I lie on a stretcher, thinking of my two sons. They are both healthy, in Philadelphia and Manhattan. Seven months before, we suffered through the death of their mother — my wife of 37 years. She wanted to live so badly. After an 18-month battle with cancer, she left us.

The three of us have gotten closer since her death, but I know I am no replacement. After 12 days of living with the coronavirus, I admitted myself to the Emergency Department.

I know too much about this illness. I know that my oxygen saturation plummeting the night before is a sign of advanced pulmonary disease with Covid-19 infection. I know that I might need a mechanical ventilator — I have given this therapy to strangers hundreds of times.

On March 9, the pandemic still seemed far away. Nobody had gotten ill yet. I attended the last large emergency management system meeting of the Northwell health system in Manhasset, N.Y., where we discussed supply procurement and personnel coverage for the coming pandemic. I drove back to my office in the Cohen Children’s Medical Center in nearby New Hyde Park.