Effect of Age, Feeding, and Omeprazole Administration on Gastric Tonometry in Healthy Neonatal Foals

Abstract

Background: Gastric tonometry is commonly used in humans as an assessment of intestinal mucosal perfusion. Values in healthy foals are currently unknown.Hypothesis: Age, enteral feeding, and omeprazole administration would significantly alter gastric tonometry measurements in neonatal foals.Animals: Nine clinically normal foals were used to assess the effect of age and feeding, and 8 similar foals were used to assess the effect of omeprazole.Methods: At 1, 7, and 14 days of age, gastric intramucosal PCO 2 (PgCO 2 ) and arterial blood gas samples were obtained at baseline, immediately after feeding milk, and 1 and 2 hours after fasting for calculation of the intramucosal-arterial PCO 2 difference (DCO 2 ). To evaluate the effect of omeprazole, foals were evaluated twice as above, 2 hours after fasting, comparing administration of omeprazole to no drug.Results: There was a significant effect of age and feeding on PgCO 2 and DCO 2 , whereas arterial PCO 2 was not significantly affected by these factors. Postfeeding DCO 2 values were significantly lower than fasted values. Baseline and postfeeding DCO 2 increased with age. There was no significant effect of age on data collected after 1 or 2 hours of fasting. The 90% reference interval for DCO 2 data collected after fasting was 0-54 mmHg. Foals had a significantly higher mean gastric pH and significantly higher DCO 2 and PgCO 2 following omeprazole relative to no treatment.Conclusions and Clinical Importance: Because of the high and variable DCO 2 , which is exacerbated by omeprazole administration, the reference interval in foals is extremely wide.

Cardiopulmonary effects of a new inspiratory impedance threshold device in anesthetized hypotensive dogs

“…A second explanation would be that gastric tonometry technology was not sensitive enough to detect changes in GBF. Sanchez et al (2008), when validating gastric tonometry in neonatal foals, commented on the high standard deviation depending on the diet and gastric pH of the animal. All dogs in this study were fed the same diet and were not on any medication that would alter stomach acid production, but gastric pH was not evaluated in the current study.…”

“…The length of the tube was premeasured (tip of the nose to the stomach) and the gastric tonometry tube was placed blindly. Gastric tonometry estimates mucosal perfusion by measuring the amount of CO 2 produced by the gastric mucosa (Cerny & Cvachovec 2000;Sanchez et al 2008). The rationale for this approach is that inadequate oxygen delivery to the stomach results in an increase of lactic acid and gastric CO 2 formation.…”

“…The rationale for this approach is that inadequate oxygen delivery to the stomach results in an increase of lactic acid and gastric CO 2 formation. Increased CO 2 indirectly reflects a decrease in tissue perfusion (Grum et al 1984;Cerny & Cvachovec 2000;Sanchez et al 2008). The gastric-toarterial carbon dioxide gap reflects the mucosal blood supply to metabolic demand balance and is considered a marker of gastric perfusion (Cerny & Cvacho-vec 2000).…”

Prevalence of gastric and duodenal ulceration in 691 nonsurviving foals (1995–2006)

“…2001). Therefore, the pathogenesis of gastric ulcers in this population remains unclear, but may be related to alterations in mucosal perfusion or other mechanisms of mucosal defence (Ryan and Sanchez 2005; Sanchez et al . 2008a).…”

“…However, the intragastric pH in critically ill neonates is more variable and often alkaline (Sanchez et al 2001). Therefore, the pathogenesis of gastric ulcers in this population remains unclear, but may be related to alterations in mucosal perfusion or other mechanisms of mucosal defence Sanchez et al 2008a). Although gastric ulcer prophylaxis is common in many referral hospitals, the prevalence of gastric ulcers in nonsurviving neonates was unaffected by ulcer prophylaxis and in one post mortem study no foals had died as a result of gastric ulceration in one post mortem study (Barr et al 2000).…”