using direct laryngoscopy. They cite the better view of the vocal cords plus the improved feedback from the supervising attending physician. From my own personal experience, I found that video laryngoscopy was particularly useful in those patients who I could not get a good view of the vocal cords during an initial intubation attempt with a direct laryngoscope. But anecdotes are not as persuasive as randomized, controlled, multi-center trials. So, what does the medical literature show?
A 2021 study in JAMA found that worldwide, 81% of emergency intubations are performed using direct laryngoscopy. There have been a number of studies comparing direct and video laryngoscopy for endotracheal intubation. Some have shown that both techniques are equally successful, others have shown that video laryngoscopy is superior, and others have shown that direct laryngoscopy is superior. But until recently, there have been no large, randomized, multi-center trials comparing the two techniques for emergency intubation. In a 2020 review of tracheal intubation in critically ill patients published in the American Review of Respiratory and Critical Care Medicine, the recommendations stated that video laryngoscopy should be available in every ICU and ER and that the first attempt at emergency intubation should be made using video laryngoscopy. The recent study in the New England Journal of Medicine now provides the most convincing evidence to date that video laryngoscopy is superior to direct laryngoscopy during emergency endotracheal intubations.
What the study found. In this study, 1,417 patients undergoing emergency endotracheal intubation at 11 U.S. hospitals in 2022 were randomized to the use of video laryngoscopy or direct laryngoscopy for the first attempt at intubation. 70% of patients were in emergency departments and 30% were in ICUs. Because all of the hospitals were teaching hospitals, the vast majority of intubations were performed by trainees: 72% were by residents and 24% were by fellows. Notably, these are less experienced physicians who have performed fewer intubations than more senior attending physicians. The findings were statistically significant: 85% of patients were successfully intubated on the first attempt using video laryngoscopy but only 71% of patients were successfully intubated on the first attempt using direct laryngoscopy. It also took the operators less time to perform intubation using video laryngoscopy (38 seconds) than using direct laryngoscopy (46 seconds).
What the study did not find. Because the overwhelming majority of intubations (96%) were performed by trainees, it is uncertain whether video laryngoscopy is also superior to direct laryngoscopy when experienced attending physicians are performing emergency intubation. Anecdotally, I believe that video laryngoscopy is superior, at least from my own personal experience using both types of laryngoscopes. The study only examined emergency intubations and not elective intubations (such as occur regularly in the operating room). Therefore, the results do not necessarily mean that we should abandon direct laryngoscopy for elective surgeries. Finally, there were no differences in procedural complications using the two types of laryngoscopes.
So, what should hospitals do?
For the hospital medical director or the medical director of an emergency department or intensive care unit, there are several practical implications from the most recent study:
- Training programs should incorporate video laryngoscopy. All health care providers who perform emergency endotracheal intubation should be taught to use video laryngoscopy during their formal training programs. In the United States, emergency intubations can be performed by a variety of providers including residents, fellows, attending physicians, respiratory therapists, EMTs, CRNAs, nurse practitioners, and physician assistants. Each hospital is different, depending on the staff availability, state laws, and hospital regulations. Moreover, emergency intubations in the ICU and during cardiopulmonary arrests often occur at night or weekends when experienced attending intensivists and anesthesiologists are not immediately available.
- Make training available to existing staff. Newly trained ER residents and critical care fellows will already be experienced using video laryngoscopy devices and should not be required to undergo additional training as attending physicians. However, it is necessary to have a process in place to train more senior physicians and other health care providers in the use of the equipment. Because internal medicine residents are no longer required to be trained in intubation, at our hospital, we developed a “Difficult Airway Course” for our hospitalists who covered the ICU at night and who responded to cardiopulmonary arrests in the hospital. This included demonstration of the video laryngoscope equipment and opportunity to use the video laryngoscope to intubate manikins. It took less than an hour and was included as part of orientation for new hospitalists. To make training even more palatable, offer CME credit.
- Video laryngoscopes should be available wherever emergency intubations are performed. At a minimum, this should include emergency departments and intensive care units. However, cardiopulmonary arrests can occur anywhere in the hospital so there should be protocols in place in order to deploy video laryngoscopes rapidly to any location in the hospital.
- Choose a brand (and stick with it). To date, there are no studies comparing one type or brand of video laryngoscopes to another. The decision about which video laryngoscopes the hospital should purchase should be made based on preference consensus of physicians who perform emergency intubation and on cost. In my own experience using multiple types of video laryngoscopes, I recommend choosing one type and then using that one type throughout the hospital, rather than having different types or brands in different hospital locations. Although they are all relatively similar, even a few extra seconds required to figure out how to use an unfamiliar brand of a video laryngoscope during cardiopulmonary resuscitation can result in patient harm.
- Buy enough devices. Medical equipment periodically breaks and has to be sent out for repair or replaced. It is important to always have back-ups in event of breakage. In addition, patients do not schedule their need for emergency intubation and there can be several emergency intubations during any given ER or ICU shift. Have enough video laryngoscopes to accommodate multiple intubations occurring simultaneously and if your video laryngoscope requires cleaning and sterilization, be sure you have enough video laryngoscopes on hand to last until equipment can be cleaned.
- Don’t completely abandon direct laryngoscopy. Because direct laryngoscopes are inexpensive and small, hospitals can afford to keep them in every crash cart and airway kit. It is prudent to always have a direct laryngoscope on hand in case the video laryngoscope quits working in the middle of an intubation. Furthermore, the availability of multiple sizes and shapes of the direct laryngoscope blades allows a more tailored selection of equipment for patients with larger or more unusually shaped mouths. When it comes to emergency airway management, it is always important to have a back-up plan and direct laryngoscopy is the key component of the back-up plan for video laryngoscopy. The implication is that we must therefore continue to teach our trainees how to use direct laryngoscopes and not completely abandon them from ER residencies and critical care fellowships.
- Recommend but do not require the use of video laryngoscopy. When ultrasound to guide central venous catheter placement first came out in the late 1990’s, many of us thought that ultrasound would soon come to used for all central line procedures. Indeed, almost all residents and fellows adopted ultrasound. But many attending physicians who were very experienced and adept at performing central lines found ultrasound slowed them down and did not improve their already very high success rates. A physician who is highly skilled using direct laryngoscopy may have better outcomes continuing to use the equipment he/she is comfortable and experienced with, rather than being forced to change to new equipment. Many physicians are resistant to change but most physicians find that once they actually use video laryngoscopy, they do not want to go back to direct laryngoscopy.
- Avoid special credentialing. Another lesson from vascular ultrasound for central line placement was credentialing. When hospitals first acquired these ultrasound devices, there was concern that the operation of the ultrasound equipment and the interpretation of the ultrasound images required specialized skills. Consequently, hospitals required physicians to have special credentials in order to use ultrasound to facilitate central venous catheter placement. Credentialing required several hours of training and required proctored performance of several ultrasound procedures before the physician was permitted to use vascular ultrasound. This posed a barrier to its implementation because many attending physicians found it easier to continue to do non-ultrasound guided procedures rather than take the time and effort to get credentialed for the use of ultrasound. In hindsight, this was a mistake and should be avoided with video laryngoscopy.
The two goals of emergency endotracheal intubation are to: (1) get it done fast and (2) get it done right the first time. Video laryngoscopy offers an improvement in both of these goals compared to direct laryngoscopy. It is time to equip our emergency departments, intensive care units, and crash carts with these devices. And it is time to encourage our health care providers to adopt their use.
June 21, 2023