Energy Expenditure and Nutritional Therapy in Critically Ill Patients

Abstract

Providing adequate nutrition has become an extremely important issue
in critically ill patients. We found that caloric requirements were met in
only one of four mechanically ventilated patients in our intensive care
unit (ICU). This nutritional imbalance mainly resulted from incorrect
prescription.
To improve prescriptions, we introduced an evidence-based protocol
and indirect calorimetry (IC). An extensive feasibility study revealed
that IC was indicated in half of the patients and effectively performed
in 20%. IC proved to be technically feasible and was not timeconsuming.
In current ICU practice, mathematical equations are used to estimate
energy requirements. We assessed whether IC measurements agreed
with the results of ten distinct predictive equations. Only a weak
correlation was found. If used as a nutritional target, calculated energy
expenditure would result in significant under- and overfeeding.
To date, mathematical equations are applied for estimating metabolic
rate in patients treated with extracorporeal membrane oxygenation
(ECMO) and continuous renal replacement therapy (CRRT). Performing
IC is complex during ECMO since gas exchange is divided between the
mechanical ventilator and the artificial lung. We developed and report
preliminary clinical experience with a novel technical set-up to measure
gas exchange in both devices. In addition, we propose a theoretical
model to derive energy expenditure by incorporating acquired data in
an adjusted formula.
We reviewed the literature on nutrition in ICU patients treated with
CRRT. Feeding these patients is challenging since both kidney injury
and CRRT induce substantial metabolic disturbances. We make clinical
recommendations for handling requirements in energy, protein,
electrolytes, glucose, amino acids, lipids, vitamins and trace-elements
in patients undergoing CRRT. The implementation of the results of
these five studies improves the level of care of critically ill patients.

Date of Award	2 Dec 2015
Original language	English
Supervisor	Luc Huyghens (Promotor), Herbert Spapen (Promotor), Patrick Honore (Promotor), Brigitte Velkeniers-Hoebanckx (Jury), Hendrik Reynaert (Jury), Christian Simoens (Jury), Ives Hubloue (Jury), Pierre Singer (Jury), Alain Dive (Jury) & Jan De Waele (Jury)