Perioperative pulmonary aspiration and regurgitation without aspiration in adults: a retrospective observational study of 166,491 anesthesia records.

BACKGROUND

Pulmonary aspiration (PA) of gastric contents is a rare but serious perioperative complication. Recent studies focused on pediatric patients, but over a decade has passed since the latest incidence and outcome in adult population have been reported. Patients who experienced regurgitation without aspiration were rarely mentioned. Besides, our department proposed a modified rapid sequence induction (RSI) protocol in 2018 and its preventive effect remained to be examined.

METHODS

A total of 166,491 anesthesia records from March 2015-October 2020 were reviewed. Outcomes from regurgitation events were classified as PA or regurgitation without aspiration following strict criteria. Available information including demographics, anesthetic managements, surgical procedures, and other medical records were reviewed for analysis.

RESULTS

Among the 166,491 anesthesia records, 20 patients had PA (1:8,325), and 20 had regurgitation without aspiration (1:8,325). The morbidity of PA was 1:16,649, and the mortality was 1:55,497. During anesthesia induction, 76.0% of regurgitation events developed aspiration, and the remaining 24.0% had regurgitation without aspiration. But prior to anesthesia induction, only 10.0% regurgitation events developed aspiration. Emergency procedures were associated with serious risks of PA (OR: 27.1, 95% CI: 10.8-68.0) and regurgitation without aspiration (OR: 83.0, 95% CI: 24.3-283.1) compared with elective procedures. The highest incidence of pulmonary aspiration was observed in bronchoscopy procedures (2/1,747). The modified RSI reduced the incidence of regurgitation events during induction in emergency procedures but did not show significant advantages over classic protocol (0:1,055 versus 12:4,469, P=0.139) possibly due to insufficient sample size. The sample size required for future study was estimated based on the current data.

CONCLUSIONS

The incidence of pulmonary aspiration and regurgitation without aspiration was low, especially in elective cases. Regurgitation during anesthesia induction had mostly developed aspiration. Further evaluation of the effect of modified RSI protocol needs a large sample size.