[Preoperative fasting period of fluids in bariatric surgery]

Aspiration of stomach content is a severe complication during general anaesthesia. The DGAI (German Society for Anesthesiology and Intensive Care Medicine) guidelines recommend a fasting period for liquids of 2 h, with a maximum of 400 ml. Preoperative fasting can affect the patients' recovery after surgery due to insulin resistance and higher protein catabolism as a response to surgical stress.

The aim of the study was to compare a liberal fasting regimen consisting of up to 1000 ml of liquids until 2 h before surgery with the DGAI recommendation.

The prospective observational clinical study was approved by the ethics committee of the University of Leipzig. In the liberal fasting group (G_lib) patients undergoing bariatric surgery were asked to drink 1000 ml of tea up to 2 h before surgery. Patients assigned to the restrictive fasting group (G_res) who were undergoing nonbariatric abdominal surgery were asked to drink no more than 400 ml of water up to 2 h preoperatively. Right after anaesthesia induction and intubation a gastric tube was placed, gastric residual volume was measured and the pH level of gastric fluid was determined. Moreover, the occurrence of aspiration was monitored.

In all, 98 patients with a body mass index (BMI) of G_lib 51.1 kg/m² and G_res 26.5 kg/m² were identified. The preoperative fasting period of liquids was significantly different (G_lib 170 min vs. G_res 700 min, p < 0.001). There was no difference regarding the residual gastric volume (G_lib 11 ml, G_res 5 ml, p = 0.355). The pH of gastric fluid was nearly similar (G_lib 4.0; G_res 3.0; p = 0.864). Aspiration did not occur in any patient.

There is evidence suggesting that a liberal fluid fasting regimen (1000 ml of fluid) in the preoperative period is safe in patients undergoing bariatric surgery.