Background: Early enteral nutrition (EN) is the preferred strategy for feeding the critically ill; however, it is not always possible to initiate EN within the recommended 24 to 48 hours. When these situations arise, controversy exists whether to start feeding early via the parenteral route or to delay feeding until EN can be provided.
Methods: A multicenter, international, observational study examined nutrition practices in intensive care units (ICUs). Eligible patients were critically ill patients with a medical diagnosis who remained in the ICU for >72 hours and received EN >48 hours after admission. Data were collected on site, including patient characteristics, daily nutrition practices, and outcomes at 60 days. Nutrition and clinical outcomes were compared between 3 groups of patients: (1) early parenteral nutrition (PN) (<48 hours after admission) and late EN (>48 hours after admission), (2) late PN and late EN, and (3) late EN and no PN.
Results: Of the 703 patients who met our inclusion criteria, 541 (77.0%) medical patients received late EN and no PN. In patients receiving late EN and PN, 83 (11.8%) received early PN and 79 (11.2%) received late PN. Adequacy of calories and protein from total nutrition was highest in the early PN group (74.1% ± 21.2% and 71.5% ± 24.9%, respectively) and lowest in the late EN group (42.9% ± 21.2% and 38.7% ± 21.6%) (P < .001). The proportion of patients dead or remaining in hospital was significantly higher for early PN compared with late EN and PN (unadjusted hazard ratio for early PN = 0.55; 95% confidence interval, 0.37-0.83, P = .015). However, this difference did not remain significant (P = .65) after adjustment for baseline characteristics.
Conclusions: The results suggest that initiating PN early, when it is not possible to feed enterally early, may improve provision of calories and protein but is not associated with better clinical outcomes compared with late EN or PN.