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Correction of metabolic acidosis during cardio-pulmonary bypass— A comparison of bicarbonate and THAM
62 CORRECTION OF METABOLIC ACIDOSIS
DURING CARDIO-PULMONARY BYPASS-
A COMPARISON OF BICARBONATE AND THAM H.Brock,H.Ferstl,W.Werth,W.Puchner,H-M. Abt.ftir Anaesthesiologie und operative Introduction An infusion of CO,-generating alkelising agents may eggravate cel&lar acidosis and negatively influence the survival under critical conditions (l).Some authors(2)suggested the use of THAM inste ad of Bicarbonate as an alkalising drug during CPR.In patients with the access to mixed venous blood we tried to find out which one of this two long known agents does show the therapeutic benefits. Methods The group of 24 patients on cardio-pulmonary bypass (CPB) were assigned alternatively totwo collectives and in case of acidosis given either Bicarbonate or THAM.The indications for alkali was simmultaneous finding of pH17.35 and the base deficit25 mEq/l.The both groups were comparable as for age,total operatior time,duration of CPB and aorting clamM,2F ping.The groups differed in sex(l0 in Bicarbonate group;7 M,S F in THAM group)and the art of operation(9 coronary,3 valvular in Eicarb.group and 8 CO,4 valvular in THAM group). ronary Patients’informed
consent
was
obtained.
A standard anaesthesia protocol included high dose of Sufentanil(25 pg/kg)per in. fusion,Pancuronium bromide 0.1 mg/kg and ventilation with air oxygen mixture the CPB the mean of 0.5 FIOz .During pressure was kept between 60-80 mm Hg by flow adjustment and volume if needed The dose of Bicarbonate and THAM was calculated according to known formula(3: The average dose of Bicarbonat was 54.2t13.0 ml and for THAM 15.8f6.0 ml (concentration 1 mmolfml and 3 mmol/ml respectively).Looking for signs of acidosis the erterial and mixed venous blood were sampled every 10 minutes from the CPB start end acid-base end oxygenation examined.Other measurements and calculations were:osmolality,temperature,H+concentration,oxygen trsnsport (DO,),consumption (VO,).The same messurements were repeated in patients needing alkalisation 3 times in 10 minute intsrvals.The statistics was done by t-test for paired values between the zero value(CTRL) and lo,20 and 30 minutes data for Bicarbonate(B) and THAM(T) Results Three sets of changes were observed, these in acid-base balance(l),in O,-con sumption, DO, (2) and in total perfusiol
Kramar,S.Necek Intensivmedizin,AKH
Linz,4020
Linz,Austria
volume on CPB(3). l.The arterial and mixed venous ptl-changes were different than CTRL values,but for B and T not discrepant.The significant venous H+ -concentration changes in nmol/l are shown in the Tab.1 Tab.1 CTRL.
vs. EICARB
10’ 49.9’3.4
46.2*8.9
20’ 49.5*3.;“45.6*6.4 p < 0.05 30’ 48.3t3.1 45.3*6.3 ns.
CTRL vs. THAM 49.k4.1 44.h4.1 p < 0.001 50.4*3.4 45.4t3.9 p < 0.05 51.6t4.2 45.7t7.6 ns.
2.2102 and DOZ were both significantly higher after T (10’ and 20’) ,after B there was solely a VO,-increase without concomitant DO,-raise (20 and 30’). 3.The perfusion volume on CPB had to be increased for 15 % in T patients.It corresponds to 12% increase in DOz in this group.No such perfusion adjustment was necessary after B.The cardiac index postoperatively as compared to pre-CPB was 29% higher after T and not significantly higher after B. Discussion THAM is able to neutralise more Ht than Bicarbonate and this immediately after its application.Its easy access into the cell interior may be responsible for the different way how the 002 is raising, namely wihout increase in oxygen extraction.The adjustment of flow on CPB took place in B and T groups without change in mean perfusion pressure,what implies a fall in peripheral vascular resistance. THAM’s long lasting effect on CI can not be explaind on hand of our present data. Conclusion: Though only mild metabolic acidosis occurred in our study we could see a beneficial effect of THAM as compared to Bicarbonate. In more pronounced acid-base disturbances this effect might show some influence on outcome.
Literature ‘i.Ruiz C.p.Weil M.H..Carlson R.:Iatrosenit alkaiosis end hyperosmolality fillowing CPR.Circulation 6O(P.I1):127,1979 P.Weil M.H.,Rackow E.C.,Trevino R.et al.: Difference in acid-base state between venous and arterial blood during CPR. NEJM,315,153,1986. 3.Heisler N.,Schorer R.:Eine graphische Darstellungsweise des Sgure-Basen-Haushaltes.Anaesthesist 19:93.1970.
