Quantification of surgical residents’ stress on-call

Abstract

Introduction. Surgical resident stress includes psychological and physiological components which relate linearly to heart rate (HR), oxygen consumption (VO 2), and neutrophil demargination. The purposes of this series of experiments were (1) To relate HR to VO 2 in surgical residents during exercise; (2) to monitor HR as a measure of stress on call; (3) to relate maximum HR on call by surgical resident training level; and (4) to monitor white blood cell (WBC) count as a measure of stress during call. Methods. HR and VO 2 were monitored in surgeons ( n = 5) during bicycle ergometry. HR was continuously monitored (Holter) for 24 h on call for interns ( n = 6), and junior ( n = 5) and chief residents ( n = 5). WBC counts were obtained from residents off and on call ( n = 6). Results. HR (72 ± 5 to 124 ± 4 BPM) correlates with VO 2 (273 ± 24 to 1535 ± 103 mlO 2/min) R 2 = 0.843. Control maximal HR was 110 ± 3. Compared to controls, on call maximal HR was elevated for interns and junior residents to 149 ± 6 ( P = 0.0003) and 136 ± 6 ( P = 0.009), respectively, but was unchanged in chief residents at 116 ± 3 ( P = 0.5). There were no 1-h time periods during which the HR was above 120 bpm in controls. This number of 1-h time periods increased to 7 ± 1 in the interns ( P = 0.01) and 6 ± 3 in the junior residents ( P = 0.03), but was unchanged in senior residents, 0.4 ± 0.2 ( P = 0.8). WBC increased from 5.7 ± 0.4 to on call values of 7.2 ± 0.6 (p = 0.04). Neutrophils decreased from 58 to 49% ( P = 0.005). This was offset by an increase in lymphocytes from 33 to 40% ( P = 0.009). Conclusion. We conclude that HR correlates with VO 2 as an objective measure of stress. Surgical residents achieve stress levels of tachycardia during on-call periods that inversely reflect the training level of the residents. Phenotypic change was documented as an increase in leukocyte count. The stress of being “on call” is substantial enough to provoke measurable physiologic and phenotypic changes in surgery residents.