Airway management in 2020: Different and scarier

It’s early May in Los Angeles, and dystopian reality is here – storefronts boarded up; people (if they’re out at all) wearing sinister-looking black facemasks. Inside the hospital, everyone wears a mask all the time, no one gathers in clusters to chat, and even the tail-wagging therapy dogs must be sheltering at home because they’re nowhere to be seen.

One change I didn’t see coming was a metamorphosis in airway management.

Guidelines developed for the intubation of COVID-19 patients are evolving into the new normal whether a patient is infected or not. This is even more remarkable since anesthesiologists consider ourselves experts in airway management, and many of us (how can I put this kindly?) hold firmly to our opinions. Who would have thought old habits could change? But airway management this year is different and scarier. Remember when we didn’t think of it as hazardous duty?

Who still “tests” the airway?

Consider the question of whether to “test the airway” before giving any neuromuscular blocker (NMB) during a routine anesthesia induction. Some of us believe that it offers a measure of safety, because you can back out and wake the patient up if you can’t ventilate. Those (like me) who don’t do it quote studies that demonstrate more effective mask ventilation with larger tidal volumes after NMB, and point out that if you can’t ventilate, most people will give NMB anyway.

That controversy seems to have gone into hiding. Today, the guidelines for intubating a patient with proven or suspected COVID-19 recommend rapid-sequence induction (RSI) to reduce the risk of the patient coughing and spraying the area with aerosolized coronavirus. No one in that situation seems worried about testing the airway.

What about the patient who is asymptomatic, and has a recent negative COVID-19 test result? There is legitimate concern that the patient could still be in the early, asymptomatic stage of infection, and the incidence of false negative results from COVID-19 testing could be as high as 30%. By that logic, we should treat every patient as a PUI, and perform RSI on all comers. It would be interesting to survey anesthesia professionals and see how many now perform RSI as their default approach. Certainly, residents now ask me on nearly every case if the plan is RSI, and I hear from colleagues at other institutions that my experience isn’t unique.

What about extubation?

If we don’t want coughing on intubation in the era of COVID-19, logically we wouldn’t want it on extubation either. Awake extubation, especially in the hands of novices, can include an alarming display of coughing and struggling by the patient, accompanied by cries of “Open your eyes! Take a deep breath!” by the person at the head of the table. More coughing follows as the tube comes out. In contrast, a recent review article on the care of COVID-19 patients advises removing the endotracheal tube “as smoothly as is feasible”. For our colleagues in the United Kingdom who are accustomed to deep extubation, this is routine. In America, it isn’t.

Anecdotally, there is new interest stateside in the art of deep extubation. If you’re experienced with it, there couldn’t be a better indication for deep extubation than the COVID-19 pandemic, and you’ll probably hear less backtalk from those who still think it’s dangerous. However, anyone who hasn’t been well trained in deep extubation, or who hasn’t practiced it in quite some time, has no business trying it in a high-stress situation. There are other ways – dexmedetomidine, lidocaine, ketamine, opioids – to achieve a tranquil, cough-free emergence.

How will medical students and residents learn?

As the universities evacuated this spring, the medical students disappeared along with the undergraduates. It’s unclear when they’ll be back or how they’ll make up the lost time. The anesthesiology residents are here, but at many programs they’ve been kept away from the intubations in the emergency department (ED) and the COVID-19 wards.

In the operating room, it would be interesting to know how many anesthesiologists find that they’re less willing now to let a resident struggle with mask ventilation, if they allow it at all. Certainly, it’s not easy to teach mask ventilation today with so many obese patients. Residents with smaller hands have difficulty reaching the mandible even on normal-size adults, and need to learn alternate methods such as the modified chin-lift. If they have fewer opportunities to ventilate by mask, it will be tough to learn to do it well.

Will COVID-19 succeed in making the video laryngoscope (no matter what brand you choose) the default standard of care? Will residents ever learn fiberoptic intubation? The same guidelines that encourage RSI also recommend video laryngoscopy and avoiding fiberoptic intubation for any patient suspected of COVID-19. Cost may be the only reason keeping many departments from adopting video laryngoscope use today for every case. Why drive without headlights when headlights can be had? Those of us who are old enough will recall when we had the same kind of standard-of-care discussions about pulse oximetry, end-tidal CO2 monitoring, and the use of ultrasound for central lines. Perhaps COVID-19 simply will push us sooner toward video laryngoscopy for everyone.

Aerosol generation?

Here’s a question: Is routine airway management in the operating room, under controlled conditions, really the same in terms of aerosol generation as airway management in the ED or the ICU? Does it make sense to treat them as equivalent?

Imagine that we have a patient who is afebrile and asymptomatic, with a negative COVID-19 test result documented within 48 hours. We are preparing for a routine surgical or diagnostic procedure. We preoxygenate and administer an hypnotic agent and NMB. Assuming a good mask seal and easy ventilation, what quantity of aerosolized respiratory secretions actually would escape into the air? What is the real risk of coronavirus transmission?

