Effect of adrenaline on extradural anaesthesia, plasma lignocaine concentrations and the feto-placental unit during elective caesarean section.

Extradural anaesthesia was induced with either 2% lignocaine or 2% lignocaine with adrenaline 1:200,000 in 20 patients undergoing elective Caesarean section. With the adrenaline-containing solution, a smaller dose of lignocaine was required to produce an adequate block and the lignocaine concentrations in both mother and neonate were significantly smaller compared with the plain solution. Arterial pressures were less in the adrenaline group, but there was no difference in umbilical flow velocity waveform, fetal heart rate or fetal outcome. Neither feto-placental circulation nor fetal outcome were affected adversely by episodes of hypotension or the ephedrine used for treatment.