Geo–economic variations in epidemiology, ventilation management and outcome of patients receiving intraoperative ventilation during general anesthesia– posthoc analysis of an observational study in 29 countries

Background: The aim of this analysis is to determine geo–economic variations in epidemiology, ventilator settings and outcome in patients receiving general anesthesia for surgery. Methods: Posthoc analysis of a worldwide study in 29 countries. Lower and upper middle–income countries (LMIC and UMIC), and high–income countries (HIC) were compared. The coprimary endpoint was the risk for and incidence of postoperative pulmonary complications (PPC); secondary endpoints were intraoperative ventilator settings, intraoperative complications, hospital stay and mortality. Results: Of 9864 patients, 4% originated from LMIC, 11% from UMIC and 85% from HIC. The ARISCAT score was 17.5 [15.0–26.0] in LMIC, 16.0 [3.0–27.0] in UMIC and 15.0 [3.0–26.0] in HIC (P =.003). The incidence of PPC was 9.0% in LMIC, 3.2% in UMIC and 2.5% in HIC (P <.001). Median tidal volume in ml kg^{− 1} predicted bodyweight (PBW) was 8.6 [7.7–9.7] in LMIC, 8.4 [7.6–9.5] in UMIC and 8.1 [7.2–9.1] in HIC (P <.001). Median positive end–expiratory pressure in cmH₂O was 3.3 [2.0–5.0]) in LMIC, 4.0 [3.0–5.0] in UMIC and 5.0 [3.0–5.0] in HIC (P <.001). Median driving pressure in cmH₂O was 14.0 [11.5–18.0] in LMIC, 13.5 [11.0–16.0] in UMIC and 12.0 [10.0–15.0] in HIC (P <.001). Median fraction of inspired oxygen in % was 75 [50–80] in LMIC, 50 [50–63] in UMIC and 53 [45–70] in HIC (P <.001). Intraoperative complications occurred in 25.9% in LMIC, in 18.7% in UMIC and in 37.1% in HIC (P <.001). Hospital mortality was 0.0% in LMIC, 1.3% in UMIC and 0.6% in HIC (P =.009). Conclusion: The risk for and incidence of PPC is higher in LMIC than in UMIC and HIC. Ventilation management could be improved in LMIC and UMIC. Trial registration: Clinicaltrials.gov, identifier: NCT01601223.