P.112 GLUCOSE SYSTEM (GS) VS LIPID-SYSTEM(?)METABO AND RESPIRA- TORY RESPONSES DURING THE EARLY PHASE OF WEANING IN PATIENTS WITH ACUTE EXACERBATION OF CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD).

G.POTEL* +ORDRONNEAU**, F.TASSEAU*, M.CABILLIC**, S.CHOLLET= L.GAUCHEi* .

'Service de Reanimation Polyvalente and '*Service de Pneumo- logie I, University of NANTES, FRANCE.

The purpose of this study was to compare the effects of parenteral GS and LS as non protein-energy source, during the early phase of weaning from the ventilator in patients with COPD. Patients-Methods : 12 non obese patients are mechanically ventilated for acute exacerbation of COPD. 12 hours after admission, VO2 and VC02 are measured. Daily energy expendi- ture (DEE) is then calculated, and the patients are random- ly assigned in two groups ; Group 1 : 100 % glucose calories (1 = 6), or group 2 : 60 % fat (intralipidf), 40 % glucose calories (1 = 6). For each patient, the level of daily calo- ric intake is calculated as DEE + 20 %. _Caloric;nitrogen ratio is 150/ Cal/g N. On the 4th day, V02 and VC02 are re-evaluated, and then artificial ventilation is stopped. Arterial gases and pH are measured every 15 min. during one hour.

Results : VCO2 increases significantly between 1st and 4 th dayonly in GS (130 t 14 ml/min/m2, 170 t 14 ml/min/m2, p < .OOl). This increase is well-correlafed with caloric intake (r = 0,95, p < .Ol). This correlation doesn't exist in LS. When the weaning was begun, PaC02 was higher in GS than in LS (6,5 + 0,7 kPa VS 5,44 t 0,7 kPa, p <.Ol), and after one hour of weaning, PaC02 iricreased more in GS than in LS (p < .05).

p-113 INOIRECT CALORIMETRY (IC) ON MECHAhiCALLY VEblTILATED RABBITS. J.R. Wesley, Y. Tse, R. Dechert, S. LaMond, and R.H. Bartlett (Department of Surgery, University of Michigan, Ann Arbor, Michigan, U.S.A.)

Eight healthy rabbits (2.05-5.65 kg) were used to determine the reproducibility and limitations of a newly developed closed system water-sealed calorimeter for use on mechanically ventilated infants. (.5-l mg/kg/min).

Rabbits were maintained on ketamine hydrochloride Group A rabbits (2.05-2.78 kg) were ventilated at tidal volumes

(VT) of 20 ml and 30 ml. Group B rabbits (3.70-5.65 kg) were similarly tested at tidal volumes of 40 ml and 50 ml. These settings approximate those commonly required in similar weight infants. Measurements were made at 15 minute intervals over 2 hours. Results were:

Group A (N=4) Group B (N=4) VT 20 P 40 P

VOp(ml/min/kg) 17.6 + 2.9 NS l:"l* 2.1 8.421.9 NS 7.::0.8 N= 20 2a 20 20 vco2 8.4*1.7 NS 9.953.2 5.320.9 4.0fl.3 N= 20 20 20 20

This new technique has the advantage of capturing any leak from an uncuffed endo- tracheal tube used in infants. We have demonstrated the capability of determining V02 and VC02 for mechanically ventilated rabbits. The system is safe, has been used successfully on 2 intubated infants, and offers potential advantages for the applica- tion of I.C. for nutritional support in sick infants requiring ventilatory support.

155