Assessment of achieving energy and nutrient intake targets in intensive care patients: İndirect calorimetry vs. formulas

Indirect calorimetry (IC) is considered the gold standard for measuring basal energy expenditure in intensive care unit (ICU) patients. This study was planned to compare the measurement of basal energy expenditure using Indirect Calorimetry with various formula-based estimated energy requirements and daily energy intake in stable ICU patients receiving mechanical ventilation support at Kayseri City Hospital ICU units. Additionally, the study aimed to evaluate the nutrition plans provided to patients through enteral or parenteral routes in conjunction with the measurements (IC, Harris Benedict formula, and ESPEN guidelines). The study was conducted on 70 patients, with 42 (60%) being male and 28 (40%) female. Indirect Calorimetry measurements were performed on 38 patients for 15 minutes. Basal energy expenditure was also measured using the Harris Benedict formula for 32 patients. Demographic characteristics, anthropometric measurements, information related to the ICU stay, nutrition plans of patients, and laboratory findings were recorded via literatüre-based a questionnaire. To assess the patients' disease and mortality status, SOFA and APACHE II scores were used, while PNI and m-Nutric scores were employed to determine their nutritional risk status. The energy requirement value obtained using the energy requirement formula recommended in the ESPEN guideline (25-30 kcal/kg/day) (1812.50 (1586.75-2156.25)) was found to be significantly higher compared to the basal energy expenditure measured with indirect calorimetry (1470.00 (1243.00-1848.25)) and the basal energy expenditure calculated using the Harris-Benedict formula (1765.00 (1630.75-2042.00)) (p<0.05). As a result of the study, it was concluded that basal energy expenditure measured with indirect calorimetry was lower than that predicted by formulas. This indicates that individual results differ from formulas and can impact the nutritional status of patients, emphasizing the need for individualized measurements for each patient. Keywords: Intensive Care, Indirect Calorimetry, Harris Benedict Formula, Mechanical Ventilator, PNI, m-Nutric, Basal Energy Expenditure.