title: Evaluation of a wireless ambulatory capsule (SmartPill®) to measure gastrointestinal tract pH, luminal pressure and temperature, and transit time in ponies.
abstract: BACKGROUND
  This study investigated the use of a wireless ambulatory capsule (WAC; SmartPill(®) pH.p GI Monitoring System) to determine WAC-gastric emptying time (GET) in ponies.
  
  
  OBJECTIVE
  To measure WAC-GET and compare it to those findings with GET assessed by nuclear scintigraphy (S-GET).
  
  
  OBJECTIVE
  WAC-GET will be slower than S-GET, but will be significantly correlated.
  
  
  METHODS
  Seven healthy adult mixed-breed pony mares were used in this study. Feed was withheld for 12 h prior to the WAC administration. After administration, a complete-feed diet was fed to allow the WAC to pass into the stomach. Luminal pH, temperature and pressure were collected by a modified receiver secured to the pony. Once the pH reached a value of ≥ 8.0, it was determined that gastric emptying had occurred, and ponies were fed grass hay. After 5 days, data were downloaded and analysed using proprietary software. During the second period of the study, after at least 2 weeks, 4 of the ponies underwent a standard S-GET test.
  
  
  RESULTS
  The WAC was successfully administered, and data were collected from all ponies. The mean percentage of data packets collected by the receiver was 84.9 ± 3.51% (range 66.8-95.1%). Mean WAC-GET was 7.38 h (range 0.15-46.65 h). Mean gastric pH was 4.75 (range 2.07-6.99). Mean small intestinal transit time was 4.6 h. The mean pH for the small intestine was 8.0. The mean S-GET time (in hours) when 10% of the radioactive feed is present in the stomach (T-90%) was 2.3 h. The S-GET did not correlate significantly with the WAC-GET.
  
  
  CONCLUSIONS
  The WAC was safely administered to ponies, and data were collected using a modified receiver. The WAC-GET varied considerably between ponies, but was ≤ 3 h in 5 of the 6 ponies. The WAC used in this study provided a noninvasive technique that produced novel information about the pony gastrointestinal tract, but owing to the substantial variability in GET values and long transit time it may not be a reliable clinical tool at this time.
authors.affiliation: Department of Veterinary Clinical Sciences, Equine Health Studies Program, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA.
authors.forename: A M
authors.initials: AM
authors.lastname: Stokes
authors.forename: N L
authors.initials: NL
authors.lastname: Lavie
authors.forename: M L
authors.initials: ML
authors.lastname: Keowen
authors.forename: L
authors.initials: L
authors.lastname: Gaschen
authors.forename: F P
authors.initials: FP
authors.lastname: Gaschen
authors.forename: D
authors.initials: D
authors.lastname: Barthel
authors.forename: F M
authors.initials: FM
authors.lastname: Andrews
mesh_terms: D000818:Animals; D001831:Body Temperature; D041981:Gastrointestinal Tract / Q000502:physiology*; D005772:Gastrointestinal Transit / Q000502:physiology*; D006736:Horses / Q000502:physiology*; D006863:Hydrogen-Ion Concentration; D011312:Pressure; D059015:Wireless Technology