Outcome measures and data collection
The primary outcome of this study was IL-6, CRP, SOFA, and APACHEII. A checklist was designed to obtain information according to the selection criteria of the study including age, sex, medical history, drug history, and underlying diseases. Disease severity scores, including the acute physiology and chronic health evaluation (APACHE) and sequential organ failure assessment (SOFA) scores were calculated. The weight (using bed scales; Seca-Germany), estimated height, NUTRIC score, required energy intake and received energy (Kcal/kg/day) were also calculated by the nutritionist for each patient and all patients received standard hospital gavages. Serum and plasma were extracted from the blood samples by adding EDTA and centrifugation at 3000 rpm for 15 minutes at 4 ºC. Plasma samples were stored at -80 ºC immediately after centrifugation until analysis.
After the finishing of intervention, serum CRP level was measured following the method of immunoturbidity measurement (Kit: Quantitative determination of CRP in human blood by latex turbidimetry assay using BT3500 Biotecnica Instruments SpA –Italy). IL-6 as an inflammatory marker measured by ELISA method using Karmagene kit (Kerman-Iran), and also 28-day mortality was measured and recorded by telephone and follow-up of patients after intervention.