In an online article of The New England Journal of Medicine, Casaer et al present data from a prospective, randomized, controlled, parallel-group, multicenter trial conducted in Belgium. The Early Parenteral Nutrition Completing Enteral Nutrition in Adult Critically Ill Patients (EPaNIC) investigators sought to assess outcomes between patients treated with parenteral nutrition (PN) within 2 days after intensive care unit (ICU) admission (early PN group; European guidelines / control group) versus 8 days after admission (late PN group; North American guidelines / active intervention group). Investigators were blinded to the block randomization process, but not to the actual intervention. Patients had similar baseline characteristics, including a mean Acute Physiology and Chronic Health Evaluation (APACHE) II score of 23, with the exception of slightly increased, but statistically significant, overall body weight in the early PN group. Patients in both groups received enteral nutrition by the second day in the ICU unless medically contraindicated and both groups were managed with tight glycemic control (80-110 mg/dL).

A total of 4,640 patients underwent randomization: 2,328 in the late PN group, and 2,312 in the early PN group. Total energy levels were not statistically different between groups by day 15 of the study. Both groups had similar rates of ICU and hospital mortality at 90 days. Patients in the late PN group had a median ICU length of stay that was 1 day shorter (hazard ratio, 1.06; 95% confidence interval, 1.00 to 1.13; P=0.04), and a median hospital length of stay that was 2 days shorter. The late PN group also had fewer infections, shorter duration of mechanical ventilation and shorter duration for renal-replacement therapy. Healthcare costs were decreased for the late PN group by approximately $1,600 USD per patient. The late PN group had higher levels of inflammation, as assessed by C-reactive protein levels.

Previous observational trials demonstrated improved outcomes for critically ill patients who reached nutritional targets earlier with PN. In this study, early initiation of PN was not beneficial when compared to late initiation. Although the effects of other co-interventions (such as immunonutrition) were not studied, all primary and secondary endpoints indicated that early PN was not beneficial, and that adherence to North American PN guidelines, which advocate late PN initiation in ICU patients, is likely more judicious.

Concise Critical Appraisal is a regular feature authored by SCCM member Samuel M. Galvagno Jr., DO. Each installment highlights journal articles most relevant to the critical care practitioner.