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The effect of dextrose administration on glucose production and lipolysis in volunteers with neural blockade (T7-S1)
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Regional Anesthesia and Pain Medicine Vol. 24 No. 3 May-June Supplement 1999
THE EFFECT OF DEXTROSE ADMINISTRATION ON GLUCOSE PRODUCTION AND LIPOLYSIS IN VOLUNTEERS WITH NEURAL BLOCKADE (T7-SI) Franco Carli, M.Phil. I, T. Schricker,
Ph.D. 2, L. Wykes Ph.D. I
1 Professor, 2 Visiting Professor, Department of Anesthesia, McGill University, Royal Victoria Hospital, 687 Pine Avenue West, Montreal, Canada H3A IAI Introduction. Epidural blockade with local anesthetics has been shown to prevent the hyperglycemic response to surgery and to decrease lipolysis (i). The objective of this study was to investigate the effects of epidural blockade on dynamic changes of glucose and glycerol m e t a b o l i s m in the fasted state and during intravenous administration of dextrose in volunteers without superimposed surgical stress. Methods. With the approval of the Ethics Committee of the hospital six healthy volunteers (26 (SD, 6) years) with a body weight of 62 (SD, ii) kg and a height of 173 ( S D , I0) cm were studied. All subjects were admitted twice (one week apart) to the metabolic unit following an overnight fast. Each volunteer was assigned to undergo in random order a control fast/fed study for a total of six hours without (control group) or with epidural blockade (epidural group). In the epidural group a bilateral sensory block was established (T7Sl) with bupivacaine 0.5% and m a i n t a i n e d by infusion of bupivacaine 0.25%. A primed continuous infusion of [6,6-2H2]glucose and [l,l,2,3,3-2Hs]glycerol was delivered over the six hour study period. After three hours of fasted state, dextrose was infused at a rate of 4 mg/kg/min. Blood samples were collected during the last 30 minutes of both fasted and fed states (at isotopic plateau) to measure the rate of endogenous glucose production, the rate of appearance of glycerol, i.e. whole body lipolysis and circulating concentrations of glucose, glycerol, insulin and glucagon. The results are presented as means (i SD). Results. Administration of dextrose significantly inhibited endogenous glucose production from 12.9 (2.2) to 2.2 (2.2) ~mol/kg/min in the control group (p<0.001) and from 12.6 (2.1) to 1.3 (1.2) ~mol/kg/min in the epidural group (p<0.001). Lipolysis in the control group significantly decreased from 1.9 (0.8) to 1.0 (0.5) Bmol/kg/min (p<0.001) and in the epidural group from 2.0 (0.7) to 1.0 (0.2) ~mol/kg/min (p<0.001). Dextrose infusion significantly increased plasma glucose (p<0.001) and insulin concentrations (p<0.001) and decreased plasma glycerol concentration (p<0.05) without showing a n y difference between both groups. Glucagon plasma concentration did not change significantly. Discussion. Epidural block (T7-Sl) with bupivacaine did not affect glucose and glycerol m e t a b o l i s m in volunteers. Mediated through an increase of insulin plasma concentration dextrose infusion suppressed lipolysis and endogenous glucose production to a similar extent in subjects with and without neural blockade. References:
I. Kehlet H, et al: Br J Surg 66:543-546,
1979.
Regional Anesthesia and Pain Medicine Vol. 24 No. 3 May-June Supplement 1999
THE EFFECT OF DEXTROSE ADMINISTRATION ON GLUCOSE PRODUCTION AND LIPOLYSIS IN VOLUNTEERS WITH NEURAL BLOCKADE (T7-SI) Franco Carli, M.Phil. I, T. Schricker,
Ph.D. 2, L. Wykes Ph.D. I
1 Professor, 2 Visiting Professor, Department of Anesthesia, McGill University, Royal Victoria Hospital, 687 Pine Avenue West, Montreal, Canada H3A IAI Introduction. Epidural blockade with local anesthetics has been shown to prevent the hyperglycemic response to surgery and to decrease lipolysis (i). The objective of this study was to investigate the effects of epidural blockade on dynamic changes of glucose and glycerol m e t a b o l i s m in the fasted state and during intravenous administration of dextrose in volunteers without superimposed surgical stress. Methods. With the approval of the Ethics Committee of the hospital six healthy volunteers (26 (SD, 6) years) with a body weight of 62 (SD, ii) kg and a height of 173 ( S D , I0) cm were studied. All subjects were admitted twice (one week apart) to the metabolic unit following an overnight fast. Each volunteer was assigned to undergo in random order a control fast/fed study for a total of six hours without (control group) or with epidural blockade (epidural group). In the epidural group a bilateral sensory block was established (T7Sl) with bupivacaine 0.5% and m a i n t a i n e d by infusion of bupivacaine 0.25%. A primed continuous infusion of [6,6-2H2]glucose and [l,l,2,3,3-2Hs]glycerol was delivered over the six hour study period. After three hours of fasted state, dextrose was infused at a rate of 4 mg/kg/min. Blood samples were collected during the last 30 minutes of both fasted and fed states (at isotopic plateau) to measure the rate of endogenous glucose production, the rate of appearance of glycerol, i.e. whole body lipolysis and circulating concentrations of glucose, glycerol, insulin and glucagon. The results are presented as means (i SD). Results. Administration of dextrose significantly inhibited endogenous glucose production from 12.9 (2.2) to 2.2 (2.2) ~mol/kg/min in the control group (p<0.001) and from 12.6 (2.1) to 1.3 (1.2) ~mol/kg/min in the epidural group (p<0.001). Lipolysis in the control group significantly decreased from 1.9 (0.8) to 1.0 (0.5) Bmol/kg/min (p<0.001) and in the epidural group from 2.0 (0.7) to 1.0 (0.2) ~mol/kg/min (p<0.001). Dextrose infusion significantly increased plasma glucose (p<0.001) and insulin concentrations (p<0.001) and decreased plasma glycerol concentration (p<0.05) without showing a n y difference between both groups. Glucagon plasma concentration did not change significantly. Discussion. Epidural block (T7-Sl) with bupivacaine did not affect glucose and glycerol m e t a b o l i s m in volunteers. Mediated through an increase of insulin plasma concentration dextrose infusion suppressed lipolysis and endogenous glucose production to a similar extent in subjects with and without neural blockade. References:
I. Kehlet H, et al: Br J Surg 66:543-546,
1979.