IMMEDIATE METABOLIC EFFECTS OF DIFFERENT NUTRITIONAL REGIMENS IN CRITICALLY ILL MEDICAL PATIENTS

Objective: Metabolic effects of different caloric regimens were invest igated in nonsurgical, medical patients with multiple-organ failure (M OF). Design: Seven total parenteral nutrition (TPN) regimens were admi nistered, differing in amount (14, 28, and 56 kcal/kg per day, i.e., h ypo-, iso-, and hypercaloric nutrition, respectively) and distribution [carbohydrates (COH), amino acids (AA), long-chain and medium-chain t riglycerides (LCT/MCT)] of calories. Each regimen was administered ove r 12 h. Metabolism was monitored by energy expenditure (EE), body temp erature (BT), protein breakdown (PB), and blood glucose and serum lact ate levels. Measurements were started within 2 days of MOF onset. Sett ing: The study was conducted in a medical intensive care unit. Patient s: Twenty patients with MOF on mechanical ventilation (mean Apache II score (x) over bar = 26) were investigated. Measurements and results: The mean values of the EE ((x) over bar = 31 kcal/kg per day), BT (x) over bar = 38 degrees C), PB ((x) over bar = 1.5 g/kg per day), and la ctate ((x) over bar = 2.0 mmol/l) and glucose level ((x) over bar = 22 2 mg/dl) parameters were elevated. EE, BT, and lactate and glucose lev els were significantly lower under hypocaloric nutrition than during i so- and hypercaloric nutrition (p < 0.01). Differences in the metaboli c effects of LCT and MCT were not significant. PB was significantly el evated under hypercaloric nutrition (p < 0.01). Protein balance was po sitive under hypercaloric nutrition, and negative under iso- and hypoc aloric nutrition. Conclusions: In nonsurgical, medical patients neithe r hypercaloric nor isocaloric nutritional support prevented protein ca tabolism; in contrast, they enhanced the metabolic burden measured by EE, thermogenesis, urea production rate, and glucose and lactate level s. A hypocaloric regimen is therefore recommended for these patients d uring the early phase of MOF.