Objective: To assess the effects of enteral immunonutrition (IMN) on hospital mortality and length of stay in a heterogeneous group of critically ill patients.
Design: Prospective, randomized, double-blind, controlled clinical trial with an a priori subgroup analysis according to the volume of feed delivered in the first 72 hrs of intensive care unit (ICU) admission.
Setting: A 13-bed adult general ICU in a London teaching hospital.
Patients: A total of 398 patients were enrolled and data from 390 patients (IMN = 193, control = 197) were used for an intention-to-treat analysis. There were 369 patients (IMN = 184, control = 185) who actually received some enteral nutrition, of whom 101 patients (IMN = 50, control = 51) received >2.5 L within 72 hrs of ICU admission. This latter group was defined as the successful "early enteral nutrition" group.
Interventions: Within 48 hrs of ICU admission, patients were randomized to receive either the IMN Impact (Novartis Nutrition), an enteral feed supplemented with arginine, purine nucleotides and omega-3 fatty acids, or an isocaloric, isonitrogenous control enteral feed.
Measurements and results: There was no significant difference in hospital mortality rate between the two groups on an intention-to-treat analysis (Impact group 48%, control group 44%) nor in any other predefined subgroup analysis. However, patients randomized to receive the IMN had higher Acute Physiology and Chronic Health Evaluation II scores (20.1 +/- 7.1 vs. 18.7 +/- 7.1 [p = .07] intention-to-treat [n = 390]; 20.1 +/- 7.2 vs. 18.5 +/- 7.1 [p = .04] received feed [n = 369]). Of the 101 patients achieving early enteral nutrition, those patients fed with the IMN had a significant reduction in their requirement for mechanical ventilation compared with controls (median duration of ventilation 6.0 and 10.5 days, respectively, p = .007) with an associated reduction in the length of hospital stay (medians 15.5 and 20 days, respectively, p = .03).
Conclusion: While the administration of enteral IMN to a general, critically ill population did not affect mortality, those patients in whom it was possible to achieve early enteral nutrition with Impact had a significant reduction in the morbidity of their critical illness.