In the Bible, Lazarus is raised from the dead by Jesus. In medicine, Lazarus is the patient who, believed dead, spontaneously starts to circulate blood.

About 40 cases of the Lazarus phenomenon, a number that experts believe is too small to be valid, have been reported in the medical literature. (I have seen at least three cases in my own career.) Though most patients died soon after the event, in eight cases they left the hospital, neurological functions intact. The cases share a kind of morbidity: A man, eighty, is pronounced dead after thirty minutes of CPR. His doctor showers and returns five minutes later to find his patient has a pulse. A man, eighty-four, goes into cardiac arrest while biking. After fifteen minutes of CPR he is pronounced dead and taken to a mortuary, where attendants see him breathing. A woman, sixty-eight, suffers a heart attack and goes into prolonged cardiac arrest. Removed from her ventilator, she is taken to a separate room, where about twenty minutes later a nurse notes she is breathing and moving under the sheet. She is discharged from the hospital and dies three months later in her sleep.

Why are certain deaths “reversible”? The phenomenon remains a mystery. Some have speculated that cessation of CPR decreases pressure in the chest cavity, allowing blood to return to the heart.