A study published in Annals of Surgery monitored surgical residents’ fatigue levels during a 24-hour shift using eye movement metrics, objective measures of laparoscopic surgical performance, and subjective reports based on standardised questionnaires. According to the authors, prior attempts to investigate the effects of fatigue on surgical performance have suffered from methodological limitations. However, they wrote, because saccadic velocity is involuntary, a fatigue index based on saccadic velocity could potentially provide an accurate and unbiased measure of the resident’s fatigue level.
The researchers measured eye movements of six males and six females from a general surgery resident team over their 24-hour shift using a head-mounted video eye tracker. Surgeons performed two simulated laparoscopic surgery tasks and a guided saccade task, before and after their shift. Additionally, they rated their perceived fatigue level throughout their shift using a standardised scale.
The researchers concluded, “time-on-duty decreased saccadic velocity and increased subjective fatigue but did not affect laparoscopic performance. These results support the hypothesis that saccadic indices reflect graded changes in fatigue. They also indicate that fatigue due to prolonged time-on-duty does not result necessarily in medical error, highlighting the complicated relationship among continuity of care, patient safety, and fatigued providers”. The findings could impact the development of neuroergonomic tools to detect fatigue and future guidelines regarding residents’ duty hours.