The FAA requires that all major commercial U.S. airlines have on board medical kits that include an automated external defibrillator (AED), which can be used to shock the heart back to normal rhythm.
Medications in the on-board kits must include a non-narcotic pain killer; IV fluids for dehydration or low blood pressure; an antihistamine to treat allergic reactions; an inhaler for asthma; aspirin and nitroglycerin for a heart attack; IV dextrose for low blood sugar; epinephrine for allergic reactions or asthma; and atropine, and lidocaine as an adjunct to CPR. The kits must also contain a stethoscope and a manual blood pressure cuff among other supplies.
Martin-Gill concedes that some airlines are better equipped than others. One relatively common occurrence is nausea and vomiting and his study showed that the rate of diversion is lower when nausea medicine is available.
But he argues, "The vast majority of emergencies can be handled well with the equipment on board. In our experience, the kits cover most of the situations encountered on the aircraft."
Right now all three major airline associations are working with medical experts to revise recommendations for those kits.
One, the Aerospace Medical Association, hopes to have new guidelines ready for 2014. The last review was in 2003, according to Executive Director Jeffrey Sventek.
The organization advises the airline industry on medical emergencies and provides online publications for the lay person who has questions about their medical condition before they travel.
"We have got to do something because we feel very responsible to the public to provide a safe and healthy environment," said Sventek. "Americans are doing a lot more international travel and are exposed to more infectious diseases. There are myriad issues surfacing because of our mobile population."
He said the association "didn't disagree" with Gounder's observations that doctors sometimes need more expertise when volunteering on a flight.
"Not every doctor is trained in every specialty -- very few are," Sventek said. "You throw them inside an aircraft and with individuals with different circumstances."
"Some medical kits are lacking or some doctors didn't know there were experts on the ground made available through radio communication," said Sventek.
But, he adds, "Frankly, I think the airlines do a pretty good job of it," he said. "Medical folks who step forward to volunteer do a tremendous job."
Dr. Michael Gerardi, a former flight surgeon and pilot who is now director of pediatric emergency medicine at Morristown Medical Center in New Jersey, said every time he takes a flight, he identifies himself and tells the crew not to be afraid to wake him if there is an emergency.
"Emergency physicians rush to the patient on planes when these things occur," he said. "It is our nature, our DNA, and we are masters of improvisation."
He said emergencies happen when people with pre-existing medical conditions ignore their symptoms in anticipation of a flight.
"They get a maybe a TIA ( transient ischemic attack) or chest discomfort," he said. "It's a trip of a lifetime and they've got to get to that wedding. They don't eat or don't sleep and worry about the TSA lines and neglect their symptoms. Something is prone to happen."
Alcohol and use of sedatives to sleep can also cause medical problems, he said.
Sometimes doctors on board who have sub-specialties are hesitant to help out, said Gerardi. "They are totally out of their environment and feel the liability or risk, even with the good Samaritan laws. And if a patient dies, there is paperwork. They put a blanket or pillow over their head."
Still, Gerardi concedes, the medical kits are "pretty Spartan."
He agrees with Gounder that in addition to broader IV capabilities, the airlines should have a glucometer to measure blood sugar and access to sedatives.
"You see people go bizarre on airplanes," he said. "It would be good if we could knock them out and put them to sleep. … People with psychiatric issues need not be duct-taped to a chair."
Gounder said while most doctors are happy to assist, they are on vacation, too.
"In some ways, it's not fair," she said. "They are relying on our good will. And it's not just our good will -- it's an imposition."
One of her colleagues flew from Sri Lanka through London and almost missed a connecting flight because she was helping a passenger in distress. "She almost missed her connection and it was a big deal. ... We give [our help] because it is our duty and responsibility to care."
In the very least, Gounder said she wished she had known there were ground-based medical services the flight attendants could have contacted to help her deal with some of the passengers she volunteered to help. And maybe a little more positive reinforcement.
"One of the flight attendants on a flight from India to Frankfurt gave me a bottle of champagne," she said. "What am I supposed to do, drink the entire bottle before I go through customs? It didn't make any sense.
"It would have been nice to get a meaningful thank you letter -- recognition of what you did and an update."