Gastrointestinal failure during critical illness is associated with decreased intake and limited tolerance to enteral feeding. Enterohormones like ghrelin and PYY could play a role in these dysfunctions. This study aimed at defining:

– the time course of serum ghrelin and PYY during the first 5 days of stay;

– correlations with limited tolerance to enteral feeding.

Thirty consecutive patients (age: 56.4±16.4; BMI: 26.3±4.5) and 10 fasting healthy volunteers (age: 34.1±6.8; BMI: 23.1±4.2) were included. In patients, blood was sampled for 5 consecutive days and once in the control group. Blood samples were immediately centrifuged at 3000×g for 10minutes at 4°C. Ghrelin samples were acidified to pH 4 and then all samples were stored at –80°C until processing. Ghrelin and PYY serum concentrations were measured using a commercial ELISA test. Enteral feeding intolerant patients were defined as patients with at least one episode of high gastric residual volume (>250mL) and/or diarrhea (>200mL of liquid stools/day). Comparisons between continuous variables were done using ANOVA and the Wilcoxon U-test as appropriated. Alpha error was set at 5%.

The incidence of intolerance among patients was 41.4%. Mean gastric residual volume (millilitres) was higher in intolerant than in tolerant patients (P<0.05 for each day). Intolerant patients had a higher PYY serum concentration than tolerant patients (median (IQR): 53.5pg/mL [17.5–191.7pg/mL] vs. 17.7pg/mL [4.8–62.5pg/ml]; P=0.03) and than controls (53.5pg/mL [17.5–191.7pg/mL] vs. 6.4pg/mL [0.35–18.1pg/mL]; P=0.02). Daily PYY serum concentration was higher in intolerant than in tolerant patients, specifically on days 2 (median (IQR): 103.2pg/mL [23.2–193.6pg/mL] vs. 16.9pg/mL [3.9–54pg/mL]; P=0.02) and day 5 (103.2pg/mL [23.2–193.6pg/mL] vs. 16.9pg/mL [3.9 to 54pg/mL]; P=0.02). Controls had a significantly higher serum ghrelin concentration than either tolerant patients (median (IQR): 1435.7pg/mL [1335.5–1775.5pg/mL] vs. 219.4pg/mL [84–420.5pg/mL]; P<0.0001) or intolerant patients (1435.7pg/mL [1335.5–1775.5pg/mL] vs. 283.5pg/mL [92–1002.5pg/mL]; P=0.004). Unexpectedly, serum ghrelin concentration was higher in intolerant compared to tolerant patients (median (IQR): 283.5pg/mL [92–1002.5pg/mL] vs. 219.4pg/mL [84–420.5pg/mL]; P=0.02). No difference in serum ghrelin concentration between tolerant compared to intolerant patients was found from day 1 to day 5.

In critically ill patients, mean serum concentration of ghrelin and PYY significantly differ from that of healthy controls. These findings support a role of enterohormones in the critical illness-associated gastrointestinal failure.