Gastric feeding intolerance is not caused by mucosal ischemia measured by intragastric air tonometry in the critically ill

Background: Gastric mucosal ischemia may be a risk factor for gastrointestinal intolerance to early feeding in the critically ill. Aims: To study intragastric PCO2 air tonometry and gastric residual volumes (GRV) before and after the start of gastric feeding. Methods: This is a two-center study in intensive care units of a university and teaching hospital. Twenty-nine critically ill, consecutive and consenting patients scheduled to start gastric feeding were studied after insertion of a gastric tonometry catheter and prior to and after start of gastric feeding (500 ml over 1 h), when clinically indicated. Results: Blood gasometry and intragastric tonometry were performed prior to and 2 h after gastric feeding. The intragastric to arterial PCO2 gap (normal <8 mm Hg) was elevated in 41% of patients prior to feeding and measured (mean standard deviation) 13 +/- 20 and 16 +/- 23 mm Hg in patients with normal (<100 ml, 42 +/- 34 ml, n = 19) and elevated GRV (250 +/- 141 ml, n = 10, P = 0.75), respectively. After feeding, the gradient did not increase and measured 27 +/- 25 and 23 +/- 34 mm Hg, respectively (P = 0.80). Conclusion: Gastric mucosal ischemia is not a major risk factor for intolerance to early gastric feeding in the critically ill. (C) 2015 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.