Letter to the Editor: In Response
From our studies, the most effective drug was ranitidine 50 mg intravenously (IV) as it successfully eliminated the risk of acid pneumonitis and provided at least 30 min between administration and endotracheal intubation. Omeprazole 40 mg IV was marginally less successful, although equally effective, if allowed another 10 min or so. It is possible that a larger dose of omeprazole would have a more rapid onset. Unfortunately, cost is a consideration, particularly in the context of the number of patients potentially requiring prophylaxis. Because of the extensive investigation establishing the safety of ranitidine to the neonate, our current recommendation would be to use ranitidine 50 mg IV if an H2 receptor antagonist prophylaxis is used.
In our own institution, we use neither regimen routinely. The number of patients receiving general anesthesia for urgent cesarean section is approximately 3000/yr (about 60% of the total), and the argument for an increase in our pharmaceutical budget would need to be extremely strong. At present we feel that the issue is not resolved as there may be more simple, effective methods of risk reduction that have yet to be investigated. Currently we and other units are increasing the use of regional anesthesia for urgent cesarean section. If 30 min is available for the onset of ranitidine, then spinal anesthesia is certainly a reasonable alternative. One argument for using aspiration prophylaxis is the cost comparison of intensive care management of the occasional case of acid pneumonitis. However, while cases of aspiration under general anesthesia have occurred, only obstetric patients who aspirated during convulsions prior to admission required intensive care for aspiration pneumotitis over the last 6 yr in our unit.
We do not use intravenous metoclopramide routinely as we are unconvinced of its ability to reduce gastric volume in the time available, particularly as many of our patients have received opiates. Like other centers, we have observed occasional episodes of hypotension, supraventricular tachycardia, and extrapyramidal symptoms with its use. The main advantage would be its action upon lower esophageal sphincter tone, but we feel that adequately placed cricoid pressure is more appropriate. We, therefore, rely upon routine use of oral sodium citrate 30 mL (0.3 M) immediately prior to induction and would reserve the use of intravenous ranitidine for patients with a difficult airway where regional anesthesia is contraindicated.
D. A. Rocke, FRCP(Edin), FFA(SA)
C. C. Rout, FFARCS
Department of Anaesthetics, Faculty of Medicine, University of Natal, Congella 4013, South Africa