A prospective survey of nutritional support practices in intensive care unit patients: What is prescribed? What is delivered?

Objectives: To assess the amount of nutrients delivered, prescribed, and re quired for critically ill patients and to identify the reasons for discrepa ncies between prescriptions and requirements and between prescriptions and actual delivery of nutrition. Design: Prospective cohort study. Setting: Twelve-bed medical intensive care unit in a university-affiliated general hospital. Patients: Fifty-one consecutive patients, receiving nutritional support eit her enterally or intravenously for greater than or equal to 2 days. We foll owed patients for the first 14 days of nutritional delivery. Measurements and Main Results: The amount of calories prescribed and the am ount actually delivered were recorded daily and compared with the theoretic al energy requirements. A combined regimen of enteral and parenteral nutrit ion was administered on 58% of the 484 nutrition days analyzed, and 63.5% o f total caloric intake was delivered enterally. Seventy-eight percent of th e mean caloric amount required was prescribed, and 71% was effectively deli vered, The amount of calories actually delivered compared with the amount p rescribed was significantly lower in enteral than in parenteral administrat ion (86.8% vs. 112.4%, p < .001). Discrepancies between prescription and de livery of enterally administered nutrients were attributable to interruptio ns caused by digestive intolerance (27.7%, mean daily wasted volume 641 mL) , airway management (30.8%, wasted volume 745 mL), and diagnostic procedure s (26.6%, wasted volume 567 mL). Factors significantly associated with a lo w prescription rate of nutritional support were the administration of vasoa ctive drugs, central venous catheterization, and the need for extrarenal re placement. Conclusions: An inadequate delivery of enteral nutrition and a low rate of nutrition prescription resulted in low caloric intake in our intensive care unit patients. A large volume of enterally administered nutrients was wast ed because of inadequate timing in stopping and restarting enteral feeding. The inverse correlation between the prescription rate of nutrition and the intensity of care required suggests that physicians need to pay more atten tion to providing appropriate nutritional support for the most severely ill patients.