24 hours on-call and acute fatigue no longer worsen resident mood under the 80-hour work week regulations.

PURPOSE: Studies in on-call residents have shown that mood is worsened by fatigue as indicated by increased scores on measures of depression, anxiety, confusion, and anger using the Profile of Mood States (POMS). In prior sleep deprivation studies, mood has been shown to be more affected than either cognitive or motor performances. The purpose of this study was to examine the effect of the 80-hour work week regulations on resident mood in general and in a post-call period (PC).
METHODS: Institutional Review Board approval was obtained to survey the residents and publish the results. POMS is a 65-item adjective questionnaire that includes subscales for measuring tension-anxiety, anger-hostility, depression-dejection, vigor-activity, fatigue-inertia, and confusion-bewilderment, with the summation of the scales forming a total mood disturbance score. Surgical residents were tested at a 9 am didactic curriculum session (9 am has been shown to correlate with the nadir of performance). Residents were tested after nights off call (NOC) or after PC. Time asleep in the preceding 24 hours and other demographic data were also collected. Acute fatigue (AF) was defined as <4 hours sleep. The two-sample t-test and linear regression were used to assess differences between groups.
RESULTS: A total of 123 standardized POMS mood questionnaires were administered on 4 occasions to 51 surgical residents, 35 men and 16 women at levels PGY-1 through PGY-5. Overall, 33 tests (27%) were taken after PC and 90 (73%) were taken after NOC. Acute fatigue residents had a mean sleep time of 2.2 (+/-1.5) hours, whereas rested (R) residents had a mean sleep time of 6.7 (+/-2.2) hours (whether PC or NOC). No statistical differences in mean values of vigor, anger, depression, concentration, fatigue, tension, or total score were observed between PC and NOC or between AF and R residents. There was no significant relationship between acute sleep deprivation and total mood disturbance, whether PC or NOC. In linear relationships, NOC total score and hours slept had r2 = 0.01 (p = 0.44), whereas PC total score and hours slept had r2 = 0.07 (p = 0.14).
CONCLUSION: Although POMS was given 4 times, only 27% were PC, which reflects our 1 in 4 night in-house coverage. In contrast to earlier studies, resident mood, as measured by POMS, is no longer related to PC/NOC or acute fatigue. Previous studies have shown that loss of sleep was associated with declining mood. The lack of such a relationship in this study may be related to the new regulations. It has been assumed that people can adapt to chronic sleep loss but have a harder time coping with the effects of acute sleep deprivation. If, however, the new regulations have relieved chronic sleep deprivation, then a well-rested resident can periodically cope with the effects of acute sleep deprivation. Perhaps by eliminating chronic sleep debt, work hour restrictions seem to have removed the negative impact of PC seen in the prior era. Further studies should increase the number of residents studied, have numerous repeat NOC and PC pairs in same subjects, compare different services with different workloads, junior and senior residents, and in-house and at-home call schedules.