Gastric motility function in critically ill patients tolerant vs intolerant to gastric nutrition

Background: Administration of gastric enteral nutrition (EN) in the intensive care unit (ICU) is commonly impeded by high gastric residual volumes (GRV). This study evaluated gastric emptying in patients with limited GRV (tolerant group) vs volumes >= 150 mL (intolerant group) and whether prokinetic therapy improves gastric motility in intolerant patients. Methods: To assess gastric motility, mechanically ventilated patients received acetaminophen 975 mg, and peak plasma concentration (Cmax), concentration at 60 minutes (C-60), time to Cmax (Tmax), and area under the concentration-time curve from 0 to 60 minutes (AUC(0-60)) were determined. This evaluation was repeated in, intolerant patients after 24 hours of either erythromycin 250 mg or metoclopramide 10 mg therapy, both administered intravenously every 6 hours. Results: Ten tolerant and 20 intolerant patients were studied. Tolerant patients had significantly greater Cmax (14.12 +/- 7.25 vs 9.28 +/- 5.22 mg/L,; p <.05), C-60 (9.62 +/- 4.65 vs 6.08 +/- 4.00 mg/L; p <.001), and AUC(0-60) (10.01 +/- 5.97 vs 3.93 +/- 2.84 mg/h/L; p <.01) and shortened Tmax (0.81 +/- 0.61 vs 1.98 +/- 1.26 hours; p <.001) compared with intolerant patients. After prokinetic therapy, Cmax (15.26 +/- 8.85 mg/L), C-60 (11.96 +/- 5.99 mg/L), and AUC(0-60) (10.90 +/- 6.57 mg/h/L) increased and Tmax (1.07 +/- 1.01 hours) decreased in the intolerant group to values similar to the tolerant group. Conclusions: ICU patients with elevated GRV during gastric EN have delayed gastric motility. Initiating prokinetic therapy accelerates gastric emptying to resemble that of ICU patients tolerating EN.