From the Catholic Herald:
Pope Francis’s primary doctor during his hospitalisation has said it was the Pope himself who chose to keep trying different therapies when his life was most at risk, and has also attributed the pontiff’s “miraculous” recovery, in part, to prayer. Speaking to Italian journalist Fiorenza Sarzanini with Italy’s newspaper of record, Corriere della Sera, Doctor Sergio Alfieri said the night of Feb. 28 was “the worst” night of the Pope’s five-week-long ordeal.
That day the Pope experienced a bronchospasm: when the muscles lining the bronchi (the tubes that connect the windpipe to the lungs) constrict and narrow, limiting the amount of oxygen the body receives.
