[cnn-photo-caption image= http://i2.cdn.turner.com/cnn/2009/images/08/06/art.cooling.blanket.cnn.jpg caption="Therapeutic hypothermia patients receive a chilled saline solution and are put under a cooling pad or blanket."]
PHILADELPHIA, Pennsylvania (CNN) - Seated on a jetliner, Dr. Mary Gallagher and her husband, Don Dietrich, were about to take off for an anniversary vacation in Puerto Rico. But a glance at her husband of five years set off an alarm - he was gasping for breath. Gallagher, an anesthesiologist, knew the signs: Dietrich was in cardiac arrest.
Gallagher ran to tell the pilot; someone called 911 from a cell phone; another passenger started CPR. Paramedics appeared and then Gallagher made a crucial decision: Even though protocol called for Dietrich to be taken to the nearest hospital, three miles away, she insisted he go twice as far, to the University of Pennsylvania Hospital and its Center for Resuscitation Science.
By the time Dietrich hit the emergency room, he had a weak pulse. At most hospitals, standard treatment is to sit tight and hope for the best. But at UPenn, doctors hooked Dietrich to an intravenous line of chilled saline solution, dropping his body temperature to a cool 91 degrees.
More than 90 percent of people who suffer cardiac arrest, as Dietrich did, end up dying. For more than a decade, there has been evidence that cooling a patient's body - or therapeutic hypothermia - improves those odds. No one quite knows why, but it's thought that the cold reduces the body's need for oxygen and slows the deadly chemical cascade that sets in when oxygen isn't circulating because the heart stopped beating.
Yet, as one 2007 paper put it, "implementation of hypothermia is lousy." In 2006, researchers at the University of Chicago found that just 34 percent of critical care physicians, and just 16 percent of emergency physicians, had ever attempted to use hypothermia to treat cardiac arrest. Makers of cooling equipment say fewer than 300 hospitals, out of more than 6,000 nationwide, have the necessary equipment.