Measured resting energy expenditure in cardiothoracic surgery patients and changes throughout hospitalization: A descriptive cohort study.

Abstract

Background & aims: There is a general paucity of data on energy needs during critical illness and the subsequent hospital course, particularly in cardiothoracic surgical patients. We measured resting energy expenditure (mREE) via indirect calorimetry post-cardiothoracic surgery and conducted repeat measures throughout hospitalization to evaluate trends and begin to describe metabolic needs in this patient population.

Methods: Prospective descriptive cohort study design. Patients status post cardiothoracic surgery and admitted to the intensive care unit were enrolled, and indirect calorimetry measurements were obtained within 72 hours post-operative and every 5-7 days thereafter.

Results: A total of 11 patients (4 with obesity and 7 without obesity) and 35 indirect calorimetry measurements were included in the analysis. Overall mean resting energy expenditure was 1598 kcals/day [859-2506], and 21 kcals/kg [13.0-37.4 kcals/kg]. Overall, the patients with obesity had higher resting energy expenditure than those without obesity in kcals/day (1930 vs. 1425, respectively). This trend continued regardless of the patient being in the intensive care unit (obese 1845 kcals/day vs. non-obese 1244 kcals/day) or the step-down unit (obese 2099 kcals/day vs. 1624 kcals/day). Additionally, measurements on the ventilator were lower than those off the ventilator (1310 kcals vs. 1769 kcals, respectively). Inter-patient variability in mREE was diverse, with some energy needs remaining stable throughout hospitalization while others varied greatly.

Conclusions: Measured resting energy expenditure in post-cardiothoracic surgical patients is highly variable. Ventilator and unit status also significantly influenced energy needs, with distinct differences between patients with obesity and those without.