Validation of the V max Metabolic Cart in a Simulated Pediatric Model

Abstract

Background: The ability to accurately measure resting energy expenditure (REE) using indirect calorimetry, often referred to as the “gold standard” in nutrition needs assessment, is important given the well-established positive correlation between patient outcome and proportion of the nutrition goal met. While many studies have been done to compare various metabolic carts with one another, the literature lacks a large simulator-based validation of any metabolic cart system. Materials and Methods: In the present study, 8 specifically trained staff members independently conducted 10 simulation trials each using the V_max Encore metabolic analyzer in conjunction with a metabolic calibration system, which simulates patient metabolic activity, to validate the accuracy of the V_max Encore across a wide range of simulated metabolic conditions. Testing conditions consisted of incremental adjustments in calibrated gas infusion with a consistently set tidal volume and respiratory rate. Results: There was a strong, statistically significant correlation between the predicted and actual VO₂ and VCO₂ data (VO₂, R² = 0.998; VCO₂, R² = 0.997). In addition, we observed no significant difference between individuals performing these trials (VO₂, P = 1.000, F = 0.021, df = 79; VCO₂, P = 1.000, F = 0.030, df = 79). Conclusions: This study is the first to report on such a wide spectrum of metabolic activity (50–2000 kcal REE) using a calibrated bench model and validates the accuracy, reproducibility, and use of the V_max Encore metabolic cart.