Some patients, by taking oxygen and rolling onto their sides or on their bellies, have quickly returned to normal levels. The tactic is called proning.
[...]
At Lincoln Hospital in the Bronx, Dr. Nicholas Caputo followed 50 patients who arrived with low oxygen levels between 69 and 85 percent (95 is normal). After five minutes of proning, they had improved to a mean of 94 percent. Over the next 24 hours, nearly three-quarters were able to avoid intubation; 13 needed ventilators. Proning does not seem to work as well in older patients, a number of doctors said.
No one knows yet if this will be a lasting remedy, Dr. Caputo said, but if he could go back to early March, he would advise himself and others: “Don’t jump to intubation.”
[...]
Dr. Josh Farkas, who specializes in pulmonary and critical care medicine at the University of Vermont, said the risks of proning were low. “This is a simple technique which is safe and fairly easy to do,” Dr. Farkas said. “I started doing this some years ago in occasional patients, but never imagined that it would become this widespread and useful.”
Some more on proning in this NYT article: