The feasibility and acceptability of measuring resting energy expenditure using indirect calorimetry in self-ventilating patients following traumatic injury: An observational study (The FAME Trauma study).

Abstract

Indirect calorimetry (IC) is the gold standard method for measuring resting energy expenditure (REE). Although clinical guidelines recommend nutrition be delivered based on measured REE, easily applied predictive equations are most commonly used in practice, with potential for over-and under-estimation of energy needs. We aimed to 1) determine the feasibility and acceptability of using IC to measure REE and 2) compare measured to estimated REE in self-ventilating patients with a traumatic injury. In a single-centre prospective observational study, REE was measured using IC via a canopy hood in patients admitted to a trauma ward with ≥7day hospital stay. Feasibility was set at >50 % of IC measurements being valid (≥5 min with a respiratory quotient between 0.67 - 1.3, and ≤10 % variation in VO₂ and VCO₂). Following the measurement, patients and staff completed an acceptability survey. Measured REE (kcal) was compared to estimated REE (kcal) using predictive equations (Schofield, 25kcal/kg and 30kcal/kg), with ±10 % difference considered clinically significant. Of 30 IC measurements, 25 (83 %) were valid. Measurements were not completed or valid in 5 (17 %) participants due to discomfort (n = 1), pain (n = 1), difficult bedspace (n = 1) and high CO₂ variability (n = 2). Of those that completed the survey, 83 % of participants (n = 24) reported that the test was comfortable, and all staff (n = 11) agreed IC was acceptable to incorporate into usual care. Measured REE was within ±10 % of estimated REE with the Schofield equation, 25 kcal/kg and 30 kcal/kg in 44 %, 28 %, and 60 % cases, respectively. Measured REE using IC is feasible and acceptable following traumatic injury. Estimated REE using predictive equations were not commonly within 10 % of measured REE, which may lead to under or over-feeding of patients following traumatic injury. Further research is warranted to evaluate whether IC-guided energy delivery improves patient outcomes.