How long are mechanically ventilated patients fasted prior to surgery? An exploratory study examining preoperative fasting practices across trauma centres.

For mechanically ventilated patients undergoing surgery, interrupting enteral feeding to prevent pulmonary aspiration is common; however, there are no published preoperative fasting guidelines for these patients, resulting in fasting practices that often vary greatly between hospitals. This retrospective study described fasting practices and surgical outcomes of mechanically ventilated patients across five trauma centres. The primary exposure was hours nil per os before surgery and was stratified into short (<6h) and moderate (≥6h) fasting duration. Shared frailty models assessed the relationship between time to perioperative complication and nil per os category. Three of the five hospitals had preoperative fasting guidelines, and those most compliant required patients to be fed up until surgery. Most patients were fasted ≥6h prior to surgery and no increased risk of complication was found for patients who were fasted <6h. Future studies are needed to establish appropriate preoperative fasting thresholds for mechanically ventilated patients.