Ultrasonographic estimation of gastric volume in patients after overnight fasting and after ingestion of clear fluids two hours before surgery

Abstract

Pre-operative fasting aims to decrease the volume and increase the pH of gastric contents, hence reducing the risk of aspiration. According to the past literature gastric contents of 25 ml (0.4 ml/kg) and with pH ≤ 2.5 predisposes the patient to pulmonary aspiration hence pre-operative fasting was recommended. Use of two-dimensional ultrasonography is an accurate non-invasive tool to determine gastric volume. We compared the gastric volume using ultrasonography and pH of gastric aspirate by pH strip in patients after overnight fasting and after ingestion of 200 ml clear fluids (water) 2 h prior to surgery.