Hypermetabolism in the Initial Phase of Intensive Care Is Related to a Poor Outcome in Severe Sepsis Patients

OBJECTIVE: To assess the incidence of hypermetabolism, defined as high resting energy expenditure, in severe sepsis ICU patients, and evaluate the suitability of excessive resting energy expenditure (REE) as a risk factor of their clinical outcome. METHODS: In a single-center, prospective, six-month observational study in China, the measured REE (MREE) was estimated daily using indirect calorimetry (IC) for the first 5 days of ICU admission. The predicted REE (PREE) was determined using the Harris-Benedict equation. ICU severity criteria (APACHE II and SOFA scores), baseline and health characteristics, and laboratory test results, were compared between the hyper-metabolic (MREE/PREE ratio ≥1.3) and the normometabolic (MREE/PREE ratio <1.3) groups, and between the survivor and non-survivor groups, classified according to 28-day mortality. RESULTS: Of the 62 included ICU patients (age, 57.1 ± 19.5 years), 34 patients (55%) were hypermetabolic. The 28-day mortality rate in the hypermetabolic and normometabolic groups was 35 and 18%, respectively (p < 0.001). The MREE/PREE ratio and C-reactive protein (CRP) plasma concentration were significantly higher in non-survivors than survivors (p = 0.017), and were significantly (p < 0.05) associated with 28-day mortality (ORMREE/PREE = 1.018, 95% CI, 1.010-2.544, p = 0.031 and ORCRP = 1.010, 95% CI, 1.005-2.173, p = 0.025, respectively). CONCLUSION: In critical sepsis patients admitted to ICU, the MREE/PREE ratio may be a valuable evaluation index of the clinical outcome.