Influence of Calorie Protein Delivery on Outcomes and Body Composition Changes in the Intensive Care Unit

We conducted a clinical trial (INTACT) to determine if increased calorie delivery from diagnosis of acute lung injury (ALI) through hospital discharge improved clinical outcomes compared to standard care. The trial was stopped early due to significantly greater mortality in the intervention group. The objective of this cohort study of patients who were eligible for INTACT but did not participate was to: determine if increased calorie exposure was associated with higher morbidity/mortality rates (n=298), discern the prevalence of sarcopenia (n=98), and describe changes in skeletal muscle cross-sectional area (SM-CSA) (n=37). Baseline demographics and severity of illness characteristics were recorded at ALI diagnosis. Calorie delivery was collected from 24 hours of ALI diagnosis until extubation. Mortality, ventilation days, length of stay and infection were collected. Participants with one abdominal computed tomography (CT) scan within 4 days of ALI diagnosis were assessed for sarcopenia, defined using skeletal muscle index cut-offs at the third lumbar (L3) region. Changes to L3 SM-CSA was assessed among patients with two CT scans. Logistic and linear regression were utilized to determine predictors of mortality/infection and mechanical ventilation/length of stay, respectively. Cox proportional hazards regression was used to model the relationship between timing of calorie delivery and death. Higher average overall calorie delivery increased the likelihood of death (OR 1.07 95% CI 1.03-1.12). Early calorie exposure (ICU day 1-7) increased (HR 1.04 95% CI 1.01-1.07, p<0.01) while later calorie exposure (ICU day 8+) decreased the hazards of death (HR 0.53 95% CI 0.33-0.84, p<0.01). Higher average calorie delivery also led to longer duration of ventilation and length of stay. A total of 77% (73/95) of patients were classified as sarcopenic by CT scans. Patients lost an average of 0.71% SM-CSA per day. Only severity of illness predicted muscle CSA loss during ICU days 1-7. Energy and protein intake on days 8+ attenuated SM-CSA loss. Increased calorie exposure during the first ICU week does not attenuate SM-CSA loss, increased the hazards of mortality and prolonged mechanical ventilation and length of stay. Calorie delivery after ICU day 8 preserved SM-CSA and was associated with decreased the hazards of death.