Evaluating nursing performance during heatwave simulations: Protocol for a repeated measures cross-over study

This study protocol combines clinical simulations with climatic chamber experiments, to evaluate 1) the impact of heat stress on hospital nurses' physiological strain, physical and mental fatigue, vigilance, and clinical performance; and 2) the efficacy of a practical cooling intervention (i.e., electric fan) in mitigating the negative impact of heat stress. UK-based, registered adult nurses working in hospital settings will be recruited to partake in a repeated-measures cross-over design study, consisting of five separate 3-hour experimental sessions simulating clinical work, and taking place within a climatic chamber at Southampton General Hospital (UK). Sessions will differ by ambient temperature and cooling intervention as follows: 1) control (CTR; 18°C, 50% relative humidity [RH]); 2) warm (WARM; 26°C, 50%RH); 3) warm with electric fan (WARM+FAN; 26°C, 50%RH); 4) hot (HOT; 34°C, 50%RH); 5) hot with electric fan (HOT + FAN; 34°C, 50%RH). This study has been registered on a publicly accessible clinical trial registry (ISRCTN45793399). During each session, participants will first complete a standardised fatigue-induction protocol simulating shift work (i.e., low-intensity cycling with cognitive tasks); followed by a simulated hospital ward round involving six simulated patients and two simulated cardiac arrest scenarios. Nursing cognitive and physical performance will be assessed using a standardised observational assessment battery, along with objective cardiopulmonary resuscitation (CPR) performance metrics. Physiological responses will be assessed by monitoring changes in core temperature (Tcore), skin temperature (Tskin), heart rate, and whole-body sweat loss (WBSL). Fatigue and vigilance will be measured using the Swedish Occupational Fatigue Inventory (SOFI) and Brief Psychomotor Vigilance Task (PVT-B), respectively. Baseline (i.e., prior to fatiguing protocol) to post simulation changes in 1) vigilance assessed via the PVT-B (i.e., a determinant of role-specific cognitive performance); 2) CPR quality score (i.e., a determinant of role-specific physical performance); and 3) Tcore (i.e., a determinant of thermo-physiological state); will be analysed using linear mixed models to determine the effects of ambient temperature and cooling intervention on nurses' clinical and physiological performance. By providing a controlled methodological framework for assessing the effects of heat exposure on hospital nurses' physiological, perceptual, and clinical performance, this study will provide empirical evidence on air temperature-related changes in nursing performance and physiological strain and the role of cooling interventions in modifying these responses. This will support the development of evidence-based climate adaptation strategies to protect healthcare staff wellbeing and maintain patient safety during periods of extreme heat.