0.115 THE EFFECT OF TWO ENERGY SOURCES ON WHOLE BODY PROTEIN METABOLISM IN PATIENTS I-ED

PARENTERALLY. MJ Glynn, S Metzner S, D Halliday, J Powell-Tuck.(Gastrointestinal Unit, Charing Cross Hospital, London; and Clinical Research Centre, Harrow, Middlesex; UK)

The effect of altering the energy source between glucose and fat on whole body protein metabolism has been investigated by a randomised crossover study in 6 non-diabetic patients with total dysphagia, oesophageal rupture, enterocutaneous fistula or pancreatitis undergoing parenteral feeding and in a stable condition. The feeding regimen was kept constant during the 10 days of each study except that for one 5 day period the non-nitrogen energy source was glucose and for the other 5 days it was Intralipid with 1OOg as glucose.

Mean total energy supply was 118kJikgf24h. Blood glucose and plasma insulin concentrations were significantly lower on day 2 of the high fat feed (mean 5mmol/l & ll.luU/ml) compared with day 2 of the glucose feed.(7.6mmol/l & &3.5uU/ml:P<0.01). There were similar statistically significant changes on day 5. Urinary ammonia, total nitrogen and S-methylhistidine excretion, urea excretion corrected for plasma changes, and the urinary S-methylhistidine/creatinine ratio were not significantly different on days 2 & 5 of each period, except that nitrogen excretion on day 2 of the high fat feed was greater (mean 73.1 compared to 61.4 mg/kg/9h:P<0.05).

After a tracer intravenous dose of 15N glycine, rates of whole body protein turnover were measured on day 2 & 5 of each period of the study by methods dependent on the 9h abundances of 15N in urinary ammonia and urinary and plasma urea. There was no significant differences in rates of whole body flux, synthesis and breakdown for the two energy sources on either day with either method. The ratio of the flux determined by the ammonia method to that determined from urea was 1.55 for the feed with glucose and 1.65 when fat was used.

Whole body protein metabolism is therefore not significantly affected by the choice of either glucose or fat as an energy source for parenteral feeding.

0.116 ENERGY EXPENDITURE AND THERMOGENIC EFFECT OF NUTRITION IN LONG-TERM

CRITICALLY ILL TRAUMA-SEPSIS PATIENTS M. Carlsson, A. Thijrne, E. Forsberg (Departments of Anaesthesiology and Surgery, Huddinge University Hospital, Stockholm Sweden)

Hyperalimenation, expecially with glucose, in critically ill patients has adverse effects and the tolerance for excess calories in these patients may be depressed. On the other hand, hypocaloric nutrition does increase protein losses and impair wound healing. The purpose of this study was to measure energy expenditure and the thermogenic effect of nutrition in long-term critically ill patients during mechanical ventilation. Thirteen traumatized and/or septic patients with a mean time of mechanical ventilation of 42 days (range 17-78) were studied. Energy expenditure was measured continuously with the Eng- Strom Metabolic Computer during,4 days in the middle of the period of mechanical venti- lation. An infusion of calories amounting to 105-120% of the measured 24-hour energy expenditure was administered during 14-18 hours. A glucose infusion amounting to 5-10% of total caloric intake was administered during the remaining 6-8 hours (hypocaloric period). Non-protein calories were composed of 50% fat and 50% glucose. Nitrogen intake was 0.15-0.25 g/kg BW. 24-hour energy expenditure was 29 + 4.7 kcaljkg BW (mt SD, range 21-34). Measured energy expenditure was 132t 14% of BMR (Harris-Benedict). TFie energy expenditure of the patients who died (n=3) was 22.7t 1.5 kcal/kg BW, which was signifi- cantly lower (P 0.01) compared to that of the surviTing patients. The increase in energy expenditure during TPN infusion above the hypocaloric period level was used as a measure of the thermogenic effect, although other factors may also have contributed to this increment. During TPN infusion, magnitude of 40% and despite this,

caloric intake exceeded energy expenditure in the the thermogenic effect was no more than lit 7%.

These results indicate that 24-hour energy expenditure in long-term criticaiiy ill patients is lower than in acutely traumatized or septic patients. Therefore, energy ex- penditure should be monitored in order to avoid a caloric infusion rate exceeding the patients' oxidative capacity with the subsequent possibility of unwarranted lipogenesis.

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