Since Mendelson described acid aspiration syndrome, it has been a concern for anesthesiologists everywhere, owing to the associated morbidity and mortality. It has been shown that H2 inhibitors and/or proton pump inhibitors (PPI) may have a beneficial role in high-risk patients.

Francis and Kwik sought to evaluate the impact of ranitidine on gastric pH in patients undergoing elective surgery. The study included 36 patients scheduled for elective surgery - 18 of these received 150 mg ranitidine orally the night prior to and on the morning of surgery. The remaining 18 patients served as controls.

It was noted that:

• In 4 out of the 18 subjects who received ranitidine, no gastric sample could be aspirated.
• The incidence of gastric residue pH greater than 2.5 was found to be significantly higher in patients given ranitidine compared to control patients.
• In 13 of 14 participants receiving ranitidine in whom a gastric juice sample was obtained (93%), pH was greater than 2.5.
• In control subjects, only 7 out of 18 participants (34%) had pH greater than 2.5.
• The high pH was seen for as long as 8.5 hours after the morning dose of ranitidine.

To conclude, higher potency, longer duration of action, and fewer side effects of ranitidine point to the advantages of this drug in regulating gastric pH and having a potential prophylactic role in acid aspiration syndrome.

Sources:

Francis RN, Kwik RS. Oral ranitidine for prophylaxis against Mendelsons syndrome. Anesth Analg. 1982 Feb;61(2):130-2.

Bhattacharyya T, Sarbapalli D, Pal R, et al. Evaluating ranitidine, pantoprazole and placebo on gastric pH in elective surgery. Saudi J Anaesth. 2011 Jan-Mar; 5(1): 67–72.