The two doctors and an off-duty United Airlines pilot were among the 161 people aboard the flight. The off-duty pilot aided the first officer — who is also a trained pilot — in landing the plane while the physicians performed CPR.
The doctors who helped the pilot were from Madigan Army Medical Center, said Jay Ebbeson, public affairs officer for the hospital at Joint Base Lewis-McChord.
Glenn Harmon, an aerospace physiologist who was an airline pilot for nine years before becoming a professor at Embry-Riddle Aeronautical University, said all commercial airline pilots undergo a medical screening every six months to keep their certification with the FAA.
That screening typically includes a test to measure heart function called an EKG, Harmon said, but the test doesn’t necessarily pick up every condition.
Sometimes, the in-flight environment can have a small impact on pre-existing medical conditions, Harmon said. The air on a flight is dry, usually at between 10 or 20 percent humidity, and that can contribute to dehydration.
“One thing that happens to us as pilots is we might be dehydrated and not know it,” Harmon said. “We don’t like to guzzle lots of water because it’s so complicated now to get up and leave the cockpit to go to the bathroom.”
Sitting in a cramped seating position for long periods can lead to deep vein thrombosis, or clots deep inside the body. Passengers can get up from their seats and move around to help prevent DVT, but pilots don’t get the same opportunity, Harmon said.
The cabin pressure also has a slight effect on blood oxygen levels.
Flight crews train for medical emergencies, and most airlines subscribe to a service that puts them in immediate radio contact with a doctor on the ground in case of emergencies. Additionally, all commercial flights have a first officer onboard who is trained to fly the plane in addition to the pilot. There’s often a third, off-duty pilot flying to or from work who can help in an emergency.
Even the biggest commercial aircrafts can generally be flown and landed by just one pilot, Harmon said.
Associated Press writer Doug Esser in Seattle contributed to this report.