Ventilators can save lives in the most severe cases of the coronavirus, but new research indicates doctors may overuse the medical technique and harm their patients. Some 50 percent of people diagnosed with COVID-19 and placed on ventilators die, and damage caused by the machine may account for some of those deaths, according to a study published on April 21 in the American Journal of Tropical Medicine and Hygiene.
The National Institutes of Health released guidelines on April 21 that encourage doctors to start with less invasive breathing support, like nasal cannulas. If mechanical ventilation becomes necessary, the NIH recommends delivering only low volumes of oxygen.
Physicians have clung to tried-and-true treatment methods typically used for pneumonia patients, but COVID-19 affects people differently than other types of viral pneumonia. “There is mounting evidence that lots of patients are tolerating fairly extreme” low levels of oxygen in the blood, suggesting less need for a ventilator, Muriel Gillick of Harvard Medical School, told Stat.
Patients with other types of pneumonia typically gasp for breath and can barely speak when their oxygen saturation level—a measure of how well their blood is oxygenated—drops below 90 percent. But at even much lower oxygen levels, COVID-19 patients can often speak in full sentences without getting winded and show no signs of respiratory distress.
Unlike with other viral types of pneumonia, areas of healthy, elastic lung tissue can sit right next to damaged areas in those with COVID-19. Forcing high-pressure oxygen-enriched air into elastic tissue in large volumes can cause tissue leaks, swelling, and inflammation and can result in increased mortality, the researchers wrote. —J.B.