Intragastric pH monitoring

Buffering of intragastric pH is an accepted treatment modality for prophylaxis against the development of gastric stress ulcers. This method of prophylaxis is commonly based on the pH value acquired by measurement of gastric aspirate. Recent literature suggests pH measurement techniques that involve gastric aspirate specimens have many flaws. The purpose of this study was to compare gastric pH measurements with the use of a nasogastric sensor, meter system, and pH-sensitive test paper. Fifteen hundred paired serial measurements of intragastric pH were obtained on 19 thermally injured patients (16 men and three women, ages 23 to 79 years, total body surface area burn 25% to 80%). A double-lumen tube containing an antimony/graphite pH sensor incorporated into the tip of the tube was inserted with the use of a standard technique. Each tube was in place an average of 5.7 days (range 1 to 15 days). Patients were randomized into two groups. The first group (six patients) received non-acid-buffering prophylaxis therapy. The second group (13 patients) received standard antacid or antacid/H2 histamine-blocking agent combination prophylaxis therapy. Analysis of the 539 paired measurements for the non-acid-buffering revealed a correlation coefficient of r = 0.532. The 961 measurements from the group receiving gastric acid buffering revealed a correlation coefficient of r = 0.569. Paired t test values for the sample showed a significant difference (18.52, p < 0.0000) between measurement techniques.