pH meter, pH paper measure Gastric pH in Tube-Fed Children with Neurologic Impairments and GERD

The study is published in the Journal of Pediatric Gastroenterology and Nutrition.

James Tjon and associates conducted the present study with the objective to determine the extent of agreement between pH paper and handheld pH meter with a laboratory pH meter for gastric pH measurement in children with neurologic impairments and gastrostomy tubes who have gastroesophageal reflux disease (GERD).

In this prospective observational study, gastric contents were aspirated from gastric- or nasogastric-tubes and the pH was measured using 3 techniques: pH paper, handheld pH meter, and laboratory pH meter (the gold standard).

Agreement between techniques was assessed with intra-class correlation coefficient (ICC), Bland-Altman analysis and kappa statistic.

The following results were observed and highlighted-

1. Among 43 patients contributing 67 gastric samples, the ICC was 0.75 (95% CI: 0.69-0.97) between the handheld and laboratory meters, 0.69 (95% CI: 0.63, 0.94) between the pH paper and laboratory meter and 0.69 (95% CI: 0.63 - 0.94) between the handheld meter and paper.
2. The Bland-Altman analysis between the handheld and lab meters showed a mean difference of -0.03 pH units (limits of agreement: -0.52 to 0.47 pH units) and 0.17 pH units (limits of agreement: -0.99 to 1.33 pH units) between the paper and lab meter.
3. The kappa coefficients for a pH ≥ 4 were 1.0 (95% CI: 1.0 to 1.0) between the handheld and lab meters and 0.9 (95% CI: 0.77 to 1.0) between the paper and lab meter.

Hence, the authors concluded that "both point-of-care tests, the pH meter and pH paper, correlate well with the gold standard for testing pH with a laboratory pH meter, indicating usefulness in point-of-care testing for monitoring gastric pH in tube-fed children with neurologic impairments and GERD."