Intubating this patient, who is completely paralyzed, should generate no coughing at all. It’s completely different from approaching the critically ill patient in the ED or ICU with a high viral load, who is likely to be coughing relentlessly and receiving high-flow oxygen. Similarly, smooth extubation of the normal surgical patient should produce little or no coughing, and minimal aerosol generation. It’s still reasonable, if you wish, to wear higher-level personal protective equipment (PPE) than the simple surgical mask and eye protection we wore before COVID-19, but the practical risk seems far less, and wearing full head-to-toe PPE seems wasteful.

The “post-aerosol pause” – a waiting period after intubation and extubation before allowing personnel in or out of the operating room – is meant to allow time for air exchange to clear the air of contaminants. Should it be done only for patients with confirmed or suspected COVID-19, or expanded to all patients, given the risk of asymptomatic infection and false-negative tests? The time required to remove airborne contaminants varies with the room’s air exchange rate per hour. The pause would need to last 14 minutes to achieve 99 per cent removal in a room with 20 air exchanges per hour, or as long as 46 minutes if there are only 6 exchanges per hour. Now that elective surgery is ramping up again, production pressure and sheer human impatience has buried the post-aerosol pause except for urgent cases in patients with proven or suspected COVID-19.

Will we ever get back to “normal”?

No one knows the answer. Writing today, I suspect that many anesthesia professionals may be wearing N95 masks for intubation, extubation, bronchoscopy, and upper endoscopy (including TEE) for a long time to come, even after the pandemic is over. It’s hard to walk back PPE recommendations, or eliminate worry about some new lung pathogen yet to come.

As long as we don’t let fear stand in the way of common sense, or let donning and doffing PPE distract us from patient care, we can make productive use of some lessons learned from COVID-19. But how we think about  airway management may never be quite the same.

Author’s note: This article was written in May 2020 for the American Society of Anesthesiologists’ monthly magazine, the ASA Monitor. It was published online ahead of print on June 29, 2020.

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Selected references:

Warters RD, Szabo TA, Spinale FG, DeSantis SM, Reves JG. The effect of neuromuscular blockade on mask ventilation. Anaesthesia 2011; 66:163-167. DOI: https://doi.org/10.1111/j.1365-2044.2010.06601.x 

Sachdeva R, Kannan TR, Mendonca C, Patteril M. Evaluation of changes in tidal volume during mask ventilation following administration of neuromuscular blocking drugs. Anaesthesia 2019; 69:826-831. https://doi.org/10.1111/anae.12677

Priebe HJ. Another nail in the coffin of the practice of checking mask ventilation before administration of a muscle relaxant. Anesth Analg 2019; 129(3):e103-e104. doi: 10.1213/ANE.0000000000004260

Broomhead RH, Marks RJ, Ayton P. Confirmation of the ability to ventilate by facemask before the administration of neuromuscular blocker: a non-instrumental piece of information? British Journal of Anaesthesia 2010; 104(3): 313-317. https://doi.org/10.1093/bja/aep380

Kheterpal S, Martin L, Shanks AM, Tremper KK. Prediction and outcomes of impossible mask ventilation. A review of 50,000 anesthetics. Anesthesiology 2009; 110: 891–897. https://doi.org/10.1097/ALN.0b013e31819b5b87

Orser B. Recommendations for endotracheal intubation of COVID-19 patients. Anesth Analg 2020; 130(5):1109-1110. DOI: 10.1213/ANE.0000000000004803

ASA and APSF Joint Statement on Perioperative Testing for the COVID-19 Virus. Online publication April 29,2020. https://www.apsf.org/news-updates/asa-and-apsf-joint-statement-on-perioperative-testing-for-the-covid-19-virus/ [Accessed April 30, 2020]

Infectious Diseases Society of America Guidelines on Infection Prevention in Patients with Suspected or Known COVID-19. Online publication April 27, 2020. https://www.idsociety.org/practice-guideline/covid-19-guideline-infection-prevention/ [Accessed April 30, 2020]

Anesi GL. Coronavirus disease 2010 (COVID-19): Critical care issues. UpToDate online publication, last updated April 24, 2020. https://www.uptodate.com/contents/coronavirus-disease-2019-covid-19-critical-care-issues?source=related_link#H3884198318 [Accessed April 30, 2020]

Rajappa GC, Parate LH, Tejesh CA, Prathima PT. Comparison of modified chin lift technique with EC technique for mask ventilation in adult apneic patients. Anesth Essays Res 2016; 10(3):643-648. doi: 10.4103/0259-1162.191111

Wald SH, Arthofer R, Semple AK, Bhorik A, Lu AC. Determination of length of time for “post-aerosol pause” for patients under investigation or positive for COVID-19. Anesth Analg 2020; published ahead of print April 28, 2020. https://journals.lww.com/anesthesia-analgesia/Citation/9000/Determination_of_Length_of_Time_for__Post_Aerosol.95646.aspx [Accessed April 29, 2020]

Sibert K, Long J, Haddy S. Extubation and the Risks of Coughing and Laryngospasm in the Era of Coronavirus Disease-19 (COVID-19). Online publication at Cureus.com, May 19, 2020. https://www.cureus.com/articles/31997-extubation-and-the-risks-of-coughing-and-laryngospasm-in-the-era-of-coronavirus-disease-19-covid-19

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