After staying up all night to care for ailing patients, medical interns who drive home from the hospital at the end of a marathon shift become a threat to themselves and to the commuting public, according to a study published in today's New England Journal of Medicine.
Researchers found that interns more than doubled their risk of getting into a car accident after being on call, a stint that meant working for 32 consecutive hours with only two or three hours of sleep, on average. Interns were also nearly six times as likely to report nearly having an accident on their way home.
The report is the latest in a series of studies by researchers at Harvard Medical School and Brigham and Women's Hospital in Boston that aim to quantify the dangers of requiring doctors to work long shifts with little rest. The researchers say that working for more than 24 hours causes interns to make serious medical errors and poses a public safety hazard.
In the latest study, the researchers followed 2,554 interns during their first year of training, when they logged an average of 71 hours a week. The interns reported a total of 320 motor vehicle crashes, 40% of which occurred as they drove home from the hospital.
Extrapolating from those results, sleepy interns across the country are involved in more than 23,000 car crashes each year, said study coauthor Charles Czeisler, the chief of sleep medicine at Brigham and Women's Hospital.
"These 30-hour shifts are dangerous for patients, they're dangerous for physicians and they're dangerous to other motorists," Czeisler said.
Barbie Gatton, a third-year resident in emergency medicine at Methodist Hospital in Brooklyn, N.Y., said the study's conclusions were distressing -- and obvious -- to most interns.
"We went into this business to ease suffering and to heal the sick, and the last thing you want to be are the people who are the public safety hazard," said Gatton, who is president of the Committee of Interns and Residents, a labor union that represents 12,000 doctors in the U.S.
The union and others are pressing for federal legislation that would limit the number of hours doctors-in-training may work. Current guidelines set by the Accreditation Council for Graduate Medical Education limit interns and residents to an average of 80 hours a week, with no shift exceeding 30 hours.
The researchers say those limits don't give doctors enough time to sleep. A study published last fall, also in the New England Journal, found that interns who spent every third night working in the intensive care unit made 36% more medical errors than interns who kept less onerous schedules. They also made serious diagnostic errors 5.6 times as often as their well-rested counterparts, the study found.
Studies have shown that being awake for 21 hours impairs drivers as much as having a blood-alcohol concentration of 0.08, which is the legal limit for noncommercial drivers in the U.S., said Dennis Wylie, a consultant who analyzes human factors in motor vehicle operation and wrote an editorial accompanying today's study.
"It stands to reason that working for 32 hours would be worse," Wylie said.
But paring back the 80-hour work week would translate into longer residency programs if doctors are to complete the same amount of overall training, said Peter Carmel, a neurosurgeon and trustee of the American Medical Assn.
More important, it would mean finding money to pay for additional interns and residents. Neither Medicare -- which funds resident salaries -- nor hospitals have the resources, he said. Alternatives, such as nurses or physician assistants, are even more costly than residents, who typically earn $40,000 a year.
"Who's going to pay the additional salaries?" Carmel said. "That is going to be an extremely expensive choice for the public."