Dynamics and association of different acute stress markers with performance during a simulated resuscitation

Aim: Whether mental stress negatively impacts team performance during cardio-pulmonary resuscitation (CPR) remains controversial; this may partly be explained by differences in stress measures used in previous studies. Our aim was to compare self-reported, biochemical and physiological stress measures in regard to CPR performance.

Methods: This prospective, observational study was conducted at the simulator center of the University Hospital Basel, Switzerland. Self-reported (feeling stressed and overwhelmed [stress/overload]), biochemical (plasma cortisol) and physiological (heart rate, heart rate variability) stress measures were assessed in 28 residents (teams of 2) before, during and after resuscitation. Team performance was defined as time to start CPR and hands-on time during the first 180 s.

Results: At baseline, significant negative correlations of heart rate variability with stress/overload and heart rate, as well as positive correlations of heart rate and cortisol were found. During resuscitation, self-reported, biochemical and physiological stress measures did not correlate significantly. There was no association of baseline stress measures with performance. During CPR, stress/overload was significantly associated with time to start CPR (regression coefficient 12.01 (95% CI 0.65, 23.36), p=0.04), while heart rate was negatively associated with time to start CPR (regression coefficient -0.78 (95% CI -1.44, -0.11), p=0.027) and positively with hands-on time (regression coefficient 2.22 (95% CI 0.53, 3.92), p=0.015).

Conclusions: Self-reported stress (stress/overload) was the only predictor for low CPR performance. Biochemical measures showed no association, and physiological measures (heart rate) showed an inverse association, which may be due to physical activity, limiting its value as a mental stress marker in this acute setting.