Blood pressure changes during labour and whilst ambulating with combined spinal epidural analgesia

To determine the influence of combined spinal epidural analgesia with fentanyl and low dose bupivacaine on maternal blood pressure and pulse rate in labour. Also, to evaluate the maternal cardiovascular response to mobilising with this form of analgesia in labour. Finally, to define the changes that occur in blood pressure and pulse rate during the second stage of labour and immediately postpartum when using combined spinal epidural analgesia.

A prospective observational study.

Blood pressure and pulse measurements were made at least every 10 minutes, using the SpaceLabs 90207 ambulatory blood pressure monitor, on 62 women in labour with combined spinal epidural analgesia.

A significant fall in systolic blood pressure (> 20%) occurred in eight women (12%), all within 30 minutes of the spinal injection. Fifty-two women subsequently received an epidural dose (mean interval 90 minutes after spinal) and none of these women had a fall in systolic blood pressure of greater than 20%. No women had symptoms related to hypotension. Thirty-five women ambulated for more than 10 minutes on 65 occasions. Average blood pressure remained unchanged while ambulating (126/79 versus 126/79), but pulse rate was significantly increased (85 to 90, P < or = 0.001). The mean blood pressure in the second stage of labour (n = 41) did not rise with pushing (134/83 versus 134/83), but the pulse rate increased significantly (94 to 108, P < or = 0.001). Blood pressure remained unchanged immediately postpartum (n = 33) (134/83 versus 134/81) following ergometrine administration.

The combined spinal epidural analgesia will only result in significant falls in systolic blood pressure within 30 minutes of the spinal injection. No further important changes in blood pressure occur when mobilising or with epidural top-ups. The combined spinal epidural analgesia may modify the normal compensatory mechanisms of blood pressure control, but does not cause significant maternal hypotension once the spinal injection has been given.