Cardiovascular Effects of Extradural Analgesia in Labour: Comparison of Bupivacaine With Lignocaine

Abstract

Two groups of patients who requested extradural analgesia were studied in a within-patient controlled trial and received either 0.5% bupivacaine with adrenaline 5 mug/ml or 0.5% bupivacaine plain as the analgesic agent (first group) or 0.5% bupivacaine or 2% lignocaine both with adrenaline 5 mug/ml (second group). Arterial pressure, central venous pressure (CVP), maternal and foetal heart rate and uterine contractions were monitored continuously. There was no significant difference in any of the cardiovascular measurements when solutions of 0.5% bupivacaine (with or without adrenaline 5 mug/ml) were used. The second group had a statistically significant increase in CVP during the study period in which 2% lignocaine was used. The position of the patient did not affect the cardiovascular measurements in either group. Since the addition of adrenaline 5 mug/ml to bupivacaine solutions did not confer any apparent advantages, it is concluded that plain solutions of 0.5% bupivacaine should be used except in the longest labours.

Foetal Hypoxia—An Anaesthetist's approach to Classification and Prevention

“…The beta-effects of adrenaline on the heart produce increased heart rate and cardiac output of 49% in non-pregnant subjects when adrenaline 5 fLg/ml was added to 2% lignocaine in the epidural space (Bonica et al 1971). However, Corall et al (1975) found insignificant changes in heart rate, arterial and central venous pressures continuously monitored during labour when adrenaline was added to 0•5% bupivicaine. Ueland et al (1970) noted a marked deterioration in cardiac output following subarachnoid block which did not occur with balanced general anaesthesia and they recommend accordingly the latter for the ill cardiac patient.…”