Protein Delivery in Intermittent and Continuous Enteral Nutrition in ICU Patients

Acute skeletal muscle wasting in ICU patients is associated with functional impairment and with increased risk of death. Of what we know today, physical disability can persist up to 5 years. Adequate nutrition is the basis for an optimal recovery for ICU patients and for prevention of muscle wasting. Today, continuous feeding is still the standard enteral nutrition form for patients in the ICU to limit the incidence of aspiration. A study of Serpa et al. and Georgia et al. compared the continuous feeding versus a bolus nutrition with a feeding time of 30 - 60 minutes every 4 hours. They showed no statistical differences in complications between both groups. ProBoNo is a prospective, randomized, controlled pilot study of critically ill patients with a protein- rich formula to explore the impact of continuous or intermittent bolus nutrition on muscle breakdown in ICU patients. The investigators would like to recruit 68 patients during the first 24 hours after surgical intensive care unit admission. Prior beginning of nutrition administration, and on the 7th day thereafter the investigators will perform a muscle biopsy and an ultrasound from the vastus lateralis muscle in both groups. The primary outcome is the time from 6.00 am of the following day after admission until the patient reaches his daily protein's target quantity. Secondary outcomes include the diameter and densitiy of the hamstrings assessed by ultrasound and histology, the process of gastric residual volume, number of diarrhoea events and laboratory findings like glucose, urea and insulin like growth factor (IGF)-1, all compared between the two time points. Intermittent feeding is not only more natural and could help to limit the muscle wasting in ICU patients, it is also easier to handle for the ICU caring medical team. A trial from Georgia et al. in 2007 compared continuous to intermittent enteral nutrition. They found that the intermittently fed patients reached their nutrition goal faster than those being continuously nourished. This might in part be explained by feeding interruptions in the continuous feeding regimen. Presumably, preoperative holding of tube feedings in the continuous nutrition group most commonly caused interruptions. Thus, independently from prevention of muscle breakdown, a bolus nutrition would be more attractive.