Use of a concentrated enteral nutrition solution to increase calorie delivery to critically ill patients: a randomized, double-blind, clinical trial.

Multicenter, randomized, double-blind trial in 5 Australian tertiary-referral ICUs. The study enrolled mechanically ventilated adults expected to require enteral nutrition for at least 2 days; 57 participants were randomized to the 1.5 kcal/mL formula and 55 to the 1.0 kcal/mL formula.

Critically ill adults received a concentrated enteral nutrition formula at 1.5 kcal/mL, delivered enterally at 1 mL/kg ideal body weight per hour, with a maximum rate of 100 mL/h. The comparator was a standard 1.0 kcal/mL enteral nutrition formula given at the same rate for up to 10 days or until ICU discharge.

The concentrated 1.5 kcal/mL formula increased calorie delivery without increasing enteral intolerance. Daily calorie delivery was 1832 kcal/d versus 1259 kcal/d with the 1.0 kcal/mL formula (P < 0.001), and 89% versus 16% of study feeding days met estimated caloric requirements. Daily volume delivered was similar (1221 mL/d versus 1259 mL/d; P = 0.628), showing the benefit came from higher energy density rather than higher volume. Ninety-day mortality was 20% versus 37% (P = 0.057), but ICU, hospital, and 28-day mortality did not differ, and the trial was not powered to test mortality effects.

The sample size was small and the study was not powered for mortality or other clinical outcomes. Intervention exposure was limited to up to 10 days in mechanically ventilated ICU patients from Australian tertiary centers, which limits generalizability. The borderline 90-day mortality signal should be interpreted cautiously because it was not statistically significant.