Estimation of target calories & proteins achieved in critically ill obese patients receiving enteral nutrition (EN) and its impact on clinical outcomes

Estimation & provision of nutritional support for critically ill obese patients is a challenge due to the unique metabolic changes that occur. This study assesses the target calories & proteins achieved in patients receiving EN & its effect on clinical outcomes in the obese critically ill.

Retrospective study conducted from January 2014 to March 2016 in the ICU of a tertiary care hospital. 35 adult obese patients (BMI≥25) in ICU receiving EN for ≥ 3 days were included. The patients were stratified according to percentage of target calories achieved (Group A<90% & Group B>90%). The goal calories & protein intake for both groups was approximately 20calories & 1.3g/kg of estimated body weight per day. Baseline demographics, nutritional status and EN practice parameters were collected and analysed. The length of stay (LOS) and ventilator free days were evaluated.

24 male & 11 female patients aged 56.6±14y were included. Subjective global assessment revealed that 51% (18) were moderately malnourished. Mean BMI of Group A (n=17) was 29.07±3.93 and that of Group B (n=18) was 27.3±2.56. Group A received an average 72% & 42% (1110±255calories; 43±10.7g) of target calories & proteins in 9.94±4.19days. Group B had higher target calories & proteins of 109% & 71% (1507±188calories; 64±10.2g) delivered in 22±20.9days. In Group B, feeds were initiated later (44.2±103hours) & 72% were on EN for ≥10days in comparison to Group A (28.2±33.4hours & 53%). Mean feed interruption was more in the Group A (25.2±25.8hours). Hypocaloric Group A had a shorter average LOS & higher ventilator free days in ICU (13.5±6.03 & 5.4±18.4 days versus 24.8±21.9 & 4.8±8.08days). Mortality of 26% was observed, of which 23% were male & 3% female.

This study data suggests that hypocaloric EN support in critically ill obese patients may be associated with reduced LOS in the ICU but higher administration of protein can mitigate loss of lean body mass and result in net protein anabolism to improve clinical outcomes.