Nutritional adequacy of critically ill patients during their intensive care unit and ward stay promotes survival as biochemical and biophysical profile remains stable: The Dark Side of the Moon study

Abstract

Background: Nutritional therapy guidelines and recommendations for critically ill patients are widely available, yet translating these into effective nutritional interventions remains challenging. Data on the metabolic, physical, and nutritional evolution of Intensive Care Unit (ICU) survivors are scarce. This study aimed to assess energy and protein adequacy both in and out of the ICU and the relationship to outcome, to investigate the metabolism and body composition of ICU survivors.

Methods: This prospective observational study included adult patients with an ICU length of stay (LOS) of ≥7 days. Monitoring commenced on the seventh day of the ICU admission and continued until patients were transferred to the general ward, with the ICU observation period not exceeding 28 days. Subsequently, patients were further monitored at the general ward for a maximum of 28 days or until hospital discharge. Nutritional intake was recorded daily, and energy and protein requirements were determined using either indirect calorimetry (IC) or weight-based formulas. The primary objective was to determine energy and protein intake levels, with a focus on achieving adequacy during both the ICU and ward stay. A comparative analysis evaluated the attainment of adequacy, and its relationship to outcome. Secondary endpoints included assessing the administration of different nutritional routes (oral, enteral, and/or parenteral) and evaluating metabolic changes in the ICU survivors using Bioelectrical Impedance Analysis (BIA) and IC.

Results: Fifty patients were enrolled in the study with complete nutritional data available for 31 patients. The population consisted of 69 % males with an age of 61 (±17) years with a BMI of 28.5 [25-31] kg/m². The LOS at the ICU after inclusion was 6 days [2-13], followed by a LOS of 10 days [7-17] at the ward. at the ICU, the average energy intake was 14 (±8) kcal/kg/day with an energy adequacy level between 80 % (±36) (target 20 kcal/kg/day) and 65 % (±29) (target 25 kcal/kg/day). At the ward, an average energy intake of 15 (±8) kcal/kg/day was noticed with an adequacy level of 58 % (±26). Protein intake was 0.7 (±0.4) g/kg/day at the ICU (target 1.3 g/kg/day) and 0.6 (±0.3) g/kg/day at the ward corresponding to adequacies of 58 % (±30) and 49 % (±23) respectively. No significant differences were observed in energy adequacy or metabolic parameters.

Conclusion: The majority of patients did not achieve the prescribed energy and protein targets during their stays at both the ICU and general ward settings, based on biochemical and biophysical parameters. No significant differences in metabolic changes were observed between the two settings. Finally, logistic regression was performed, showing that ICU survival was significantly affected by both energy adequacy and protein adequacy. This finding appeared to be more prominent in men than in women, especially concerning protein intake.

Keywords: Feeding adequacy; ICU survivors; Intensive care unit; Nutritional therapy.