(391) Utilization of a Metabolic Cart to Improve Nutrition for ICU Patients

Introduction: The benefits of early nutrition for patients in the intensive care unit (ICU) are well established. However, underfeeding critically ill patients remains a common occurrence in ICUs. One barrier to adequate nutrition administration is the use of predictive equations to determine a patient’s caloric needs. These equations are limited by the multitude of factors that can impact a patient’s metabolic rate, including but not limited to gender, age, pre-hospitalization nutritional state, comorbidities, and current disease course. Alternatively, a metabolic cart, using the principle of indirect calorimetry (IC), allows for real time calculation of a patient’s resting energy expenditure (REE). IC is the gold standard for determining REE. We hypothesized that implementation of a metabolic cart would significantly change a patient’s nutrition plan when compared to the use of standard predictive equations.

Methods: Between November 2022 and July 2023, eligible patients in a mixed medical and surgical ICU at a single center underwent a metabolic cart study with the Ultima CCM™ Indirect Calorimeter (MGC Diagnostics). Inclusion criteria included patients over the age of 18 who were intubated, receiving an FIO2 less than 60%, and receiving artificial nutrition. Exclusion criteria included the presence of chest tubes, hemodynamic instability, and hemodialysis within four hours of planned measurements. Cart studies were performed on two set days of the week and patient eligibility was determined the morning of each testing day. Additionally, REE for all patients was estimated via the Penn State 2003 or Mifflin St Jeor equations.

Results: During the study period, 118 cart studies were performed on 49 patients. 29 patients (59%) were male and 20 patients (41%) were female. On average, REE determined by IC was 153 kCal greater than REE from the predictive equations. Following 65% of the studies (77/118), nutrition therapy was adjusted. None of the 118 studies were terminated early due to patient intolerance.

Conclusions: Measuring REE with a metabolic cart led to a change in the nutrition plan for the majority of patients. The studies were also well tolerated. Further investigation is needed to determine the impact on clinical outcomes for critically ill patients.