Effect of fluid preload on maternal haemodynamics for low-dose epidural analgesia in labour

We prospectively studied 30 women in labour who requested epidural analgesi a. They were randomly allocated into two groups; one received a preload of 7 mL/kg normal saline and the other no preload. All patients had a standard epidural solution consisting of 0.1% bupivacaine 20 mL containing fentanyl 2 mug/mL. Mean arterial blood pressure and cardiac index were measured ser ially for 20 min after epidural drug administration. Cardiac index was meas ured using transthoracic electrical bioimpedance (BOMED). Power calculation showed that a sample size of 30 had 80% power to detect a difference of mo re than 20% in cardiac index using a two-sided test at a significance level of <0.05. No significant changes in cardiac index or mean arterial pressur e occurred at any time in either group. These results suggest that routine fluid preloading is not necessary for 0.1% bupivacaine 20 mL with fentanyl 2 <mu>g/mL as epidural bolus in labour. (C) 2001 Harcourt Publishers Ltd.