Fish oil supplementation in the parenteral nutrition of critically ill medical patients:: a randomised controlled trial

Objective: To test whether supplementation of parenteral nutrition with fish oil - aimed at increasing the n-3: n-6 ratio of polyunsaturated fatty acids (PUFA) to 1: 2 - affects systemic inflammation and clinical outcome compared to standard parenteral nutrition with an n-3/ n-6 ratio of 1: 7 in medical intensive care unit (ICU) patients. Design: Single-centre, placebo-controlled, double-blind, randomised clinical trial. Setting: Twelve-bed medical ICU of a university hospital. Patients: A total of 166 consecutive patients anticipated to need parenteral nutrition for more than 6 days. Patients were stratified for the presence of systemic inflammatory response syndrome (SIRS) at baseline (115 SIRS, 51 non-SIRS). Intervention: Patients were randomly assigned to receive either a 1: 1-mixture of medium-chain triglycerides (MCT) and long-chain triglycerides (LCT) with an n-3/n-6 PUFA ratio of 1: 7, or the same MCT/LCT emulsion supplemented with fish oil (resulting in an n-3/n-6 ratio of 1: 2). Measurements and results: Primary end-points were changes in interleukin 6 (IL-6) and monocyte HLA-DR expression relative to baseline. Secondary endpoints were incidence of nosocomial infections, duration of mechanical ventilation, length of ICU stay, and 28-day mortality. Bleeding complications were recorded as a possible side effect of fish oil. Between standard and intervention groups, overall as well as stratified for SIRS or non-SIRS, no significant difference was detected in any of the endpoints or frequency and severity of bleeding events. Conclusions: In unselected critically ill medical patients, fish oil supplementation that increased the n-3/n-6 PUFA ratio to 1: 2 did not affect inflammation or clinical outcome, compared to parenteral lipid nutrition with an MCT/LCT emulsion.