In vitro effects of local anaesthetics on the thromboelastographic profile of parturients

Abstract

Background. Post-dural puncture headache can be an incapacitating complication of obstetric epidural analgesia/anaesthesia and early or prophylactic epidural blood patch (EBP) is one of the treatment options. Although local anaesthetic (LA) agents have been shown to have anticoagulation effects in vitro, peri-partum women are known to be hypercoagulable. We postulated that the presence of residual LA might not result in impaired haemostasis of the EBP in parturients. Methods. Blood samples from 10 healthy term parturients were subjected to thromboelastography after the addition of four different LA (lidocaine, bupivacaine, levobupivacaine, and ropivacaine) preparations. Results. There was a significant reduction in reaction (R) and coagulation (K) time (P<0.001, P<0.05) and an increase in α ° angle (P<0.01) when comparing undiluted blood with the saline control group. Maximum amplitude (MA) and clot lysis (Ly30) did not change significantly despite the 50% dilution. The thromboelastographic parameters of all four LA-treated groups were no different from their saline controls and from each other. Conclusion. At clinical dosages, LA did not cause any hypocoagulable changes on the thromboelastographic profile of healthy parturients. © The Board of Management and Trustees of the British Journal of Anaesthesia 2004.