Early or Late Parenteral Nutrition in Critically Ill Adults

Abstract

To the Editor: Casaer et al. (Aug. 11 issue)1 provide evidence that early supplemental parenteral nutrition appeared to be inferior to withholding parenteral nutrition until day 8 of the intensive care unit (ICU) stay. However, we think that some limitations of the study should be addressed. Half the patients included were extubated at day 2 and discharged from the ICU at day 4, when they were already receiving two thirds of the caloric demand as oral feeding; this casts doubt on the indication for parenteral nutrition and the correct application of the European Society of Parenteral and Enteral Nutrition guidelines.2 A total of 60% of the study patients underwent cardiac surgery, for which artificial nutritional support is rarely indicated. Initiation of an oral diet after successful extubation is the standard of care. Patients with the strongest indication for nutritional support3 (body-mass index [BMI, the weight in kilograms divided by the square of the height in meters], <17) were excluded from the study. In addition, by neglecting stepwise increases in parenteral nutrition,4 hyperalimentation during stress metabolism with an energy goal up to 32 kcal per kilogram of body weight per day may have been achieved as early as day 3. Concomitant intensive insulin therapy necessarily masked metabolic consequences such as severe hyperglycemia. In our mind, better selection of patients may have indeed shown the benefits of supplemental parenteral nutrition. Thomas W. Felbinger, M.D., Ph.D.