Adequacy of protein and calorie delivery according to the expected calculated targets: a day‐by‐day assessment in critically ill patients undergoing enteral feeding

Background In critically ill patients requiring mechanical ventilation for longer than 48–72 h enteral nutrition (EN) should be started early. Because EN alone may be unable to reach the target nutritional requirement, supplemental parenteral nutrition (PN) should be administered. This study aimed at describing the daily rate of administered calories and proteins according to the expected calculated targets. The impact of calorie adequacy, deficit or excess on relevant clinical outcomes was explored. Methods A retrospective cohort study was conducted in 217 patients undergoing cardiac surgery, admitted postoperatively in intensive care unit and undergoing EN. The effective intake provided via EN, PN, oral nutritional supplements (ONS) and nonnutritional calories (NNC) was documented for a maximum of 20 days. The administered/required calorie and protein ratios (KcalA/R, ProtA/R) were calculated daily. Patients receiving 80%–100%, 100% of KcalA/R and ProtA/R were identified. The association between mean KcalA/R between days 4–7 and 30 days’ mortality was explored. Results A mean KcalA/R ratio of 92.0 ± 40.6% was ensured between days 4 and 20. During days 4–7 the 80%–100% calorie target was achieved in 26.9% of patients, whereas 44.9% were below and 28.2% over this range. EN contributed 47.1% and PN 41.2% to the total energy intake. An increase in 30‐day mortality risk was documented for patients exceeding 100% of KcalA/R ratio (adjusted‐hazard ratio [HR] 5.2; 95% confidence interval [CI] 1.1 –23.9; p = 0.035). Conclusions Despite a preliminary estimate of nutritional requirement, a steady daily optimal 80%–100% KcalA/R was not ensured for all patients. EN contributed only partially to both energy and protein intakes so that PN was largely used to achieve the desired nutritional targets. Key points In critically ill patients requiring prolonged mechanical ventilation, inadequate nutritional support may worsen inflammation, hypermetabolism and catabolism, and thus negatively affect the outcome. The present investigation provides new evidence in describing the daily specific contribution of all nutritional sources to total nutritional requirements in postoperative cardiac surgery patients undergoing enteral nutrition.