Background: Surgical skills and decision making are influenced by alertness, reaction time, eye-hand coordination, and concentration. Night shift might impair these functions but it is unclear to what extent. The aim of this study was to investigate whether a night shift routinely impairs the surgeon's fitness to perform and whether this reaches a critical limit as compared to relevant frames of reference.
Methods: Consultants (n = 59) and residents (n = 103) conducted fitness to perform measurements at precall, postcall, and noncall moments. This validated self-test consists of an adaptive tracker that is able to objectively measure alertness, reaction time, concentration, and eye-hand coordination, and multiple visual analog scales to subjectively score alertness. Results are compared to sociolegal (ethanol) and professional (operative skills) frames of reference that refer to a decrease under the influence of 0.06% ethanol.
Results: Residents spent 1.7 call hours asleep on average as compared to 5.4 for consultants. Subjective alertness decreased in residents after night shifts (-13, P < 0.001) but not in consultants (-1.2, P = NS). The overnight difference in tracker score was -1.17 (P < 0.001) for residents and 0.46 (P = NS) for surgeons. Postcall subjective alertness only correlated to objective alertness in consultants. For residents, hours slept on-call correlated to objective alertness. For consultants, subsequent night calls significantly correlated to objective alertness, with the third subsequent call related to performance below the reference.
Conclusions: Consultants remain fit to perform after night call, but subsequent calls may compromise clinical activities. This study provides insight and awareness of individual performance with clear frames of reference.