Future research and summary
Many questions remain unanswered and present opportunities for future research. Priorities for critical care nutrition research include studying the impact of combined nutrition and exercise in the acute and late phases of critical illness and identifying best tools to differentiate responses to caloric and protein intake.
In summary, critical illness has acute and late phases. The acute phase is a hypercatabolic state leading to negative energy and nitrogen balance and gut dysfunction. Take-home points for nutrition support in the acute phase of critical illness are:
1. It is reasonable to start early hypocaloric EN with an isosmotic formula with slow up-titration over the first week of critical illness while monitoring for refeeding syndrome and feeding intolerance.
2. Use exclusive PN in ICU patients with pre-existing malnutrition when EN is contraindicated or not tolerated.
3. Supplemental PN should probably be restricted during the acute phase of critical illness.
4. Optimal protein dose and timing are unknown. It is reasonable to start with at least 1.2 g/kg ABW/day in non-obese patients.
Dr. Patel is with the Department of Medicine, Division of Pulmonary, Critical Care, and Sleep Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin.
Dr. Rice is with the Department of Medicine, Division of Pulmonary, Critical Care, and Sleep Medicine, Vanderbilt University, Nashville, Tennessee.