Effects of intraoperative breaks on mental and somatic operator fatigue: a randomized clinical trial



Intermittent work breaks are common in fields with high workload but not yet for surgeons during operations. We evaluated the effects of intraoperative breaks during complex laparoscopic surgery (5 min every half hour) on the surgeon.


Fifty-one operations were randomized to a scheme with intraoperative breaks and release of the pneumoperitoneum (intermittent pneumoperitoneum (IPP)) or conventional conduct (CPP). Stress hormones and α-amylase were determined in the surgeon’s saliva pre-, intra-, and postoperatively. Mental performance and error scores, musculoskeletal strain, and continuous ECG were secondary endpoints.


Regular intraoperative breaks did not prolong the operation (IPP vs. CPP group: 176 vs. 180 min, p > 0.05). The surgeon’s cortisol levels during the operation were reduced by 22 ± 10.3% in the IPP vs. the CPP group (p < 0.05). There were significantly fewer (p < 0.05) intraoperative events in the IPP vs. the CPP group, which yielded higher α-amylase peaks. The pre- to postoperative increase in the error rates of the bp-concentration test was fourfold reduced in the IPP group (p = 0.052). The relevant locomotive strain-scores were grossly reduced by IPP (p < 0.001).


Our data support the idea that work breaks during complex laparoscopic surgery can reduce psychological stress and preserve performance without prolongation of the operation time compared with the traditional work scheme.

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  1. 1.

    Correction factor for complexity (cf): Mean results for every procedure were referenced to the most abundant operation in this series (pyeloplasty, which was assigned the factor 1.0).

    \( {\text{Cf}} = {\frac{{{\text{over}}\;{\text{all}}\;{\text{mean}}\;{\text{duration}}_{{({\text{operation}}\;{\text{type}})}} }}{{{\text{over}}\;{\text{all}}\;{\text{mean}}\;{\text{duration}}_{\text{pyeloplasty}} }}} \)

    \( \Upsigma {\text{cf}}_{{{\text{IPP}}\;{\text{or}}\;{\text{CPP - group}}}} /n_{{{\text{operations}}\;{\text{IPP}}\;{\text{or}}\;{\text{CPP}}\;{\text{group}}}} = {\text{mean}}\;{\text{cf}}_{{{\text{ IPP}}\;{\text{or}}\;{\text{CPP}}\;{\text{group}}}} \)

    \( {\text{mean}}\;{\text{cf}}_{{{\text{ IPP}}\;{\text{or}}\;{\text{CPP}}\;{\text{group}}}} \times {\text{mean}}\;{\text{duration}}_{{{\text{IPP}}\;{\text{or}}\;{\text{CPP}}\;{\text{group}}}} = {\text{corrected}}\;{\text{duration }} \)


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We thank D. Auge and A. Osthaus, MHH for expert help with ECG systems and cardiac output determination, Dr. Judith Orsanu from NASA’s Ames research center in California for discussion, and Prof. R. Dietrich, Humbold University Berlin/Germany for information on simultaneous translation and Mr. Bill Groundwater, Kirkwall/Orkney for help with the manuscript.


This study was financed from the Hannover Medical School general health care budget. Drs. Engelmann, Schneider, Dingemann, Schoof, Ure, and Professors Kirschbaum and Grote have no conflicts of interest or financial ties to disclose.

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Correspondence to Carsten Engelmann.

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Engelmann, C., Schneider, M., Kirschbaum, C. et al. Effects of intraoperative breaks on mental and somatic operator fatigue: a randomized clinical trial. Surg Endosc 25, 1245–1250 (2011). https://doi.org/10.1007/s00464-010-1350-1

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  • Intermittent pneumoperitoneum
  • Work breaks
  • Complex laparoscopic surgery
  • Stress hormones
  • Concentration–error performance