Blood pressure dipping and salivary cortisol as markers of fatigue and sleep deprivation in staff anesthesiologists

Abstract

Anesthesiologists often work extended duty shifts that result in acute and chronic sleep loss and circadian disruption. Stress caused by sleep deprivation, together with excessive workload could contribute to acute increases in blood pressure (BP) and sympathetic nervous system activity. Non-dipping pattern of BP is considered an additional risk factor for cardiovascular events and target organ damage. We hypothesized that there would be significant changes of cardiovascular parameters when comparing work on call during the 24-hour in-hospital shift (24-HD) versus ordinary working day (8-HD) combined with changes of dipping pattern and altered diurnal cortisol secretion, measured by salivary cortisol (SC). Following local Medical Ethics Committee approval, 12 out of 36 staff anesthesiologists (8 male, 4 female), 33-61 years old, participated in this study. Ambulatory BP monitor was used for noninvasive 24-hour ambulatory BP and heart rate (HR) monitoring. Each participant was monitored continuously during the 8-HD, as well as during the 24-HD. Saliva for analysis of cortisol levels was collected six times a day (at 8 am, 11 am, 2 pm, 5pm, 8pm, and 11 pm) both during 8-HD and on 24-HD. There was a significant decrease in number of diastolic dippers on call vs. diastolic dippers on ordinary working day (4/12 vs. 10/12, p=0.036), and non significant decrease of systolic dippers (3/12 vs. 7/12, p =0.214). There were no significant differences in SC values between 8-HD and 24-HD at all observed time points. However, the SC values measured during the night were markedly elevated on both days compared with reference values and the shapes of SC curves were altered. The lack of diastolic BP dipping could be more sensitive indicator of stress among staff anesthesiologists than systolic BP dipping. The shape of SC diurnal curve in terms of elevated night values could be another indicator of their chronic fatigue.