Are the "Vent Protocols" causing harm in COVID?

Here is a response to Deborah Mayo's excellent blog post posing this question.  I encourage you to first read her post.  Here, I explicate my view of the problems that are raised in that post.  I don't have time for a lot of hot links and stuff, so post your specific comments below.

There is a lot correct here, and @learnfromerror has done a far better job of summarizing it than I could ever explain a normal distribution. But there is a lot missing, because the commentators have not gotten to the crux, and have made slogans for their points that are distracting and misguided if not totallly incorrect.

First, and this is very very important, is that *there are NO protocols for intubation* as the NYC ER doctor suggests. I talk about that on my other blog a lot. ARDS trials enroll patients who are *already intubated* and the criteria for that intubation are absent from the study protocols. It is assumed in an ARDS study that if you are intubated, you were appropriately intubated. Therefore, there is no “problem with the protocols” for ventilators, there is a glaring and longstanding problem with the criteria (or the absence of criteria) for intubating patients. Is it blood gas values, or vital signs, or physical examination signs, or subjective distress or some combination? There is ZERO standardization in this area. COVID has brought this underappreciated problem to the fore.

Why is this just coming out now? Ah, that’s another crux of the problem and a reason that COVID has become a perfect storm for ventilator management. Usually, if you intubate a little old lady with influenza, even if you do it for shaky reasons, she can be extubated (tube removed) in a couple of days or a week with little harm done (or with a level of harm that we take for granted, probably mistakenly). Not so with COVID. The natural history of the disease has 2 important features that make the decision to intubate likely to culminate in a massive therapeutic misadventure: 1.) the duration of the illness is protracted, two to perhaps as long as four weeks; and 2.) the level of sedation needed to counteract the massive air hunger these patients have, for the duration they need it, is through the roof.  This problem is compounded by the mandate to use small tidal volumes which are poorly tolerated in the face of massive air hunger. So, 2 weeks after intubation, they are veritable zombies, cannot be weaned from sedatives (a prerequisite from being weaned from the ventilator), and are stuck on the vent, assuming that before this stage other complications have not set in and/or death ensued.

Another facet of the perfect storm, which I think is also the Rosetta Stone, and a key to untangling this giant mess we find ourselves in, is that this normal lung compliance that people are talking about is *the reason why* there is this so-called “silent hypoxemia” of the type mentioned by the ER doc in Mayo’s post. Failure to recognize this connection betrays a common misunderstanding of respiratory physiology (my attempt to disabuse people of these errors can be found here: https://pulmccm.org/ards-review/great-lecture-applied-respiratory-physiology/). Dyspnea is not driven by hypoxemia as much as it is by hypercarbia, which can be compensated for by hyperventilation which these patients are doing! To a person who has a firm grasp on applied respiratory physiology, this is no surprise – the patients have compliant lungs, so they don’t have workload imbalance and can sustain ventilation in the face of significant hypoxemia (which is a MINOR driver of dyspnea) very well. In sum, I am not surprised by these clinical presentations, nor am I surprised that this quagmire has allowed problems with the understanding of applied respiratory physiology to surface.

This disease is very difficult for these and many other reasons. When the choice is let a hypoxemic person who is defending her CO2 - like the little old lady the ER doc talks about - ride it out (which she can probably do for a very long time, see my tweets about sustaining very high Ve indefinitely [50% of the 15-second MVV]), versus intubating her for a marginal gain in gas exchange accompanied by a massive cost in sedation and paralysis, the choice is clear, let them ride it out, don't incur that cost.

The problem is not with the “vent protocols” the problem lies in a widespread lack of understanding of applied respiratory physiology which leads to questionable calls regarding intubation which are usually, in non-pandemic times, lost in the signal and noise of the fray. Not so with COVID – premature or unnecessary intubations precipitate a cascade of status iatrogenicus.

Book Smarts and Common Sense in Medicine - Why Highly Intelligent People Make Bad Decisions

In the presentation on Epistemic Problems in Medicine on the Medical Evidence Blog, I begin by highlighting the difference between intelligence (book smarts) and rationality (common sense).  Oftentimes thought to be one and the same, they are distinctly different, and understanding failures of common sense among very intelligent people can illuminate many problems that we see in medicine, several of which have been highlighted on this blog.

Intelligence is the ability of the mind to function algorithmically, like a computer.  Intelligent people are good at learning, through rote memorization, rules that can be applied to solve well defined problems.  They are also good at pattern recognition which allows them to recognize a problem type to know which rule applies to it.  This kind of intelligence is very precisely measured by IQ tests.  It is correlated with scores on college entrance exams like the ACT and SAT and with other entrance tests such as MCAT.  Of course, intelligent people need to devote the time to learn the rules to answer the questions on these tests which measure both aptitude and achievement.

Rationality, I think, is more closely aligned to the notion of common sense and it shows very little significant correlation to IQ in any domain in which it has been investigated.  Cognitive psychologists talk about two kinds of rationality.  The first is how well a person's beliefs map onto reality (the actual structure of the world), and it has been termed epistemic rationality (sometimes also called theoretical or evidential rationality).  Persons with epistemic rationality have beliefs that are congruent with the world around them and which are strong in proportion to the strength of the evidence supporting them.  Thus a physician who believes that bloodletting or mercury therapy cures disease in the 21st century would be considered to have suboptimal epistemic rationality, as would a person whose fear of Hantavirus while hiking in New Mexico is grossly disproportionate to the actual statistical risk.

Parsimonious Practice: How to Treat DKA with 5 Lines of Orders in Half a Day

Few processes in medicine are as simple as the treatment of DKA (diabetic ketoacidosis) or have been as gratuitously complicated by anal retentive micromanagers of physiology.  Here is a departure from that custom that I have refined iteratively during the past four years.  It is guided by the goal of reversing ketoacidosis (and associated dehydration) and getting patients eating and back on subcutaneous insulin as expeditiously as possible, while reducing waste and burdens of care and without compromising safety.  It does not have as a goal to rigidly govern lab values or usurp control of physiology during the process.  The caveat to be aware of is that I have refined it in young(ish), adult, non-compliant Type I diabetics without insulin resistance who have moderate to severe acidosis and hyperglycemia.  (I do not treat "DKA" with a serum HCO3- greater than or equal to 14 with an insulin infusion - I treat it with fluids and reinstitution of subcutaneous insulin.)  It also presumes that there was no trigger other than non-compliance, or that the trigger (e.g. UTI) has been investigated and addressed.  I will briefly discuss the 5 orders, their benefits and potential drawbacks.  First, the orders:

1.)  Bolus with 5 liters of Lactated Ringers Solution

2.)  Begin insulin infusion at 5 units per hour (FIXED DOSE, NO BOLUS, NO TITRATION).

3.)  Check blood sugar every 2 hours; When blood sugar less than 200 mg/dL, reduce insulin drip to 1 unit per hour.

4.)  If blood sugar is less than 100 mg/dL (on any insulin dose) or greater than 300 mg/dL on 1 unit per hour, call MD.

5.)  Check serum K+ and HCO3- 12 hours after the start of treatment.