P.111 PULMONARY GAS EXCHANGES IN EARLY POSTOPERATIVE PATIENTS : EFFECT OF PROPOFOL SEDATION. J.C. Dumont, C. Guidon, M. Alazia, F. Dubouloz, G. Francois. D.A.R. HBpital Adultes La Timone - 13385 Marseille Cedex 05 France.

This study was designed to evaluate the effect of sedation on oxygen uptake (V 02) and carbon dioxid elimination (V CO2) in early postoperative period. 12 patients (8M/4F, age: 59,7 +3,3 years, weight: 72,l + 3,4kg) were studied after a major surgical procedure (vascular : 9, neurologic : 3). Sedation was induced with an IV bolus of propofol (2mg/kg) when patients began to recover from their anaesthesia, and was maintained, for an average of 13 hours, with an IV infusion (3mg/kg/H).V02,VC02 were measured, on mechanical ventilation with an Engstram apparatus, 5 mn before the bolus (To), during the infusion (T5mn, Tlh, T6h), before (Tbefore) and after (Tafter) the end of infusion. Each measurement was performed on a 5mn period.

Results : Ti + SEM

To T5mn Tlh T3h T6h Tbefore Tafter

V 02 282 244* 252* 249" 240* 240* 328" ml/mn +32 +16 514 +15 213 213 +26 - -

w co2 295 199* 206* 204* 196" 198* 258" ml/mn 223 +13 +10 510 +10 +9 219 - -

(paired t - test : *p< 0,005 (vs To); "p< 0,005 (VS Tbefore) Comments : l/ For the two recovery periods (To, Tpost), 102 indicates a high metabolic rate. 2/ During infusion, 802 and VCO2 are significantly lower than at To. In this steady state, energy expenditure, calculated by indirect calorimetry, ranges from 1,05 to 1,lO x BEE (Harris-Benedict).

Conclusion High metabolic rate associated with anaesthesia recovery may be decreased with propofol sedation.

P.112 6NERGY METABOLISM IN SEVERELY :3BESE CHILDREN. B. Schneeweiss, S. Koch, S.Eichinyer, K. Widhalm. Departments of Internal Medicine and Pediatrics, University of Vienna, Vienna, Austria. This study was designed to investigate energy metabolism in severely obese children as compared to an age-matched control group. Energy expenditure and oxidation rates of major fuels were determined by indirect calorimetry ("Metabolic Measurement Cart Horizon", SensorMedics, Anaheim, CA). Fourty- three severely obese children (173?31% recommended weight according Reinken et al. 1978), age 11.9k3.1 years (mean+SD), were studied. The control group consisted of 16 aye-matched (aye 12.124.8 years) normal weight childrens. Studies were performed after an overnight fast. Results (mean+SD):

N Age Weight Heiqht Body surface area recommended weiqht years kg cm ms %

obese 43 11.923.1 78.3t26.3" 155.3t17.8 1.77+0.38" 172.9k30.8 controls 16 12.1t4.8 38.1t16.4 146.4t24.1 1.25_+0.37 94.228.8

Resting energy expenditure RQ Fat Carbohydrate Protein oxidation rate

kcal/min kcal/min/l.73ms percentaqe of total REE obese 1.14+0.27" 1.12kO.12 0.79f0.07- 61.8+22.6- 25.8t21.1" 12.4k5.4 controls 0.78+0.14 1.14kO.19 0.87?0.05 36.4t23.2 53.5k16.4 13.9k7.8 'indcates significant difference (p<O.O5) In conclusion total energy expenditure is increased in obese children as compared to age-matched controls. However, when energy expenditure is corrected by body surface area no difference between adipose and normal weight children existed. Thus, alterations in resting energy expenditure seems not to be involved in the pathogenesis of adipositas in c)iildhood. RQ is reduced in obese children indicating increased fat oxidation rates in these group of patients after an overnight fast.

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