A Double-Blind Randomized Clinical Trial Comparing the Effect of Neostigmine and Metoclopramide on Gastric Residual Volume of Mechanically Ventilated ICU Patients

BACKGROUND In critically ill patients, enteral feeding through the nasogastric tube is the method of choice for nutritional support. Gastrointestinal feeding intolerance and disturbed gastric emptying are common challenges in these patients. The aim of this study was to compare the effect of Neostigmine and Metoclopramide on gastric residual volume (GRV) in mechanically ventilated ICU patients. METHODS In a double blind, randomized clinical trial, a total of 60 mechanically ventilated ICU patients with GRV >120 mL (3 hours after the last gavage), were randomly assigned into two groups A and B. At baseline and 6 hours later, patients in group A and B received intravenous infusion of neostigmine in a dose of 2.5 mg and metoclopramide in a dose of 10 mg in 100 ml of normal saline, within 30 minutes. Patients' gastric residual volumes were evaluated before the beginning of the intervention, and 3, 6, 9 and 12 hours after the intervention. RESULTS After adjusting of other variables (Sex, BMI and ICU stay period) generalized estimating equation (GEE) model revealed that neostigmine treatment increased odds of GRV improvement compare to metoclopramide group (Estimate 1.291, OR= 0.3.64, 95% CI 1.07-12.34). However there is a statistically significant time trend (within-subject differences or time effect) regardless of treatment groups (P<0.001). The median time from intervention to GRV improvement was 6 hours (95% CI 3.75-8.25) and 9 hours (95% CI 7.38-10.17) in neostigmine and metoclopramide groups, respectively. This difference was statistically significant (P<0.05). CONCLUSION It seems that neostigmine is more effective than metoclopramide in reducing GRV and improving gastric emptying in mechanically ventilated ICU patients without significant complication and this protocol may be effective on the tolerance of enteral feeding in ICU patients. Further well-designed randomized clinical trials are needed.