A narrative review surveys recent changes in approaches to preoperative fasting. It particularly focuses on clear fluids and the evidence from clinical as well as gastric ultrasound studies, endorsing 2 hour fasting for clear fluids, and the more recent adoption of 1 hour clear fluid fasting in Pediatrics. Clinical scheduling and logistic issues have however still led to unnecesssry prolonged fasting.
The topic of carbohydrate loading is also discussed, usually as 50g maltodextrin polysaccharide in 400 ml – twice the evening before surgery and within 2 – 4 hours of surgery. While Insulin resistance is diminished and small improvements in enhanced recovery have been reported, further evidence on outcome is needed, as well as the risk/benefit in diabetic patients.
Other risk analysis (with possible gastric ultrasound support) may be needed in those with reflux, GI obstruction, esophageal disease or pregnancy, among other individual cases.