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Do ventilators work?

April 20, 2020

Humans, 

I want to clear some stuff up about ventilators. I’ve seen the narrative that ventilators don’t work. This is typically coming from non-medical people and discussed in non-medical ways so I want to clarify the point and explain where this comment and confusion is coming from. 

Ventilators do work. They can help the lungs function normally when the lungs are not meeting the demands of the body. There are two distinct things ventilators do for us. They help ventilate (move air in and out) and they help oxygenate (add oxygen to the body). We put people on ventilators when they have impending respiratory failure. Respiratory failure is when the body dies because of a primary respiratory problem. 

If it is a ventilation problem, then the effort to breathe has become so difficult and tiresome that the person can no longer move enough air. Think of running a sprint that you can never stop running - eventually, you would die. If it is an oxygenation problem, then your lungs have become too sick to get enough oxygen from the air it is breathing. Think of being put into a small airtight room with no source of oxygen - eventually, you would die. 

Crash course in understanding lung physiology… check.

Here is the rub. How do you predict when someone is about to have or is in the process of having respiratory failure. We typically like to figure this out before death. OK, I’m going to really simplify this. If someone is about to have respiratory failure from a ventilation problem, they look like they have been running a marathon. We make the decision clinically based on their work of breathing, how long they have been working like that, and what their mental state is. If someone is about to have respiratory failure from an oxygenation problem, they look like they are being starved for air. We make the decision based on their oxygen saturation (O2Sat) which is a rough indicator of how much oxygen is in their blood. Any number below 95 is abnormal and any number below 80 is really abnormal. 

Crash course in respiratory failure… check.

Here is the deal, for some reason COVID patients are coming in with very, very, very, very low O2Sats. Like way less than 80%. ER docs in NY and New Jersey are reportedly seeing people walk in with Sats in the 70s, or 60s, or 50s, or even in the 40s. Normally when you see those numbers, it means impending death and a ventilator is what is needed to save the patient’s life.  But, with COVID patients, their clinical picture and their O2Sat don’t appear to be telling the same story. One NY ER doc was quoted as saying, “I have never before had to tell a patient to get off the phone in order to emergently put them on a ventilator.”

We do not know exactly why this disease causes such low oxygenation levels. And perhaps more perplexing is the number of patients who have these crazy low O2Sats that end up getting better simply by treating with supplemental oxygen.  This is achieved with tubes in the nose (nasal cannula), a mask that can deliver even more oxygen, or CPAP (a device similar to the one people use to treat sleep apnea at home). So, doctors are now hypothesizing that perhaps putting people on the ventilator “too” early may be causing more harm than good. We just don’t know yet. Please refer to my other emails that continue the mantra that we need time to figure this disease out. We will figure it out, no question, but we need time. 

Anyway, I know the medical folks that read this will point out that this is a huge oversimplification But, for the non-medical crowd, this gives a framework for understanding a bit more on the debate on ventilators. We may have caught a lucky break. Fewer patients requiring mechanical ventilation mean less need for ventilators and therefore less concern for the ventilator shortage we anticipated. 

So here is the take-home, if you need a ventilator and you don’t get one, you will die. Thankfully, doctors are trained to recognize when you need a ventilator before you die. With time and experience, doctors are learning more about this disease. This includes how COVID patients differ from those suffering from other types of respiratory illnesses to include how they can tolerate lower oxygen levels and when is the best time to place them on ventilators

Crash course in ventilators and COVID… check.

Stay emotionally connected and physically distant,

Greg

PS: If you want to read more about the ventilators and COVID this article from Time and this one from US News are good. 

PPS: A lot of COVID patients are having kidney issues and are needing dialysis. So keep an eye out for the decision on whether we have enough dialysis machines next.