As alluded to yesterday, probably the most glaring difference is that, unlike an airplane, each patient is unique. If a pilot sits at the controls of any Airbus A320 aircraft, he can be reasonably sure that pulling back the stick a certain amount will result in a very consistent response from the plane. Therefore, practicing on a simulator will enable the pilot to prepare for any emergency with the knowledge that what he did on the simulator will in fact be reproducible in a real emergency.
Contrast that with a patient. Often patients with similar illnesses will behave very differently because human beings are not engineered like airplanes. For example, let’s say I am performing a difficult laparoscopic cholecystectomy (removal of the gallbladder) and I am having trouble locating the cystic artery (artery to the gallbladder). I know that the anatomy of the cystic artery is highly variable. This link illustrates 11 of the most common anatomic variations in the location of that vessel. This means that there is not a simple maneuver that will help me find the artery in every case.
A pilot can be confident that a 5% increase in power will result in a very predictable response in airspeed. Contrast that with a patient’s response to a medication. I have had patients fall asleep with an intravenous injection of only 2 mg of morphine and I’ve had other patients who loudly complain of persistent pain after receiving 10 mg of the same drug.
A word about simulators. Because all stimuli are external to a fixed object, the pilot, aircraft simulators are easy to design and are very realistic. They recreate the motion, sounds and visuals of flying very well. When I was in the Navy stationed on an aircraft carrier, I heard pilots talk about their experiences in simulators. They said the intensity of the experience was very similar to that of flying a real plane. While surgical simulators have become more sophisticated, they still lack the realism of aircraft simulators because the action is all occurring on a video screen and the surgeon is sitting in a lab somewhere. There is no way that a surgical simulator can give you the adrenaline rush and anal sphincter-puckering feeling of seeing a sudden squirt of blood that covers your laparoscope and totally obscures your vision during a tough case. And there are no realistic surgical simulators for open (non-laparoscopic) cases. Operating on a pig just doesn’t cut it. (Pun intended.)
So please, stop trying to compare patients to airplanes.
A postscript on yesterday’s “Surgeons Are Not Pilots” blog.
Captain Chesley Sullenberger, the appropriately acclaimed hero of the successful Hudson River landing of US Airways Flight 1549, is hardly a typical pilot. According to one biography, he had over 27,000 hours of flying experience with more than 19,000 of those hours in Airbus A320s or like aircraft. He also had written about air safety and worked as an NTSB investigator. The hours alone qualified him as an “expert” pilot.
Compare Sully’s background with that of the pilots of Colgan Air Flight 3407, which crashed in Buffalo two years ago, killing 50 people. The following is from the Wikipedia entry about this incident, “The crew of four was led by Captain Marvin Renslow … who was hired by Colgan in 2005 and had flown 3,379 hours. 261 of these hours were on the Dash-8 Q400 (including 109 as a captain). First Officer Rebecca Lynne Shaw … was hired by Colgan in January 2008, and had flown 2,200 hours, 772 of them on the Q400.” The cause of the fatal accident was several pilot errors and failures to follow protocols.
All the checklists in the world didn’t prevent that crash. As long as humans are going to perform surgery on other humans, bad outcomes will occur. Yes, we should endeavor to minimize errors as much as possible, but “zero defects” and Six Sigma are not possible in medicine (or even in manufacturing).