May 1, 2012

The results of a study published this month in the American Journal of Surgery will certainly strike some of us as counterintuitive. The researchers looked at the effect of sleep deprivation on surgical residents and found that sleepiness does not affect performance of a previously learned task. For patients at Portland hospitals, the broad implication is that the surgeon with just two hours of sleep is no more likely to make a mistake than the well-rested surgeon.

The study did not involve surgery on patients. Rather, the medical students used a simulator. On the first day, they practiced for about 45 minutes on all three levels of a particular task. They all got a good night’s sleep and came back on the second day. They performed the same tasks to get a baseline score. The researchers tossed in another task during the test to determine how well the subjects dealt with unexpected events.

That night, half of the students got another good night’s sleep while the other half slept for just two hours. On the third day, they all took the same test. They also learned a different task and were tested on that; the researchers wanted to find out if lack of sleep would have any effect on learning something new.

Surprisingly, the sleep-deprived subjects performed as well as the well-rested. The only difference was how hard their brains had to work: For the sleep-deprived, the same test results took more effort. This “cognitive workload” has been the subject of other studies.

And we’ll go into that more in our next post.

Source: Penn State Hershey, “Sleepiness may affect surgeons’ ability to deal with the unexpected,” May 2012


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