Urea-to-Creatinine Ratio as a Marker of Metabolic Transition in Septic Shock: A Comparison With Indirect Calorimetry

Urea-to-Creatinine Ratio as a Marker of Metabolic Transition in Septic Shock: A Comparison with Indirect Calorimetry. This study investigates whether the urea-to-creatinine ratio can serve as a simple marker of metabolic state in patients with septic shock. Septic shock is associated with hypermetabolism and severe protein catabolism, which worsen outcomes. Although indirect calorimetry is the gold standard for measuring energy expenditure and metabolic demand in critically ill patients, its availability in ICUs is limited. The authors hypothesize that the urea-to-creatinine ratio reflects protein catabolism and correlates with energy expenditure measured by indirect calorimetry, making it a potential tool to identify the transition from the catabolic to the anabolic phase and to guide nutritional therapy. The primary objective is to assess the correlation between the urea-to-creatinine ratio and energy expenditure in septic shock patients. Secondary objectives include evaluating changes in systemic inflammation over time using C-reactive protein (CRP). This is a prospective observational cohort study of adult patients with septic shock admitted to a medical-surgical ICU who require at least three days of mechanical ventilation and undergo indirect calorimetry. Energy expenditure will be measured at predefined intervals during the ICU stay, while urea, creatinine, and CRP levels will be collected regularly. Patients with severe renal dysfunction, renal replacement therapy, or high oxygen requirements will be excluded. Data will be analyzed across three time periods during mechanical ventilation to examine trends in energy expenditure, urea-to-creatinine ratio, and inflammation. Demographic and clinical variables will also be collected. The study aims to determine whether changes in the urea-to-creatinine ratio mirror metabolic transitions detected by indirect calorimetry, potentially offering a practical alternative for metabolic monitoring in septic shock patie