30ml 0.5% isobaric levobupivacaine over 30ml 0.5% bupivacaine used for interscalene brachial plexus block: Haemodynamic parameters

Abstract

The primary cardiac electrophysiologic effect of local anaesthetic is a decrease in the maximum rate of depolarization in the purkinje fibres and ventricular muscle. This is due to a decrease in the availability of sodium channels. Action potential duration and the effective refractory period is alsodecreased. Sixty patients aged between 18yrs and 60yrs of physical status ASA grade 1 and ASA grade 2 undergoing elective upper limb surgeries were included in the study after ethical clearance from the college ethical committee. Each patient was visited pre-operatively and the procedure explained and written informed consent was obtained. The systolic blood pressure measurement done at various time intervals did not show any statistically significant difference (p>0.05) between the two groups. The diastolic blood pressure measurement done at various time intervals show no statistical difference between the two groups (p>0.05).