Abstract: The stomach is rarely completely empty because saliva is swallowed and gastric secretion continues, albeit at low rates, even during periods of fasting. Preoperative fasting guidelines are intended to ensure an empty stomach to minimize the risk of pulmonary aspiration of gastric contents during anaesthesia. Gastric emptying of liquids occurs very rapidly because they can pass immediately through the pylorus, whereas solids must first be digested to semi-fluid chyme. In healthy individuals, 80% of clear liquid empties within 1 h and almost completely within 2 h. Easily digestible solids empty in 3–5 h whereas large particles of indigestible solids may remain in the stomach for much longer. Clinical studies in adults and children demonstrate no difference in volume or pH of residual gastric contents between those patients who have nothing to eat or drink after midnight and those who are allowed to drink clear liquids freely until 2–3 h before induction of anaesthesia. When gastric emptying is delayed for physiological (metabolic, endocrine) or anatomical (pyloric obstruction) reasons, indigestible solids are affected early, followed by digestible solids, whereas clear liquids are affected only at a late stage. Fasting guidelines for healthy, elective patients should not allow solids on the day of surgery, but should allow clear liquids until 3 h before the scheduled, or 2 h before the actual, time of surgery.
Publication Year: 1996
Publication Date: 1996-12-01
Language: en
Type: article
Indexed In: ['crossref']
Access and Citation
AI Researcher Chatbot
Get quick answers to your questions about the article from our AI researcher chatbot