Resting energy expenditure changes related to different sedation levels in critically ill patients undergoing invasive mechanical ventilation

Objective The study aimed to assess the effects of resting energy expenditure (REE) on critically ill individuals requiring mechanical ventilation with different degrees of sedation. Design A prospective self-controlled study was conducted involving 74 critically ill patients with clear consciousness who required mechanical ventilation from September 2023 to September 2024. Sedation was induced and maintained using midazolam, and various levels of sedation were achieved by adjusting the administered dose of midazolam. The level of sedation was evaluated using the Richmond Agitation-Sedation Scale (RASS): mild sedation (RASS score 0–1), moderate sedation (RASS score −2 ~ −3), and severe sedation (RASS score −4 ~ −5). Indirect calorimetry (IC) was employed to assess REE across varying levels of sedation. Results With the increase in sedation, oxygen consumption, carbon dioxide production, and REE gradually decreased. There were significant variations in REE among severe sedation (1,140 ± 108 kcal/d), moderate sedation (1,236 ± 137 kcal/d), and mild sedation (1,347 ± 129 kcal/d) ( p < 0.05). There were no notable differences in the respiratory quotient (RQ) across different degrees of sedation ( p > 0.05). Multiple logistic regression analysis revealed that sedation, sex, age, and body mass index (BMI) were independent factors influencing REE. Conclusion Sedation affected energy expenditure in critically ill individuals who underwent mechanical ventilation, and REE decreased gradually with increasing depth of sedation.