A double-blind comparison of 0.25% ropivacaine and 0.25% bupivacaine for extradural analgesia in labour.

Ropivacaine is a new aminoamide local anaesthetic. Compared with bupivacaine, ropivacaine possesses a higher threshold for systemic toxicity and a high selectivity for sensory fibres. We have compared prospectively these two agents in a concentration of 0.25% for extradural analgesia in labour. A total of 104 parturients requesting extradural analgesia were randomized to receive either ropivacaine or bupivacaine. The women in the bupivacaine group required more top-up doses to maintain analgesia (median 3.0 vs 2.0) (P < 0.05). The onset of sensory block, quality of analgesia, ultimate level of maximum sensory block and maternal satisfaction were similar in both groups. The incidence, intensity and duration of motor block were slightly but not significantly less in the ropivacaine group. The ropivacaine group had a higher incidence of spontaneous vaginal delivery (70.59% vs 52.00%). There was no significant difference in neonatal outcome as assessed by Apgar scores, umbilical acid-base status and neurological and adaptive capacity score at 2 and 24 h after delivery. We conclude that ropivacaine and bupivacaine in a concentration of 0.25% produced comparable analgesia for pain relief of labour with no detectable adverse effect on the neonate.

Magnetic resonance imaging of extradural blood patches: appearances from 30 min to 18 h.

We have used magnetic resonance imaging to examine five patients treated with extradural blood patches for persistent post lumbar puncture headache. Images were obtained between 30 min and 18 h after patching. Extradural blood patch injection produced a focal haematoma mass around the injection site which initially compressed the thecal sac and nerve roots. The main bulk of the extradural clot extended only three to five spinal segments from the injection site, although small amounts of blood spread more distally. Spread from the injection site was principally cephalad. Mass effect was present at 30 min and 3 h, but clot resolution had occurred by 7 h, leaving a thick layer of mature clot over the dorsal part of the thecal sac. Eighteen hours after injection only small widely distributed clots, adherent to the thecal sac, were demonstrated. Extensive leakage of blood from the injection site into the subcutaneous tissues was present in all patients.

Visualization of extradural blood patch for post lumbar puncture headache by magnetic resonance imaging.

We describe a case of post lumbar puncture headache treated by extradural blood patch. Magnetic resonance imaging (MRI) demonstrated a large extradural haematoma extending over four spinal segments and extending out through the neural outlet foramina. There was significant compression of the thecal sac, supporting the theory that extradural blood patch causes tamponade at the site of dural puncture. The spread of clot was predominantly upwards from the injection site and subarachnoid extension of blood was also demonstrated.

Comparison of the maternal and fetal effects associated with intermittent or continuous infusion of extradural analgesia.

Eighty normal primigravidae received an extradural dose of 0.25% bupivacaine and were then allocated randomly to receive "top-ups" of 0.25% bupivacaine (group A) or an infusion of 0.125% bupivacaine (group B). Group B received supplementary top-ups if required. Group A required more top-ups (147 vs 80) (P < 0.01). No maternal advantage was demonstrated from each regimen. Fetal state was assessed by analysis of the cardiotocograph during labour and the condition of the fetus at delivery. Three different patterns of late deceleratory episodes were identified (grades 1-3). Total numbers of episodes per group were similar (group A, 71; group B, 69). More episodes in group A were related to top-ups (42/71 vs 18/69; P < 0.01) but the incidence of episodes after a top-up was similar (group A, 42/147 (28.6%); group B, 18/80 (22.5%)). In group A, 31/42 events (73.8%) were transient compared with 11/18 persistent episodes (61.1%) (> 10 min duration) in group B. However, the difference in the deceleratory patterns did not influence the condition of the fetuses at delivery.