Maximal tachycardia and high cardiac strain during night shifts of emergency physicians
To compare tachycardia and cardiac strain between 24-hour shifts (24hS) and 14-hour night shifts (14hS) in emergency physicians (EPs), and to investigate key factors influencing tachycardia and cardiac strain.
We monitored heart rate (HR) with Holter-ECG in a shift-randomized trial comparing a 24hS, a 14hS, and a control day, within a potential for 19 EPs. We also measured 24-h HR the third day (D3) after both shifts. We measured perceived stress by visual analog scale and the number of life-and-death emergencies.
The 17 EPs completing the whole protocol reached maximal HR (180.9 ± 6.9 bpm) during both shifts. Minutes of tachycardia >100 bpm were higher in 24hS (208.3 ± 63.8) than in any other days (14hS: 142.3 ± 36.9; D3/14hS: 64.8 ± 31.4; D3/24hS: 57.6 ± 19.1; control day: 39.2 ± 11.6 min, p < .05). Shifts induced a cardiac strain twice higher than in days not involving patients contact. Each life-and-death emergency enhanced 26 min of tachycardia ≥100 bpm (p < .001), 7 min ≥ 110 bpm (p < .001), 2 min ≥ 120 bpm (p < .001) and 19 min of cardiac strain ≥30% (p = .014). Stress was associated with greater duration of tachycardia ≥100, 110 and 120 bpm, and of cardiac strain ≥30% (p < .001).
We demonstrated several incidences of maximal HR during shifts combined with a high cardiac strain. Duration of tachycardia were the highest in 24hS and lasted several hours. Such values are comparable to those of workers exposed to high physical demanding tasks or heat. Therefore, we suggest that EPs limit their exposure to 24hS. We, furthermore, demonstrated benefits of HR monitoring for identifying stressful events.
ClinicalTrials.gov identifier: NCT01874704.
KeywordsOccupation Work Heart rate Stress Death Sleep Relative cardiac cost Strain
Body mass index
Relative cardiac cost
Visual analog scale
We express our sincere gratitude to all emergency physicians of the Department of the Emergency Department of the University Hospital of Clermont-Ferrand, France, who participated in this study.
FD has participated as main investigator. FD, GB, CP, AC and JS contributed to the conception of the protocol. FD, GB and FM contributed to data analysis. FD and FM drafted the manuscript. All authors revised the manuscript and added substantial inputs. All authors read and approved the final manuscript. FD and FM takes responsibility for the integrity of the data analysis.
Compliance with ethical standards
This work was funded by the Association of Emergency Physician of Clermont-Ferrand (ASMUC). The funding source had no role in the design, conduct, or reporting of the study.
Conflict of interest
The authors declare that they have no competing interests.
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