Acid aspiration into the lungs is a potential complication of general anesthesia. Pharmacological agents are often used to reduce gastric volume and increase gastric pH.

A meta-analysis of randomized controlled trials sought to compare the net benefit of proton pump inhibitors (PPIs) with histamine 2 blockers in reducing gastric fluid volume and increasing gastric pH. Investigators searched electronic databases for trials that compared ranitidine with PPIs in their effect on volume and pH of gastric fluid aspirates.

Nine trials were identified, of which seven were found to be suitable for meta-analysis. Pooled outcomes suggested that premedication with ranitidine was more effective than PPIs in reducing the volume of gastric secretions by an average of 0.22 ml/kg. Ranitidine was more effective in increasing gastric pH as well, by an average of 0.85 pH units.

Use of ranitidine is associated with better outcomes for gastric fluid volume and pH, in comparison with PPIs.

Source: Clark K, Lam LT, Gibson S, Currow D. The effect of ranitidine versus proton pump inhibitors on gastric secretions: a meta-analysis of randomised control trials. Anaesthesia. 2009 Jun;64(6):652-7.