My lede:

“Oh, I forgot all about that,” Monal Joshi, MD, responded to a question from a senior resident during morning report. The internal medicine intern, entering the 25th hour of a 30-hour shift at Rush University Medical Center in Chicago, had overlooked a patient’s test result.

The slip was quickly caught by a supervisor, and no harm was done. But was the resident’s momentary lapse due to fatigue?

Dr. Joshi had at least two hours of sleep the night before — pretty good for when she’s on call.

Some other members of the five-person Rush internal medicine residency team looked worse for wear as their shifts neared the end one day last spring. Third-year medical student Shikha Wadhwani rested her hand on her head, blinking slowly and yawning widely, as the others went through their reports.

But Yoojin Kim, MD, an intern who slept from 3:30 a.m. to 6 a.m., looked bright as a fluorescent light as she sped through her patient reports.

Sleep scientists say staying awake for more than 16 hours decreases the ability to concentrate, impairs memory and hinders the ability to do tasks such as tracking test results on a monitor.

Yet sleep deprivation does not affect everyone the same way. Such is the enigma of the debate on whether resident duty-hour limits have helped patients.

Six years have passed since the Accreditation Council for Graduate Medical Education cut resident workweeks to 80 hours. The council also restricted shifts to 24 hours of call plus six hours of patient transition and educational activities.

Some health leaders said cutting back the weekend-long shifts and 120-hour workweeks that were common before the 2003 rules would yield a safety benefit — fewer patient deaths and fewer complications. But it is hard to make a definitive, evidence-based argument that the work-hour limits have improved patient outcomes, experts said.

The whole shebang.