Prolonged wireless measurement of intragastric pH in foals.

Overview

• This study investigated the feasibility of using a wireless capsule to measure stomach acidity (intragastric pH) continuously in foals over several days.
• The researchers successfully monitored gastric pH in foals and found that stomach acidity changes with age, providing new insights into foal gastric physiology.

Background and Rationale

• Gastric ulceration is a common but poorly understood problem in foals, and the role of stomach acidity in its development needs further study.
• A wireless pH monitoring capsule originally designed for humans was previously adapted for adult horses, showing promise for non-invasive gastric studies.
• This technology had not yet been tested in foals, and understanding gastric acidity patterns in this age group could help clarify ulcer pathogenesis.

Objectives

• Determine if it is feasible to wirelessly measure intragastric pH continuously in foals using the adapted capsule technology.
• Assess how long the capsule remains attached to the stomach lining during prolonged monitoring.
• Describe the gastric pH profiles recorded over time in healthy foals to understand acidity patterns.

Methods

• Subjects: Eight healthy foals aged between 24 and 98 days were included.
• Study Design: Prospective interventional study with wireless pH capsule placement.
• Procedure:
  • Capsules were endoscopically attached to the glandular mucosa of the foals’ stomachs using a hemostasis clip.
  • Continuous pH data was recorded wirelessly after placement.
  • Follow-up gastroscopy was performed after 7 days or earlier if capsule detachment was suspected (indicated by pH readings ≥8 sustained over time).

Results

• Capsule Retention:
  • In 6 out of 8 foals (75%), the wireless capsule remained attached for the full 7 days (168 hours).
  • In 2 foals, capsules detached earlier, at 121 and 127 hours respectively (about 5 days).
• Gastric pH Measurements:
  • The overall average median intragastric pH was 3.0 ± 0.7, indicating generally acidic stomach environments.
  • On average, the foals’ stomach pH was below 4 for 74.0 ± 16.2% of the total recorded time, suggesting that the stomach remained relatively acidic most of the time.
• Correlation with Age:
  • A significant negative correlation was found between age and median pH (r = -0.75, P = .03), meaning stomach acidity increased (lower pH) as foals grew older.
  • The percentage of time pH was below 4 increased significantly with age (r = 0.72, P = .05), reinforcing the trend toward more acidic gastric environments in older foals.
  • No significant correlation was found between the duration capsules remained attached and the age of foals (r = -0.23, P = .58), suggesting capsule retention time was not age-dependent.

Conclusions and Significance

• The study demonstrated that minimally invasive, prolonged wireless measurement of intragastric pH is feasible and effective in foals.
• The wireless capsule technology reliably recorded pH for up to 7 days in most foals, enabling detailed assessment of gastric acidity over time.
• The observed negative correlation between age and gastric pH provides important new information about how gastric acidity develops in young horses, which may have implications for understanding the risk and pathogenesis of gastric ulcers in foals.
• These findings open avenues for future research on ulcer prevention and treatment by monitoring gastric acidity dynamically in clinical and research settings.