Assessing nutritional status in chronically critically ill adult patients

Numerous methods are used to measure and assess nutritional status of chronically critically ill patients.

To discuss the multiple methods used to assess nutritional status in chronically critically ill patients, describe the nutritional status of chronically critically ill patients, and assess the relationship between nutritional indicators and outcomes of mechanical ventilation.

A descriptive, longitudinal design was used to collect weekly data on 360 adult patients who required more than 72 hours of mechanical ventilation and had a hospital stay of 7 days or more. Data on body mass index and biochemical markers of nutritional status were collected. Patients' nutritional intake compared with physicians' orders, dieticians' recommendations, and indirect calorimetry and physicians' orders compared with dieticians' recommendations were used to assess nutritional status. Relationships between nutritional indicators and variables of mechanical ventilation were determined.

Inconsistencies among nurses' implementation, physicians' orders, and dieticians' recommendations resulted in wide variations in patients' calculated nutritional adequacy. Patients received a mean of 83% of the energy intake ordered by their physicians (SD 33%, range 0%-200%). Patients who required partial or total ventilator support upon discharge had a lower body mass index at admission than did patients with spontaneous respirations (Mann-Whitney U = 8441, P = .001).

In this sample, the variability in weaning progression and outcomes most likely reflects illness severity and complexity rather than nutritional status or nutritional therapies. Further studies are needed to determine the best methods to define nutritional adequacy and to evaluate nutritional status.