Sleep deprivation can worsen clinical performance. Early studies on the effects of fatigue in clinical trainees formed some of the basis behind duty hour restrictions for resident physicians. This study surveyed intensive care unit (ICU) nurses about levels of fatigue and clinical decision-making. Nurses who regretted a clinical decision were more apt to be fatigued and to work 12-hour shifts. Sleep deprivation among ICU nurses was found to be common, with almost three-quarters of surveyed nurses having lost 8 or more hours of sleep in a 5-day period. The study was limited by a very low (17%) response rate, potentially biasing the results. Prior research has linked extended nursing shift lengths with compromised patient safety.