ABSTRACT
BACKGROUND: Combining bupivacaine with fentanyl for intrathecal analgesia in labor is well recognized, but dosages commonly used are arbitrarily chosen and may be excessive. This study aimed to determine the median effective dose (ED50) of intrathecal bupivacaine, defined as the minimum local analgesic dose (MLAD), and then use this to assess the effect of different doses of fentanyl. METHODS: In this double-blind, randomized, prospective study, 124 parturients receiving combined spinal epidural analgesia at 2-6-cm cervical dilatation were allocated to one of four groups to receive bupivacaine alone or with 5, 15, or 25 microg fentanyl, using the technique of up-down sequential allocation. Analgesic effectiveness was assessed using 100-mm visual analog pain scores, with less than or equal to 10 mm within 15 min defined as effective. MLAD was calculated using the formula of Dixon and Massey. Pruritus and duration of spinal analgesia were also recorded. RESULTS: Minimum local analgesic dose of intrathecal bupivacaine was 1.99 mg (95% confidence interval, 1.71, 2.27). There were similar significant reductions in MLAD (P < 0.001) for all bupivacaine-fentanyl groups compared with bupivacaine control. There was a dose-dependent increase in both pruritus and duration of spinal analgesia with increasing fentanyl (P < 0.0001). CONCLUSION: Under the conditions of this study, the addition of intrathecal fentanyl 5 microg offers a similar significant bupivacaine dose-sparing effect as 15 and 25 microg. Analgesia in the first stage of labor can be achieved using lower doses of fentanyl, resulting in less pruritus but with a shortening of duration of action.
Subject(s)
Analgesia, Epidural , Analgesia, Obstetrical , Analgesics, Opioid/administration & dosage , Anesthetics, Local/administration & dosage , Bupivacaine/administration & dosage , Fentanyl/administration & dosage , Adult , Bupivacaine/adverse effects , Dose-Response Relationship, Drug , Double-Blind Method , Female , Fentanyl/adverse effects , Humans , Pregnancy , Prospective Studies , Pruritus/etiology , Time FactorsABSTRACT
Success of the 'needle-through-needle' technique for combined spinal epidural analgesia requires the immobilisation of the spinal needle during intrathecal injection. A device that achieves this was evaluated in 200 labouring women, randomly allocated to receive a combined spinal epidural using the CSEcure(R) (SIMS Portex, UK) locking needle or a conventional, non-locking technique. Data collection included the incidence of dural click as the spinal needle penetrated the dura mater, presence of cerebrospinal fluid in the spinal needle hub and the number of technical failures with the spinal component. Successful dural punctures with the spinal needle were similar for locking and non-locking needles (99.0 vs. 98.0%; p = 0.55), despite a small but significant reduction in dural click with the locking needle compared with the non-locking technique (97. 0 vs. 84.7%; p < 0.01). Although not statistically significant, there was a higher number of technical failures, mainly due to spinal needle movement, in the non-locking group (9.1 vs. 3.1%; p = 0.08). The locking needle device may be a useful alternative to conventional methods for combined spinal epidural analgesia.
Subject(s)
Analgesia, Obstetrical/instrumentation , Anesthesia, Epidural/instrumentation , Injections, Spinal/instrumentation , Needles , Adult , Equipment Design , Equipment Failure , Female , Humans , Pregnancy , Treatment OutcomeABSTRACT
To assess calculated equivalent doses of intrathecal and epidural opioids for elective Caesarean section in terms of quality and duration of analgesia, and incidence of side effects, we have compared 50 patients, allocated randomly to one of two groups to receive either diamorphine 0.25 mg intrathecally (group 1) or 5 mg epidurally (group 2), in addition to intrathecal bupivacaine 10 mg, using a combined spinal-epidural technique. There was no significant difference in duration of analgesia between groups (group 1 mean 14.6 (SD 5.9) h, group 2 14.2 (6.5) h; mean difference 0.8 h; 95% Cl -2.8-4.5; P = 0.65) or quality of analgesia (VAPS and VRS scores). The degree of pruritus was similar in both groups (80-88%) but the incidence of postoperative nausea and vomiting was significantly higher in the epidural group (24% vs 4%; P < 0.05). Intrathecal diamorphine 0.25 mg produced the same duration and quality of postoperative analgesia as epidural diamorphine 5 mg for elective Caesarean section but with significantly less nausea and vomiting.
