Maternal haemodynamic changes during caesarean section: a comparison of epidural and general anaesthesia

Haemodynamic measurements were performed on 20 healthy women before and during elective caesarean section under epidural (10 women) or general anaesthesia (10 women). The influence of the two anaesthetic techniques on the haemodynamic changes associated with operative delivery was compared. The following haemodynamic variables were studied: cardiac output (CO), stroke volume (SV) determined non-invasively with impedance cardiography, heart rate (HR), systolic (SBP) and diastolic blood pressure (DBP), pulse pressure, mean arterial pressure (MAP) and total peripheral vascular resistance (TPR). During epidural anaesthesia, SV was largely unchanged before delivery but increased (P less than 0.05) following delivery. However, CO increased (P less than 0.05) prior to delivery due to an increase (P less than 0.01) in HR. A further increase (P less than 0.05) in CO was recorded following delivery. SBP, DBP, MAP and TPR decreased (P less than 0.01) during epidural anaesthesia. In the patients undergoing general anaesthesia, SV decreased (P less than 0.05) prior to delivery. However, CO remained largely unchanged due to an increase (P less than 0.01) in HR. Following delivery, CO (P less than 0.05) and SV (P less than 0.01) increased whereas HR decreased (P less than 0.01). SBP, DBP and MAP increased (P less than 0.01) prior to delivery, returning to the same level as prior to induction of anaesthesia following delivery. TPR was largely unchanged prior to delivery but decreased (P less than 0.01) following delivery.