Transmission of carbonated lidocaine across the placenta during caesarean section.

SEVERAL REPORTS HAVE been published from this department regarding the pharmaeokineties of carbonated lidoeaine base during anaesthesia. 1-a In comparison with the hydroehloride salts, for epidural anaesthesia carbonated solutions of local anaesthetics have been shown to have a decreased latent period for onset of analgesia; a decreased latent period for complete spread of anaesthesia; a decreased requirement of mass of analgesic per spinal segment, and a greater spread of anaesthesia. Lidoeaine CO_,-base has been shown to be non-toxic to neural tissue. 1 Carbonated solutions have been used for analgesia during caesarean section, 2 but maternal and foetal concentrations of lidoeaine base were not determined. This study was undertaken to investigate the vascular uptake of lidoeaine CO2-base during epidural anaesthesia for caesarean section, and to determine whether resulting maternal and foetal lidoeaine concentrations were within safe limits.