Prolonged wireless measurement of intragastric pH in foals

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.

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.

Eight healthy foals aged 24-98 days.

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.

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).

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.