For example, surgical complications can arise hours after an operation is completed.
"I believe that a patient is better off with a fatigued resident who is able to handle a postsurgical catastrophe because he was present at the surgery and knew what the surgical concerns were, than to have a rested resident who doesn't know the patient," said Dr. Joseph Fischer, surgeon in chief at Boston's Beth Israel Deaconess Hospital. He said a proper backup system -- with a more experienced surgeon -- is important when surgical residents work long hours.
When work shifts are shortened, patient handoffs -- transfer of patient care from one doctor to another -- occur more frequently.
"I've seen many errors, and actually a few patient deaths, that are due to the improper handoff of patient care," said Dr. Ben Musher at the University of Pennsylvania. "There is a trend toward residents not thinking of patients as their own because residency is becoming like shift work."
However, many residents believe they are asked to work marathon hours for other reasons.
"The reason residents are pushed to work these excessively long shifts is that they are considered cheap labor in a for-profit system of health care that is constantly pushed to its very limits to cover its ever-growing costs," said Terranella.
Since this is the largest study to date showing that marathon work hours contribute to patient harm -- including patient deaths -- patients may want to know how long their doctor has been working continuously.
"Patients have a right to know and to refuse care if the doctor has been awake for more than 24 hours," Czeisler said. "These data suggest that this is a human rights issue, because patients have never consented to these gravely increased risks."
"Who would knowingly put themselves in the hands of a doctor who had been awake and on the job for more than 24 hours?" said Terranella.
"You wouldn't choose to fly with a pilot under those circumstances, so why is it acceptable to let a surgeon cut into you?"
"Coming to work impaired for any reason is not acceptable," said Dr. Steven Howard, director of the Patient Safety Center of Inquiry at the Stanford University School of Medicine. "How do we change our society's culture to prioritize rest so that we can be optimally prepared to work?"
Some physicians have suggested better patient handoffs and longer residencies may be necessary.
"The challenges now are how to have healthy, safe, rested trainees that are well trained at the end of their training period," said Howard.
And experts said this study has important implications for patient safety and the current state of residency training.
"These data demonstrate that the standard practice of scheduling young doctors to work marathon shifts lasting 30 consecutive hours twice a week during their training presents a grave risk to the patients with whose care they are entrusted," said Czeisler.
The study discussed in this article can be accessed here.