The purposes of this study were to investigate the caloric requirement and clinical outcomes in mechanically ventilated critically ill elderly patients and identify those at high nutritional risk who require high protein formula intervention.

The elderly population is rapidly increasing, but studies on calorie requirement in critically ill elderly patients are few, and indirect calorimetry (IC) is not available in every intensive care unit (ICU). The aim of this study was to compare IC and Harris-Benedict (HB) predictive equation in different BMI (body mass index) groups. And to investigate whether the nutrition intake from EN (enteral nutrition) and PN (parenteral nutrition) created a better clinical outcome than EN alone in HNR (high nutritional risk) mechanically ventilated critically ill elderly patients.Inclusion criteria were: age ≧65 years old, APACHE Π score ≧15, mechanical ventilation ≧48 hours and on NG tube feeding. Nutritional risk was screened by mNUTRIC and GNRI. Indirect calorimetry and HB equation were used to assess energy requirements. Patients were randomized 1:1 to two tube feeding regimens: general formula and high protein formula (1.5~2.0 gm/kg BW). Nutritional intake from EN, the type and amount of intravenous nutrition within 7 days, tolerance to feeding, MVD (Mechanical Ventilation Day), newly diagnosed VAP (Ventilator Associated Pneumonia), ICU and hospital LOS (Length of Stay) and date of death were recorded. We used SAS version 9.4 for statistical analysis. Statistically significance was set at α=0.05.

Inclusion Criteria:

• APACHE Π score ≧ 15
• ≧ 65 years
• on mechanical ventilation ≧48 hours
• received EN

Exclusion Criteria:

• Use of total parenteral nutrition
• Fasting >5 days
• Brain death
• Terminal cancer