The optimal time to initiate parenteral nutrition in critically ill patients unable to get adequate enteral nutrition is a subject of ongoing debate. European guidelines recommend parenteral nutrition in these patients within 24-48 hours of ICU admission ( Clin Nutr 2009 Aug;28(4):387), while American-Canadian guidelines recommend waiting for at least 7 days (JPEN J Parenter Enteral Nutr 2009 May-Jun;33(3):277). The 2 strategies were compared in a new unblinded trial. A total of 4,640 intensive care patients were randomized to parenteral nutrition initiated early (48 hours after ICU admission) vs. late (on day 8 after admission). All patients were classified as being at nutritional risk (risk score of ? 3 on 7-point scale), as determined by assessment of disease severity, age, extent of weight loss within previous 3 months, and extent of food intake within previous week. Underlying conditions included sepsis in 22%, cancer in 19%, and diabetes in 17%.
Comparing early vs. late initiation of parenteral nutrition, the median ICU stay was 4 days vs. 3 days (p = 0.02), and the median hospital stay was 16 days vs. 14 days (p = 0.004) (level 2 [mid-level] evidence). New infections occurred in 26% vs. 23% (p = 0.008, NNH 25), and mechanical ventilation was required for > 2 days in 40% vs. 36% (p = 0.006, NNH 25). Early initiation was also associated with increased duration of renal replacement therapy (10 days vs. 7 days, p = 0.008). There were no significant differences in mortality during ICU or hospital stays or at 90 days (N Engl J Med 2011 Aug 11;365(6):506).
For more information, see the Parenteral nutrition support in adults topic in DynaMed.