Intraoperative ventilation settings in Germany: an observational multicentre cross-sectional study

Intraoperative lung protective ventilation and, in inhalational anesthesia, minimal fresh gas flow (FGF) are recommended. It remains unclear how these recommendations are transferred to clinical routine. We aimed to assess corresponding anesthesia practices in Germany and raise awareness of optimal ventilation settings.

We performed a pragmatic prospective observational national cross-sectional assessment of intraoperative ventilation settings in Germany, followed by an educational intervention and follow-up assessment. The intervention consisted of a pocket card designed in a Delphi-process. The patient-centred primary endpoint was tidal volume (V_T)·kg^-1 ideal body weight (IBW), and the environment-centred primary endpoint was FGF in inhalational anesthesia. In a post hoc analysis, we grouped departments into quintiles of baseline V_T and FGF, and explored changes after the intervention.

Over 240 of 1,148 anesthesiology departments participated (21%). We collected data from 2,198 operating rooms in the first (preintervention) and 2,106 in the second (postintervention) assessment (96% response rate). The mean (standard deviation) V_T·kg^-1 IBW was 7.4 (1.4) mL in the first assessment vs 7.3 (1.3) mL in the second assessment. The median [interquartile range (IQR)] FGFs were 0.60 [0.50-0.85] L·min^-1 vs 0.50 [0.45-0.75] L·min^-1, respectively. Exploratory multilevel regression analysis did not show an effect of the intervention. In the anesthesiology departments whose baseline ventilation settings were in the highest quintile, the intervention was associated with improvements in both V_T and FGF.

This large-scale clinical study of intraoperative ventilation settings in Germany found that most anesthesiologists already followed current recommendations. Therefore, for the entire cohort, no major improvements were observed. The educational intervention might improve ventilation settings in anesthesiology departments whose baseline practice deviates strongly from current recommendations.