Prolonged wireless measurement of intragastric pH in foals

Abstract Background The pathogenesis of gastric ulceration is not well understood in foals, and its relationship with gastric acidity requires further investigation. A wireless capsule, designed for intraesophageal pH monitoring in humans, was adapted to measure intragastric pH in adult horses. Hypothesis/Objectives To (1) determine the feasibility of wireless intragastric pH measurement in foals; (2) determine capsule attachment duration; and (3) describe the intragastric pH profiles recorded. Animals Eight healthy foals aged 24-98 days. Methods Prospective interventional study. Capsules were attached to the glandular gastric mucosa under gastroscopic guidance using a hemostasis clip, and pH was recorded continuously. Gastroscopy was performed after 7 days to assess capsule attachment, or after suspected detachment based on sustained pH ≥ 8. Results Capsules remained attached for 7 days (168 hours) in 6 foals (75%). Capsules detached in 2 foals after 5 days (at 121 and 127 hours). The mean of the median pH was 3.0 ± 0.7 and the mean percentage of time the pH was less than 4 (%tpH 4) was 74.0 ± 16.2%. As age increased, median pH significantly decreased (r = −0.75, P = .03) and %tpH 4 significantly increased (r = 0.72, P = .05). No significant correlation was found between age and attachment duration (r = −0.23, P = .58). Conclusions and clinical importance This technique enables minimally invasive, prolonged wireless intragastric pH measurement in foals. The strong negative correlation between age and pH provides additional insight into the gastric physiology of foals.