The effect of acute sleep deprivation and fatigue in cardiovascular perfusion students: a mixed methods study.

Sleep deprivation as a result of long working hours has been associated with an increased risk of adverse events in healthcare professions but not in cardiovascular perfusion. The purpose of this study is to investigate the impact of sleep deprivation on cardiovascular perfusion students. Testing with high-fidelity simulation after 24 hours of sleep deprivation allowed investigators to assess user competency and the effect of fatigue on performance. After informed consent, seven senior perfusion students were enrolled in the study (three declined to participate). The qualitative portion of the study included a focus group session, whereas the quantitative portion included administration of questionnaires, including the Epworth Sleepiness Scale (ESS) and the Stanford Sleepiness Scale (SSS), as well as clinical skills assessment using high-fidelity simulation. Subjects were assessed at three different intervals of sleep deprivation over a 24-hour period: baseline (6:00 AM), 12 hours (6:00 PM), 16 hours (10:00 PM), and 24 hours (6:00 AM) of wakefulness. During each scenario, normally monitored bypass parameters, including mean arterial pressure, activated clotting times, partial pressures of oxygen, partial pressures of carbon dioxide, and venous flow, were manipulated, and the subjects were required to return the parameters to normal levels. In addition, the scenario required calculation of the final protamine dose (using a dose-response curve) and detection of electrocardiography changes. Each task was varied at the different simulation sessions to decrease the effect of learning. Despite any lack of sleep, we hypothesized that, because of repetition, the times to complete the task would decrease at each session. We also hypothesized that the ESS and SSS scores would increase over time. We expected that the students would anticipate which tasks were being evaluated and would react more quickly. The average ESS scores progressively increased at each time period: baseline, 12 hours, 16 hours, and 24 hours. At 24 hours, the ESS and SSS scores were the greatest and the standard deviation was low, suggesting that fatigue affected all participants. During the clinical task evaluations, a "flattening effect" on the learning curve over time was observed. Tasks that required a higher level of cognition had prolonged completion times. Sleep deprivation significantly affects clinical performance as assessed with high-fidelity simulation. To optimize patient and clinician safety, it is important that the question of length of working time be investigated further.