We’ve all heard of people turning up at a hospital, in these times and any other time, “at death’s door”.
What you might not have heard of, until now, is people turning up at hospitals who…. should be dead already, according to the best medical science. But that’s happening, apparently, and it’s one of a few incredible things in this mind-blowing article published in the American journal “Stat”:
Even as hospitals and governors raise the alarm about a shortage of ventilators, some critical care physicians are questioning the widespread use of the breathing machines for Covid-19 patients, saying that large numbers of patients could instead be treated with less intensive respiratory support.
If the iconoclasts are right, putting coronavirus patients on ventilators could be of little benefit to many and even harmful to some.
What’s driving this reassessment is a baffling observation about Covid-19: Many patients have blood oxygen levels so low they should be dead. But they’re not gasping for air, their hearts aren’t racing, and their brains show no signs of blinking off from lack of oxygen.
That is making critical care physicians suspect that blood levels of oxygen, which for decades have driven decisions about breathing support for patients with pneumonia and acute respiratory distress, might be misleading them about how to care for those with Covid-19. In particular, more and more are concerned about the use of intubation and mechanical ventilators. They argue that more patients could receive simpler, noninvasive respiratory support, such as the breathing masks used in sleep apnea, at least to start with and maybe for the duration of the illness.
For reasons of fairness, we won’t quote it all, though we’d really like to. If you’re a Coronavirus news junkie, go and read the whole thing. It’s about the most interesting thing published about the illness in several weeks.
If you don’t have time, though, here’s a summary.
Basically, there have been reports lately on the wires that, for all the hype about ventilators as last hope of coronavirus patients, the people who are placed on them fare terribly. An Italian doctor claimed that only 20 percent of patients he saw who were subjected to them recovered. A small study in Wuhan had a success rate of three in 22.
The explanation for the poor success rate seemed obvious: If you’re sick enough with COVID to require artificial respiration, you’re very far gone. Chances are you’re not coming back from the brink, ventilator or no ventilator.
But the article in Stat raises a new, much more frightening proposition: What if ventilation isn’t failing because it’s too late for the patient, but because ventilation is actually making things worse?
Normally when a patient has a low blood oxygen level, it means their lungs are failing and they need a machine to breathe for them. With some coronavirus patients, though, the lungs aren’t failing. They’re absorbing less oxygen — but they’re still successfully removing most carbon dioxide, avoiding a critical situation. Their condition is more akin to altitude sickness, says Stat, than to pneumonia. When a patient’s lungs are functioning reasonably well, you don’t want to intubate them and put them on a machine. The machine can do damage of its own, especially among older patients. Here’s one more exerpt, just because it’s important:
In acute respiratory distress syndrome, which results from immune cells ravaging the lungs and kills many Covid-19 patients, the air sacs of the lungs become filled with a gummy yellow fluid. “That limits oxygen transfer from the lungs to the blood even when a machine pumps in oxygen,” Gillick said.
As patients go downhill, protocols developed for other respiratory conditions call for increasing the force with which a ventilator delivers oxygen, the amount of oxygen, or the rate of delivery, she explained. But if oxygen can’t cross into the blood from the lungs in the first place, those measures, especially greater force, may prove harmful. High levels of oxygen impair the lung’s air sacs, while high pressure to force in more oxygen damages the lungs.
In a letter last week in the American Journal of Respiratory and Critical Care Medicine, researchers in Germany and Italy said their Covid-19 patients were unlike any others with acute respiratory distress. Their lungs are relatively elastic (“compliant”), a sign of health “in sharp contrast to expectations for severe ARDS.” Their low blood oxygen might result from things that ventilators don’t fix. Such patients need “the lowest possible [air pressure] and gentle ventilation,” they said, arguing against increasing the pressure even if blood oxygen levels remain low. “We need to be patient.”…
Because U.S. data on treating Covid-19 patients are nearly nonexistent, health care workers are flying blind when it comes to caring for such confounding patients. But anecdotally, Weingart said, “we’ve had a number of people who improved and got off CPAP or high flow [nasal cannulas] who would have been tubed 100 out of 100 times in the past.” What he calls “this knee-jerk response” of putting people on ventilators if their blood oxygen levels remain low with noninvasive devices “is really bad. … I think these patients do much, much worse on the ventilator.”
What’s the alternative?
Well, basically, they seem to have found that in many (though by no means all) cases, simply providing oxygen at a gentle level into the nasal cavity works better, because it doesn’t alter the pressure in the lungs.
But there’s a problem with that: Someone getting oxygen into their nose is breathing out normally, which means they’re breathing out the virus, which means that they’re paradoxically a much greater risk to the doctors and nurses treating them.
If these guys are right, that’s very good news on one level, because it will ease the demand for ventilators.
But it’s bad news on another level, because we still have a shortage of masks.
Anyway, read the whole thing. Those guys are much smarter than me.