evidence: The reason: Some hospitals have reported unusually high death rates for coronavirus patients on ventilators, and some doctors worry that the machines could be harming certain patients. [...] Mechanical ventilators push oxygen into patients whose lungs are failing. Using the machines involves sedating a patient and sticking a tube into the throat. Deaths in such sick patients are common, no matter the reason they need the breathing help. Generally speaking, 40 percent to 50 percent of patients with severe respiratory distress die while on ventilators, experts say. But 80 percent or more of coronavirus patients placed on the machines in New York City have died, state and city officials say.