Research Finds No Evidence Supporting Fasting Before Surgery to Prevent Postoperative Vomiting

A comprehensive review of existing data reveals that fasting prior to surgery does not effectively prevent post-surgical vomiting or aspiration pneumonia. Traditionally, patients are required to fast for hours before anesthesia because of concerns about aspiration—the entry of gastric contents into the lungs—which can lead to serious complications. However, recent analysis of randomized clinical trials and observational studies published between 2016 and 2023 demonstrates that fasting duration is not associated with a decreased risk of aspiration or vomiting.

The review included data from 17 studies involving over 1,800 patients, comparing fasting protocols with real-world fasting times across diverse healthcare settings. The primary focus was on clinical aspiration, with secondary measures including gastric volume and pH levels. The findings show that aspiration incidents are very rare, occurring in about 0.5% of patients in both fasting and non-fasting groups, with no significant difference observed.

Further analysis indicated that most studies used gastric volume and pH as surrogate markers for aspiration risk, but these parameters have not been conclusively linked to actual aspiration events during anesthesia. Additionally, researchers examined the discrepancy between recommended fasting durations and actual fasting times, discovering that many patients fast excessively long periods—resulting in unnecessary discomfort and inconvenience.

Moving forward, the authors suggest that reducing preoperative fasting times could improve patient comfort. Prospective trials utilizing modern risk assessment tools, such as gastric ultrasound, are planned to evaluate safety under shorter fasting protocols. Dr. Edward Livingston from UCLA emphasizes that long fasting periods are unpleasant for patients and that current evidence suggests such practices may be unnecessary.

This study underscores the need to revisit and potentially revise fasting guidelines to enhance patient experience without compromising safety, based on current evidence showing no link between fasting and aspiration prevention.

Source: https://medicalxpress.com/news/2025-06-evidence-patients-fast-prior-surgery.html