Sex difference and intra-operative tidal volume Insights from the LAS VEGAS study

Nijbroek S. F., Hol L., Swart P., Hemmes S. N. T., Neto A. S., Binnekade J. M., ...More

EUROPEAN JOURNAL OF ANAESTHESIOLOGY, vol.38, no.10, pp.1034-1041, 2021 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 38 Issue: 10
  • Publication Date: 2021
  • Doi Number: 10.1097/eja.0000000000001476
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, BIOSIS, CINAHL, EMBASE, MEDLINE
  • Page Numbers: pp.1034-1041
  • Dokuz Eylül University Affiliated: Yes


BACKGROUND One key element of lung-protective ventilation is the use of a low tidal volume (V-T). A sex difference in use of low tidal volume ventilation (LTVV) has been described in critically ill ICU patients. OBJECTIVES The aim of this study was to determine whether a sex difference in use of LTVV also exists in operating room patients, and if present what factors drive this difference. DESIGN, PATIENTS AND SETTING This is a posthoc analysis of LAS VEGAS, a 1-week worldwide observational study in adults requiring intra-operative ventilation during general anaesthesia for surgery in 146 hospitals in 29 countries. MAIN OUTCOME MEASURES Women and men were compared with respect to use of LTVV, defined as V-T of 8 ml kg(-1) or less predicted bodyweight (PBW). A V-T was deemed 'default' if the set V-T was a round number. A mediation analysis assessed which factors may explain the sex difference in use of LTVV during intra-operative ventilation. RESULTS This analysis includes 9864 patients, of whom 5425 (55%) were women. A default V-T was often set, both in women and men; mode V-T was 500 ml. Median [IQR] V-T was higher in women than in men (8.6 [7.7 to 9.6] vs. 7.6 [6.8 to 8.4] ml kg(-1) PBW, P < 0.001). Compared with men, women were twice as likely not to receive LTVV [68.8 vs. 36.0%; relative risk ratio 2.1 (95% CI 1.9 to 2.1), P < 0.001]. In the mediation analysis, patients' height and actual body weight (ABW) explained 81 and 18% of the sex difference in use of LTVV, respectively; it was not explained by the use of a default V-T. CONCLUSION In this worldwide cohort of patients receiving intra-operative ventilation during general anaesthesia for surgery, women received a higher V-T than men during intra-operative ventilation. The risk for a female not to receive LTVV during surgery was double that of males. Height and ABW were the two mediators of the sex difference in use of LTVV.