Ultrasound Assessment of Metoclopramide Effect on Gastric Volume in Patients Undergoing Cesarean Section: A Randomized, Double-blind, Cross-sectional Study"

Since regional anesthesia has largely replaced general anesthesia, the risk of aspiration pneumonitis during cesarean sections has significantly decreased. Nevertheless, precaution against gastric aspiration is still vital in patients in whom regional anesthesia contraindicated or in whom general anesthesia has to be administered (for example; during emergency cesarean delivery). The administration of intravenous anesthetics reduces the level of consciousness of a patient that compromises the protective reflexes of the upper airways. Moreover, a high level of sedation also reduces the tone of the LES (lower oesophageal sphincter). Both these situations predispose the risk of aspiration pneumonia in patients awaiting surgical interventions in supine position under general anesthesia .

The risk of aspiration increases in outpatients if the volume of the gastric contents increases beyond 25 ml, and its pH falls below 2.5. However, the risk of aspiration significantly decreases in "fasted" outpatients. Since most patients awaiting elective surgery remains fasted, routine prophylaxis for preventing aspiration pneumonitis not recommended anymore. Studies suggest that metoclopramide, in combination with H2-receptor antagonists (such as cimetidine), significantly reduces the risk of postoperative emesis and aspiration pneumonitis. However, the time available for administering oral prophylaxis with such anti-emetic and anti-histaminic is too short for these medications to be effective