This month there has been a revolution among New York doctors in understanding how to treat severe coronavirus cases, with the potential for significantly lowering the Infection Fatality Rate from whatever it has been in earlier months. Emergency rooms are now advised to be less in a rush to ventilate patients with low percentages of oxygen in their blood. Conversely, people at home with coronavirus symptoms are advised to check their oxygen with a simple pulse oximeter device rather that wait to seek help until they can hardly breathe.
iSteve commenter SimpleSong writes:
One caveat–as anyone who works in healthcare can tell you, if you put on a pulse oximeter and it’s not getting a good signal, it will often basically become a random number generator. So you may have a lot of false positives with this.
Bad signals take a bit of expertise to troubleshoot, it can be you don’t have it on properly, or your hands are extremely cold and have poor circulation, or you are wearing nail polish (even clear nail polish can screw up the signal because it uses infrared as well as visible), or you put it on too large a finger or too small a finger. Anesthesiologists are always screwing with these things during cases, probably more than any other monitor, and they have the really high end ones. So you might get a lot of false positives with this.
However if you feel sick or you know you have coronavirus and you are weighing whether to go in to the hospital, the false positives are probably worth it.
Second aside: respiratory phys is interesting–you need your lungs for two things, to eliminate carbon dioxide and absorb oxygen, but the drive to breathe is solely from carbon dioxide levels. The feeling of suffocation or shortness of breath is caused by CO2 alone (specifically, high CO2). If you breathe an atmosphere of pure nitrogen you will feel perfectly fine for a few seconds, then immediately die. On the other hand an atmosphere of 10% CO2 and 20% oxygen will make you feel like you are suffocating, possibly induce a panic attack, but nevertheless could probably be breathed indefinitely.
Third aside: if the best treatment for this turns out to be oxygenation, that is very, very good news. Because the atmosphere is only 20% oxygen is pretty easy to improve oxygenation, just crank that up to 100% oxygen and now each breath delivers five times as much oxygen. This is technically easy to do and doesn’t require intubation or a ventilator. A 4 dollar non-rebreathing facemask can get you well above 50% and basically anybody can use it. Heck people with COPD spend years with nasal cannulae and oxygen generators managing their disease at home.
Ventilators are required primarily for CO2 elimination (although they also help with oxygenation). While it’s easy to increase the oxygen that is inhaled with simple passive measures like facemasks, to get rid of more CO2, you just have to breathe, no other option, so if the patient can’t do it you need the vent, with all the complexities and risks associated with that.