gastrins and Pneumonia--Aspiration

Eighty women (40 for elective Caesarean section and 40 for elective gynaecological surgery) were randomly assigned to one of five treatment groups and received pre-operatively either no medication; magnesium trisilicate mixture (BP) 30 ml; metoclopramide 10 mg intramuscularly; ranitidine 150 mg orally on the night prior to, and the morning of, surgery; or metoclopramide 10 mg intramuscularly in combination with oral ranitidine 150 mg (the latter again given on the night prior, and the morning, of surgery). The effect of these medications on intragastric pH, volume and serum gastrin-17 was measured. No patient receiving ranitidine had a pH of less than 4. Magnesium trisilicate mixture resulted in the largest intragastric pH change although one woman in this group had a pH of 1.7. The largest intragastric volumes were seen in the patients who had received magnesium trisilicate mixture, whilst the patients who had received metoclopramide in combination with ranitidine had the smallest intragastric volumes. Magnesium trisilicate mixture and metoclopramide resulted in no change in serum gastrin levels. However, in the subjects who had received ranitidine on the night prior to surgery, the fasting serum gastrin was significantly higher (p less than 0.01) than the values in the remaining subjects, the mean (SEM) values being 60.3 (6.3) pg/ml in those not receiving ranitidine and 111.3 (19.5) pg/ml in those who had been given ranitidine.

Topics: Adult; Antacids; Drug Therapy, Combination; Female; Gastrins; Humans; Hydrogen-Ion Concentration; Magnesium; Magnesium Silicates; Metoclopramide; Pneumonia, Aspiration; Pregnancy; Premedication; Ranitidine; Silicic Acid; Silicon Dioxide; Stomach

We previously reported that H2-antagonist medication given for longer than 4 wk may produce complete tolerance to preanesthetic H2 antagonist therapy. In this study, we evaluated the efficacy of preanesthetic proton pump inhibitor (PPI; oral rabeprazol) use in patients receiving regular H2-antagonist (oral famotidine) therapy for more than 4 wk. Forty-eight patients with assumed complete tolerance to H2 antagonists undergoing elective surgery were recruited and randomly assigned to receive either a preanesthetic PPI (rabeprazol 20 mg; n = 24) or H2-antagonist (H2 group; roxatidine 75 mg; n = 24) at 9:00 pm on the day before surgery and 2 h before the induction of anesthesia. Volume of gastric contents and pH values were measured after the induction of anesthesia. Gastric pH value in the PPI group (5.38 +/- 2.42) was significantly higher than in the H2 group (3.27 +/- 1.98; P < 0.01). Gastric volume in the PPI group (8.6 +/- 1.5 mL) was significantly smaller than in the H2 group (15.4 +/- 2.8 mL; P < 0.05; cf. PPI). Fourteen patients in the H2 group were at risk of acid aspiration pneumonia (gastric pH <2.5 or volume >25 mL), whereas only four patients in the PPI group (P < 0.05) were at risk. These data suggest that in patients receiving H2-antagonist therapy for longer than 4 wk, prophylaxis for acid aspiration pneumonia should include preanesthetic PPI medication.. We previously reported that more than 4 wk of administration of H2-antagonists may produce a full tolerance to preanesthetic H2-antagonists. The present study suggests that a proton pump inhibitor may be effective for prophylaxis of acid aspiration pneumonia in patients showing the full tolerance to H2 antagonists.

Topics: 2-Pyridinylmethylsulfinylbenzimidazoles; Adult; Aged; Anti-Ulcer Agents; Benzimidazoles; Drug Tolerance; Famotidine; Female; Gastric Acidity Determination; Gastrins; Histamine H2 Antagonists; Humans; Male; Middle Aged; Omeprazole; Piperidines; Pneumonia, Aspiration; Preanesthetic Medication; Proton Pump Inhibitors; Rabeprazole