Effects of bupivacaine used with sevoflurane on the rhythm and contractility in the isolated rat heart.
OBJECTIVE
The effects of sevoflurane on bupivacaine cardiotoxicity are mainly attributed to systemic effects. The purpose of this study was to investigate the direct myocardial effects of sevoflurane on bupivacaine toxicity.


METHODS
Hearts of 30 Wistar albino rats were isolated and mounted on a Langendorff apparatus perfused by modified Tyrode solution. Experimental groups were: a sevoflurane group (Group S, n = 10)--following baseline and 20 min (Stage 1) recordings, sevoflurane was added in doses of 1.4% (1 MAC) and 2.8% (2 MAC). In the two bupivacaine groups, bupivacaine 5 micromol (Group B5, n = 10) and bupivacaine 10 micromol (Group B10, n = 10) was added to the solution at Stage 1, and sevoflurane was added to the system as in Group S. Haemodynamic variables, i.e. heart rate, PR interval, QRS duration, left ventricular systolic pressure, contractility (+dp/dtmax), relaxation, time to reach peak systolic pressure, change in left ventricular diastolic pressure from baseline, and rate-pressure product were recorded.


RESULTS
In Group S, there was no change in cardiac rhythm. In bupivacaine groups, severe rhythm disturbances occurred and both the PR intervals and QRS complexes were prolonged significantly. All contractility variables deteriorated and the rate-pressure product decreased by 67-90% with the addition of bupivacaine. In all groups, 2 MAC sevoflurane lowered +dp/dtmax further.


CONCLUSIONS
Sevoflurane does not have any untoward effect on bupivacaine-induced cardiotoxicity in clinically relevant doses in the isolated rat heart.
Bozkurt
P
P
Istanbul University Cerrahpaşa Medical Faculty, Department of Anaesthesiology, Istanbul, Turkey. apbs@istanbul.edu.tr
Süzer
O
O
Ekici
E
E
Demirci
O
O
Kaya
G
G
Hacibekiroğlu
M
M
D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D000779:Anesthetics, Local / Q000494:pharmacology*; D000818:Animals; D001145:Arrhythmias, Cardiac / Q000503:physiopathology*; D001283:Atrioventricular Node / Q000503:physiopathology; D001794:Blood Pressure / Q000187:drug effects; D002045:Bupivacaine / Q000494:pharmacology*; D003402:Creatine Kinase / Q000378:metabolism; D004562:Electrocardiography / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects; D066298:In Vitro Techniques; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008297:Male; D008738:Methyl Ethers / Q000494:pharmacology*; D009200:Myocardial Contraction / Q000187:drug effects*; D009206:Myocardium / Q000201:enzymology / Q000473:pathology; D010477:Perfusion; D051381:Rats; D017208:Rats, Wistar; D000077149:Sevoflurane; D016277:Ventricular Function, Left / Q000187:drug effects
D018685:Anesthetics, Inhalation; D000779:Anesthetics, Local; D008738:Methyl Ethers; D000077149:Sevoflurane; D007770:L-Lactate Dehydrogenase; D003402:Creatine Kinase; D002045:Bupivacaine