Nutrition during extracorporeal life support: A review of pathophysiological bases and application of guidelines

Abstract

Background: Patients on extracorporeal life support (ECLS), either for respiratory or cardiac support, are at high risk of malnutrition; guidelines on nutrition in critical care have not incorporated solid evidence regarding these settings. The aim of this narrative review is to gather the available evidence in the existing literature and transpose general principles to the ECLS population.

Methods: A literature review of observational and interventional studies on nutrition during ECLS, and evaluation of nutrition guidelines in this perspective.

Results: Nutrition is paramount for improving outcomes in ECLS, as well as in critically ill patients. The caloric needs during ECLS can vary according to the severity of the clinical state, sedation, paralysis, and temperature stability. Precise evaluation of energy expenditure by indirect calorimetry is difficult because ECLS is a system dedicated to removing carbon dioxide; however, modified equations composed of carbon dioxide values taken from the membrane lung are available. Guidelines suggest starting early enteral nutrition (EN) with a hypocaloric (70%-80% of the needs) strategy, also in acute states such as septic or cardiogenic shock. Moreover, EN, despite previous concerns, is feasible in prone position, an increasingly adopted strategy during mechanical ventilation. The catabolic state is maximal in these patients, causing a protein and muscular reduction. Therefore, adequate protein delivery should be guaranteed by administering a high protein intake of up to 2 g/kg/day.

Conclusions: Studies on nutrition tailored to ECLS patients are warranted. Early hypocaloric EN with high protein intake, tailored on indirect calorimetry, may be the most appropriate option.

Keywords: calories; extracorporeal life support; extracorporeal membrane oxygenation; indirect calorimetry; micronutrients; prone position; protein.