Epidural volume extension does not provide superior analgesia with a combined spinal-epidural technique for women in labour, according to a study presented here at the 2014 Annual Meeting of the Canadian Anesthesiologists’ Society (CAS).
Presentation title: A Randomized Controlled Trial of Epidural Volume Extension During a Combined Spinal-Epidural Technique for Labour Analgesia. Abstract 38998
Epidural volume extension involves an injection of saline to provide additional volume into the epidural space, compressing the dural sac, which causes cephalad shift of the cerebrospinal fluid, explained lead author Valerie Zaphiratos, MD, Hôpital Maisonneuve-Rosemont, Montreal, Quebec, on June 15.
Dr. Zaphiratos and colleagues hypothesised that epidural volume extension with 10 ml of normal saline during a combined spinal-epidural technique would increase the anaesthetic sensory block height, decrease pain scores, decrease pain scores more rapidly, and decrease motor block compared with performing combined spinal-epidural without epidural volume extension. The primary outcome measure in this study was the difference in sensory dermatome level.
The trial involved 54 healthy, full-term, nulliparous parturients with a cervical dilation of <5 cm. The women received intrathecal analgesia of bupivacaine 2 mg and fentanyl 10 µg and were randomly allocated to not receive (n = 28) or to receive (n = 26) epidural volume extension with 10 ml of normal saline delivered through a Tuohy needle before insertion of an epidural catheter. Each catheter was threaded 5 cm into the epidural space, and a standard continuous epidural infusion was started.
A blinded researcher assessed the sensory dermatome level by a nontraumatic blunt pinprick test, analgesia by a numeric rating scale (0-10), and motor blockade with a Bromage score of 1 to 6 at 2.5-minute intervals.
The results showed that there were no significant differences in peak dermatome levels between the women with and those without epidural volume extension at 15 and 30 minutes (P = .2234 and .7589, respectively). Time to peak dermatome also did not display a significant difference between the groups (P = .8266). Furthermore, no difference was evident in the minimum pain score (P = .1958) or the time to minimum pain (P = 1.0000) between the groups.
Fewer parturients receiving epidural volume extension (n = 3) than not receiving the treatment (n = 6) had a Bromage score of <6, indicating a trend toward less motor block, but this was not statistically significant (P = .1029).
Long-term catheter function was not assessed.
There were no significant differences in demographic criteria between the 2 groups in this study.
Combined spinal-epidural is a popular way of delivering analgesia during labour. Benefits include rapid onset of profound analgesia, minimal motor blockade, and high patient satisfaction.
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