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