(Apologies to Mike - we usually don't like to step on each other on the blog, but I missed he'd just published another great post!  So don't miss it here!)

So this week, the reality of what's coming started to dawn on many at the medical center. As we start moving from the preparation to the treatment phase of the pandemic, more people have been pulled into the realities of caring for suspected and confirmed COVID patients . . . and stories abound from around the U.S. about how a lot of them have some very strong opinions about PPE:  A healthcare worker who showed up to work in full Ebola gear (no, I'm sure the co-workers felt safe in their "flimsy" masks).  Entire units who mandated masking of everyone after a co-worker was diagnosed with COVID (and had not worked with symptoms).  The sudden interest in and expertise about asymptomatic transmission by folks who never worried about coming to work sick with other viruses before.  Adding to the confusion are the contradicting images (full Tyvek suits in China), messages (a Power Point describing Wuhan experiences that notes SARS-CoV-2 can spread "through eyelashes and hair"), and, sadly, guidance from various authorities:

  • OSHA: "Those who work closely with (either in contact with or within 6 feet of) patients known to be, or suspected of being, infected with SARS-CoV-2, the virus that causes COVID-19, should wear respirators."
  • CDC: First, the recommended protection included a respirator for all types of patient care.  Then this was revised to: "Put on a respirator or facemask (if a respirator is not available) before entry into the patient room or care area. N95 respirators or respirators that offer a higher level of protection should be used instead of a facemask when performing or present for an aerosol-generating procedure. . .When the supply chain is restored, facilities with a respiratory protection program should return to use of respirators for patients with known or suspected COVID-19."
  • WHO, Canadian Health Authority, and an increasing number of state health departments, including Tennessee:  Gown, gloves, facemask, eye protection (goggles or face shield) unless performing an aerosol-generating procedure, and then use a respirator or PAPR instead of the mask.

I definitely understand and support the need to be cautious, especially when it's early in a new pathogen outbreak, and the protection and safety of healthcare personnel (HCP) has been a major concern of mine and the focus of my career.  But one can easily see how the seeds of confusion have been sown among our HCPs regarding PPE.

No issue has been the bane of my work this week than "aerosol-generating procedures" or AGPs, and as I tried to dive into the science behind these recs, I came away even more confused.  A few quick learnings and thoughts on this issue:
  • The term "aerosol" means a very different thing to a true aerosol scientist (whom I imagine I will offend with much of my own ignorance here) and most lay medical people:  To the former, an aerosol is a smaller particle (smaller than a droplet), the smallest of which require a higher level of filtration to protect HCP (as in a respirator).  To the latter, any visible drop of fluid, liquid, spit, etc. is an "aerosol" ("I can see it flying through the air!!"), and as such their perception is that the official lists (more on those in a bit) of AGPs are lacking.  
  • The various lists of what might be an AGP vary by organization and even changes within a single organization's guidance.  Some include nebulized medications. Some, like WHO, had nebs on one version of the list in 2007 but removed them in 2009. A brief summary below:
  • The actual science on what is an AGP and, more importantly, whether they confer a higher risk of transmission of infectious agents is a) very difficult to illustrate (often relying on retrospective recall of patient care activities in infected and non-infected HCP), b) involves some logistically challenging studies (ask Dr. Babcock), and c) has many confounding factors (individual patient issues, use of PPE, etc.).  I refer you to a few excellent papers on the topic HERE and HERE (shout out to our favorite blogger!).  Also see this nice summary in the lay press HERE
I imagine, if we all shared our lists of AGPs, there'd be wide disagreement (which is why I didn't tell you mine). Some will have nebulized medications (which always throws the peds clinics into a frenzy). Some don't.  CPAP/Bipap?  Maybe, but the few studies that have examined this often just say "non-invasive ventilation," and 1 study in SARS had a single patient infect 22 HCPs as a driver of that risk.  Is nighttime Bipap setting on the vent the same as rescue Bipap in impending respiratory failure (where there may be more suctioning and bagging of the airway?).  Open suctioning of the airway?  Just try to find any further description of that generic and broad term in any of the guidelines or evidence base. Is a brief (few seconds), pharyngeal suction an AGP? Is it really similar in risk to a deep, persistent need to suction copious lower airway secretions? Clearly no, but they're all "open suction of the airways." I think what we're seeing is that a simple term or list of procedures that is provided in guidance without strong evidence or out of an abundance of caution can have major logistic and psychological impact when trying to implement on the front line.  Also, without more clarity (and more funded science on this topic!), we end up potentially using valuable PPE that was not warranted if no risk exists. 

I'll end by saying, sadly, this is not the first time we've dealt with this issue. For those of us who were hosp epis during the H1N1 pandemic, this exact conversation occurred, albeit with less intensity as the wave of illness didn’t flood the hospitals as much as expected. Our frontline healthcare workers are putting themselves at potential risk by caring for these patients, and they are understandably anxious and scared. Conflicted and confusing PPE recs do them no service, and guidance not rooted in science that leads to inappropriate use of PPE may lead to shortages down the road and more exposed HCP. This pandemic has already started, but perhaps we can finally learn and have more funded science to provide clarity and consistency on these issues that account for the real world nuances of delivery of healthcare. Failure to do so merely puts our HCP at greater risk for the next new pathogen.


  1. Great post, Tom. The poor people on the frontline are so confused as we have been forced to revise our recommendations repeatedly due to changing guidance and the problems caused by PPE shortages. We now include a header on each new communication: This guidance supersedes all previous guidance.


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