BLOOD-PRESSURE CHANGES DURING LABOR AND WHILE AMBULATING WITH COMBINED SPINAL EPIDURAL ANALGESIA

Objective To determine the influence of combined spinal epidural analg esia with fentanyl and low dose bupivacaine on maternal blood pressure and pulse rate in labour. Also, to evaluate the maternal cardiovascul ar response to mobilising with this form of analgesia in labour. Final ly, to define the changes that occur in blood pressure and pulse rate during the second stage of labour and immediately postpartum when usin g combined spinal epidural analgesia. Design A prospective observation al study. Subjects and methods Blood pressure and pulse measurements w ere made at least every 10 minutes, using the SpaceLabs 90207 ambulato ry blood pressure monitor, on 62 women in labour with combined spinal epidural analgesia. Results A significant fall in systolic blood press ure (> 20 %) occurred in eight women (12 %), all within 30 minutes of the spinal injection. Fifty-two women subsequently received an epidura l 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 m ore than 10 minutes on 65 occasions. Average blood pressure remained u nchanged while ambulating (126/79 versus 126/79), but pulse rate was s ignificantly increased (85 to 90, P less than or equal to 0.001). The mean blood pressure in the second stage of labour (n = 41) did not ris e with pushing (134/83 versus 134/83), but the pulse rate increased si gnificantly (94 to 108, P less than or equal to 0.001). Blood pressure remained unchanged immediately postpartum (n = 33) (134/83 versus 134 /81) following ergometrine administration. Conclusion The combined spi nal epidural analgesia will only result in significant falls in systol ic blood pressure within 30 minutes of the spinal injection. No furthe r important changes in blood pressure occur when mobilising or with ep idural 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.