Analysis of Resting Energy Expenditure in the Clinical Course of Critically Ill Surgical Patients with Sepsis: Prospective Observational Study

Purpose: It is important to understand changes in energy requirements in critically ill patients with sepsis. This study investigates alterations in energy requirements based on the clinical course of sepsis in patients admitted to the surgical intensive care unit (SICU) using indirect calorimetry.Methods: In this prospective study, 36 patients admitted to the surgical intensive care unit with sepsis were analyzed. Using indirect calorimetry, the resting energy expenditure (REE) and respiratory quotient (RQ) were assessed on the 1st, 3rd, and 7th day of Intensive Care Unit admission. Measured REE through indirect calorimetry was compared with the predictive equations (Weight-based, Harris-Benedict, IretonJones, and Penn state 2003) using intraclass correlation coefficient (ICC) and Bland-Altman analysis.Results: Measured REE was highest on Day 1 and remained unchanged on Day 3 and 7 (Day 1 vs. Day 3 vs. Day 7: 24.29 ± 3.72 kcal/kg vs. 22.42 ± 3.72 kcal/kg vs. 23.26 ± 5.78 kcal/kg). RQ decreased on Day 3 but increased on Day 7 after caloric intake (Day 1 vs. Day 3 vs. Day 7: 0.69 ± 0.06 vs. 0.67 ± 0.05 vs. 0.71 ± 0.06). Comparing the correlation between the 4 predictive equations and the measured REE, the Penn state 2003 equation demonstrated the highest correlation at each time point, although it showed a decreasing trend over time (Penn state equation ICC: Day 1-0.71, Day 3-0.65, Day 7-0.53).Conclusion: In sepsis patients, it is necessary to understand metabolic changes according to the clinical course and provide appropriate calories as determined by using indirect calorimetry when the patients enter the stable phase.