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OR in the News

OR in the News (selected articles)

Turan A, Esa WAS, Rivas E, Wang J, Bakal O, Stamper S, Farag E, Maheswari K, Mao G, Ruetzler K, Sessler DI, Ventilation PTG: Tidal volume and positive end-expiratory pressure and postoperative hypoxemia during general anesthesia: A single-center multiple crossover factorial cluster trial. Anesthesiology 2022; 137: 406-417

July 22, 2022

Background:
Intraoperative mechanical ventilation is a major component of general anesthesia. The extent to which various intraoperative tidal volumes and positive end-expiratory pressures (PEEP) effect on postoperative hypoxia and lung injury remains unclear. We hypothesized that adults having orthope- dic surgery, ventilation using different tidal volumes and PEEP levels affect the oxygenation within first hour in the postoperative care unit.
Methods:
We conducted a two-by-two factorial crossover cluster trial at the Cleveland Clinic Main Campus. We enrolled patients having orthopedic sur- gery with general anesthesia who were assigned to factorial clusters with tidal volumes of 6 or 10 ml/kg of predicted body weight and to PEEP of 5 or 8 cm H 2 O in 1-week clusters. The primary outcome was the effect of tidal volume or PEEP on time-weighted average peripheral oxygen saturation measured by pulse oximetry divided by the fraction of inspired oxygen (Spo2 /Fio2 ratio) during the initial postoperative hour.
Results:
We enrolled 2,860 patients who had general anesthesia for ortho- pedic surgery from September 2018 through October 2020. The interaction between tidal volume and PEEP was not significant (P = 0.565). The mean ± SD time-weighted average of Spo2 /Fio2 ratio was 353 ± 47 and not different in patients assigned to high and low tidal volume (estimated effect, 3.5%; 97.5% CI, –0.4% to 7.3%; P = 0.042), for those assigned to high and low PEEP (estimated effect, –0.2%; 97.5% CI, –4.0% to 3.6%; P = 0.906). We did not find significant difference in ward Spo2 /Fio2 ratio, pulmonary complica- tions, and duration of hospitalization among patients assigned to various tidal volumes and PEEP levels.
Conclusions:
Among adults having major orthopedic surgery, postoperative oxygenation is similar, with tidal volumes between 6 and 10 ml/kg and PEEP between 5 and 8 cm H 2 O. Our results suggest that any combination of tidal volumes between 6 and 10 ml/kg and PEEP between 5 versus 8 ml cm H 2 O can be used safely for orthopedic surgery.