Call-associated acute fatigue in surgical residents--subjective perception or objective fact? A cross-sectional observational study to examine the influence of fatigue on surgical performance.

BACKGROUND

The effect of acute partial sleep deprivation on surgical proficiency is still controversially discussed. The present study correlated physiological parameters of fatigue with objective technical and cognitive skills, as well as subjective sleepiness of surgical residents. The aim of the study was to assess the effect of acute partial sleep deprivation on surgical performance.

METHODS

Thirty-eight surgeons were interviewed on three consecutive mornings: prior to a 24 h call, post-call, and after 24 h of rest. Reported hours of sleep were recorded. Subjective alertness was assessed with the standardized Stanford-Sleepiness-Scale (SSS). Saliva cortisol concentrations and pupillary activity were measured by standardized ELISA and pupillography. The virtual reality (VR)-simulator LapSim was used to assess technical skills through low-fidelity VR-tasks ("cutting," "clip applying") and cognitive skills through high-fidelity VR-tasks ("intracorporeal suturing," "VR-cholecystectomy"). Objective alertness was measured by the standardized d2-Paper-Pencil Test.

RESULTS

Recorded hours of sleep (p = 0.001) and subjective alertness (SSS) decreased (p = 0.001) significantly post-call. None of the three factors studied-saliva cortisol concentration (p = 0.313), pupillary activity (p = 0.998), or VR-performance of low-fidelity VR-tasks-differed significantly between assessments. Surprisingly, VR-performance of high-fidelity VR-tasks (error-score p = 0.044, time to complete task p = 0.0001, economy of instrument motion p = 0.0001) and objective alertness (d2-Paper-Pencil Test p = 0.027) significantly improved in the post-call setting.

CONCLUSIONS

Acute call-associated fatigue seems to be a predominantly subjective perception. Physiological factors seem to outbalance an anticipated fatigue-associated impairment of technical performances within low-fidelity VR-tasks. In surgical residents, acute partial sleep deprivation seems to have a positive short-term effect on cognitive skills, leading to enhanced technical performance and increased objective alertness within complex tasks.