Intragastric pH in critically ill neonatal foals and the effect of ranitidine.
OBJECTIVE
To characterize intragastric pH profiles in critically ill foals and determine whether administration of ranitidine altered pH profiles.


METHODS
Prospective observational study.


METHODS
23 hospitalized neonatal foals < or = 4 days of age.


METHODS
Intragastric pH was measured continuously for up to 24 hours by use of an indwelling electrode and continuous data recording system. In 21 foals, ranitidine was administered IV.


RESULTS
10 foals had predominantly or exclusively alkaline profiles, 10 had profiles typical of those reported for healthy foals, with periods of acidity (hourly mean pH < 5.0 at least once), and 3 had atypical profiles with periods of acidity. All 10 foals that had intragastric pH profiles typical of healthy foals survived, whereas only 2 foals with alkaline profiles survived, and none of the foals with atypical profiles survived. The effects of ranitidine administration could not be assessed in 13 foals because of a high baseline intragastric pH. In 7 of the remaining 9, ranitidine administration resulted in an alkalinizing response, but this response was often of blunted duration. Ranitidine administration did not appear to alter the intragastric pH profile in the remaining 2 foals.


CONCLUSIONS
Results suggested that hospitalized critically ill foals often have intragastric pH profiles different from those reported for healthy foals and may respond differently to ranitidine administration than do healthy foals. Many critically ill foals have continuously alkaline intragastric pH profiles, questioning the need for prophylactic administration of ranitidine in all critically ill foals.
Sanchez
L C
LC
Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville 32610, USA.
Lester
G D
GD
Merritt
A M
AM
D000818:Animals; D000831:Animals, Newborn; D000897:Anti-Ulcer Agents / Q000008:administration & dosage / Q000494:pharmacology*; D016638:Critical Illness / Q000628:therapy; D005260:Female; D005440:Fluid Therapy / Q000662:veterinary; D005745:Gastric Acidity Determination / Q000662:veterinary; D005753:Gastric Mucosa / Q000378:metabolism; D006734:Horse Diseases / Q000188:drug therapy*; D006736:Horses; D006863:Hydrogen-Ion Concentration; D008297:Male; D011446:Prospective Studies; D011899:Ranitidine / Q000008:administration & dosage / Q000494:pharmacology*; D013270:Stomach / Q000187:drug effects*; D013997:Time Factors
D000897:Anti-Ulcer Agents; D011899:Ranitidine