The association of postoperative pulmonary complications in 109,360 patients with pressure-controlled or volume-controlled ventilation

Abstract

We thought that the rate of postoperative pulmonary complications might be higher after pressure-controlled ventilation than after volume-controlled ventilation. We analysed peri-operative data recorded for 109,360 adults, whose lungs were mechanically ventilated during surgery at three hospitals in Massachusetts, USA. We used multivariable regression and propensity score matching. Postoperative pulmonary complications were more common after pressure-controlled ventilation, odds ratio (95%CI) 1.29 (1.21-1.37), p < 0.001. Tidal volumes and driving pressures were more varied with pressure-controlled ventilation compared with volume-controlled ventilation: mean (SD) variance from the median 1.61 (1.36) ml.kg^-1 vs. 1.23 (1.11) ml.kg^-1 , p < 0.001; and 3.91 (3.47) cmH₂ O vs. 3.40 (2.69) cmH₂ O, p < 0.001. The odds ratio (95%CI) of pulmonary complications after pressure-controlled ventilation compared with volume-controlled ventilation at positive end-expiratory pressures < 5 cmH₂ O was 1.40 (1.26-1.55) and 1.20 (1.11-1.31) when ≥ 5 cmH₂ O, both p < 0.001, a relative risk ratio of 1.17 (1.03-1.33), p = 0.023. The odds ratio (95%CI) of pulmonary complications after pressure-controlled ventilation compared with volume-controlled ventilation at driving pressures of < 19 cmH₂ O was 1.37 (1.27-1.48), p < 0.001, and 1.16 (1.04-1.30) when ≥ 19 cmH₂ O, p = 0.011, a relative risk ratio of 1.18 (1.07-1.30), p = 0.016. Our data support volume-controlled ventilation during surgery, particularly for patients more likely to suffer postoperative pulmonary complications.

Keywords: lung protection ventilation: pressure goal; pressure-controlled ventilation; volume-controlled ventilation.

Figure 1

Flow of patients through study. ASA, ASA physical status; BMI, body mass index, CCI, Charlson Comorbidity Index; F_IO₂, inspired oxygen fraction; PEEP, positive end-expiratory pressure; PCV, pressure-controlled ventilation; RVU, relative value units; VCV, volume-controlled ventilation.

Figure 2

(a) The tidal volumes and (b) the driving pressures delivered by pressure-controlled ventilation () and volume-controlled ventilation () during surgery in 18,268 patients and 91,092 patients, respectively.