Addition of bupivacaine 1.25 mg to fentanyl confers no advantage over fentanyl alone for intrathecal analgesia in early labour.
OBJECTIVE
a) To evaluate the effect of adding 1.25 mg of bupivacaine to intrathecal fentanyl on the duration of analgesia in an Asian population and b) to examine if the baricity of the local anesthetic at this dose has any bearing on the duration and quality of block.


METHODS
Forty-eight parturients in early labour received combined spinal epidural (CSE) analgesia to evaluate a) the effect of adding 1.25 mg of bupivacaine to intrathecal (IT) fentanyl 25 microg on the duration of analgesia and b) the effect of baricity of intrathecal local anesthetic on the duration and quality of the block. Patients were randomly allocated to receive: IT fentanyl 25 microg plus normal saline (Group f, n=16), IT fentanyl 25 microg plus plain bupivacaine 1.25 mg (Group f+pb, n=16) and IT fentanyl 25 microg plus heavy bupivacaine 1.25 mg (Group f+hb, n=16). The two components of the IT injectate (total of 2.25 mL) were given sequentially.


RESULTS
Group f+hb had the lowest sensory dermatomal block (T7 vs T4 (Group f), T5 (Group f+pb), P <0.01). There were no differences in the duration of analgesia and incidence of side effects among the groups.


CONCLUSIONS
We found no advantage of adding 1.25 mg bupivacaine to fentanyl 25 microg. At this dose, the baricity of bupivacaine has no effect on the duration of analgesia.
Lim
Evangeline H L
EH
Department of Anaesthesia, KK Women's and Children's Hospital, Singapore.
Sia
Alex T H
AT
Wong
Kahoe
K
Tan
Hsiao Ming
HM
D000328:Adult; D015360:Analgesia, Epidural; D016362:Analgesia, Obstetrical; D000701:Analgesics, Opioid; D019162:Anesthetics, Combined; D000779:Anesthetics, Local; D001794:Blood Pressure / Q000187:drug effects; D002045:Bupivacaine; D004311:Double-Blind Method; D005260:Female; D005283:Fentanyl; D006801:Humans; D009407:Nerve Block; D010147:Pain Measurement / Q000187:drug effects; D011247:Pregnancy; D011312:Pressure; D013997:Time Factors
D000701:Analgesics, Opioid; D019162:Anesthetics, Combined; D000779:Anesthetics, Local; D005283:Fentanyl; D002045:Bupivacaine