Gastrointestinal Hormone Concentrations Associated With Gastric Feeding in Critically Ill Patients

Background: Altered concentrations of ghrelin, motilin, and cholecystokinin (CCK) may contribute to gastric hypomotility. The aims of this study were to evaluate the concentrations of these hormones in patients tolerant and intolerant to gastric nutrition, assess the influence of prokinetic therapy on these hormone concentrations, determine the associations between these mediators and gastric emptying, and evaluate whether inflammation influences their concentrations. Methods: Post hoc analyses of 2 prospective studies that enrolled 20 critically ill patients with an aspirated gastric residual (GR) > 150 mL while receiving gastric enteral nutrition (intolerant group) and 10 critically ill patients with minimal GR (tolerant group). Patients with intolerance were also assessed 1 day after prokinetic therapy. Fasting serum concentrations of total ghrelin, acyl ghrelin (active), des-acyl ghrelin (inactive), motilin, CCK, and tumor necrosis factor (TNF)-alpha were determined. Gastric emptying was assessed concurrently using the acetaminophen absorption method. Results: Compared to the tolerant group, the intolerant group had higher total ghrelin (1324.8 +/- 1204.6 vs 285.1 +/- 132.5 pg/mL; P < .001), lower acyl ghrelin (70.5 +/- 65.4 vs 208.5 +/- 186.9 pg/mL; P < .05), and lower acyl ghrelin to des-acyl ghrelin ratio (1.11 +/- 1.35 vs 3.47 +/- 3.21 pg/mL; P < .05). Concentrations of other hormones and TNF-alpha were similar. Despite accelerated gastric emptying after prokinetic therapy, concentrations of all hormones and TNF-alpha were similar to baseline values. Hormone concentrations were not associated with gastric emptying or TNF-alpha. Conclusion: Patients intolerant to gastric nutrition generate less acyl ghrelin, which may contribute to gastric hypomotility. Intolerance is not associated with altered concentrations of other hormones. Hormone concentrations are not influenced by prokinetic therapy. (JPEN J Parenter Enteral Nutr. 2012;36:189-196)