Frequency of under- and overfeeding in mechanically ventilated ICU patients: causes and possible consequences

Introduction In critically ill patients enteral nutrition (EN) is frequently associated with underfeeding and intolerance, whilst parenteral nutrition (PN) has been associated with a greater risk of infectious complications and overfeeding. Materials and methods The adequacy of nutritional support provided to critically ill patients was prospectively recorded and compared with estimated requirements. The incidence of, and practices contributing to, under- (< 80% of energy requirements) and overfeeding (> 110% of energy requirements) were identified. Results Overall patients received approximately 81% and 76% of prescribed energy and protein intakes respectively. Underfeeding occurred on 50.3% of days. Reasons for patients failing to achieve adequate intakes included, fasting for airway management procedures (21%) and gastrointestinal intolerance (14%). Overfeeding, although less common (18.6% of days), was more likely to occur in patients with a tracheostomy requiring prolonged mechanical ventilation (> 16 days). The combination of oral and nasogastric feeding or use of nutrient-dense feeds were most frequently associated with overfeeding. Discussion The overall adequacy of nutritional intakes in the present study was similar to those reported elsewhere. However, the incidence of overfeeding was greater than anticipated and occurred in patients already experiencing delayed weaning from mechanical ventilation.