DURING CARDIO-PULMONARY BYPASS-
A COMPARISON OF BICARBONATE AND THAM H.Brock,H.Ferstl,W.Werth,W.Puchner,H-M. Abt.ftir Anaesthesiologie und operative Introduction An infusion of CO,-generating alkelising agents may eggravate cel&lar acidosis and negatively influence the survival under critical conditions (l).Some authors(2)suggested the use of THAM inste ad of Bicarbonate as an alkalising drug during CPR.In patients with the access to mixed venous blood we tried to find out which one of this two long known agents does show the therapeutic benefits. Methods The group of 24 patients on cardio-pulmonary bypass (CPB) were assigned alternatively totwo collectives and in case of acidosis given either Bicarbonate or THAM.The indications for alkali was simmultaneous finding of pH17.35 and the base deficit25 mEq/l.The both groups were comparable as for age,total operatior time,duration of CPB and aorting clamM,2F ping.The groups differed in sex(l0 in Bicarbonate group;7 M,S F in THAM group)and the art of operation(9 coronary,3 valvular in Eicarb.group and 8 CO,4 valvular in THAM group). ronary Patients’informed
consent
was
obtained.
A standard anaesthesia protocol included high dose of Sufentanil(25 pg/kg)per in. fusion,Pancuronium bromide 0.1 mg/kg and ventilation with air oxygen mixture the CPB the mean of 0.5 FIOz .During pressure was kept between 60-80 mm Hg by flow adjustment and volume if needed The dose of Bicarbonate and THAM was calculated according to known formula(3: The average dose of Bicarbonat was 54.2t13.0 ml and for THAM 15.8f6.0 ml (concentration 1 mmolfml and 3 mmol/ml respectively).Looking for signs of acidosis the erterial and mixed venous blood were sampled every 10 minutes from the CPB start end acid-base end oxygenation examined.Other measurements and calculations were:osmolality,temperature,H+concentration,oxygen trsnsport (DO,),consumption (VO,).The same messurements were repeated in patients needing alkalisation 3 times in 10 minute intsrvals.The statistics was done by t-test for paired values between the zero value(CTRL) and lo,20 and 30 minutes data for Bicarbonate(B) and THAM(T) Results Three sets of changes were observed, these in acid-base balance(l),in O,-con sumption, DO, (2) and in total perfusiol
Kramar,S.Necek Intensivmedizin,AKH
Linz,4020
Linz,Austria
volume on CPB(3). l.The arterial and mixed venous ptl-changes were different than CTRL values,but for B and T not discrepant.The significant venous H+ -concentration changes in nmol/l are shown in the Tab.1 Tab.1 CTRL.
vs. EICARB
10’ 49.9’3.4
46.2*8.9
20’ 49.5*3.;“45.6*6.4 p < 0.05 30’ 48.3t3.1 45.3*6.3 ns.
CTRL vs. THAM 49.k4.1 44.h4.1 p < 0.001 50.4*3.4 45.4t3.9 p < 0.05 51.6t4.2 45.7t7.6 ns.
2.2102 and DOZ were both significantly higher after T (10’ and 20’) ,after B there was solely a VO,-increase without concomitant DO,-raise (20 and 30’). 3.The perfusion volume on CPB had to be increased for 15 % in T patients.It corresponds to 12% increase in DOz in this group.No such perfusion adjustment was necessary after B.The cardiac index postoperatively as compared to pre-CPB was 29% higher after T and not significantly higher after B. Discussion THAM is able to neutralise more Ht than Bicarbonate and this immediately after its application.Its easy access into the cell interior may be responsible for the different way how the 002 is raising, namely wihout increase in oxygen extraction.The adjustment of flow on CPB took place in B and T groups without change in mean perfusion pressure,what implies a fall in peripheral vascular resistance. THAM’s long lasting effect on CI can not be explaind on hand of our present data. Conclusion: Though only mild metabolic acidosis occurred in our study we could see a beneficial effect of THAM as compared to Bicarbonate. In more pronounced acid-base disturbances this effect might show some influence on outcome.
Literature ‘i.Ruiz C.p.Weil M.H..Carlson R.:Iatrosenit alkaiosis end hyperosmolality fillowing CPR.Circulation 6O(P.I1):127,1979 P.Weil M.H.,Rackow E.C.,Trevino R.et al.: Difference in acid-base state between venous and arterial blood during CPR. NEJM,315,153,1986. 3.Heisler N.,Schorer R.:Eine graphische Darstellungsweise des Sgure-Basen-Haushaltes.Anaesthesist 19:93.1970.