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 on patients 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 h 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 kcal/kg [13.0–37.4]. 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.