ANALGESIA FOR LABOUR AND DELIVERY USING INCREMENTAL DIAMORPHINE AND BUPIVACAINE

Twenty mothers who had requested regional an-algesia during labour had a 32-gauge catheter inserted into the lumbar subarachnoid space. The mean time to place the catheters was 116 s (range 55-270 s) and there were no technical difficulties. Incremental diamorphine was given, up to a maxi-mum initial dose of 0.5 mg. Analgesia was excellent in 11 mothers, good in seven and unsatisfactory in two. The duration of initial analgesia from dia-morphine was 101 min (range 30-170 min). Eight mothers were able to move about during the first stage, with effective analgesia. Side effects were common: 15 mothers hadpruritis, 15 had nausea or vomiting, and eight had mild sedation. No mother had a ventilator / frequency of less than 12 b.p.m. in the 12 h after the last dose of intrathecal dia-morphine. Intrathecal 0.5 % bupivacaine was given to 16 mothers in the first stage because the analgesia after a top-up with diamorphine became insufficient later in the labour. Fifteen mothers were pain free after bupivacaine; there was one failure. The initial effective dose of bupivacaine was between 0.25 ml and 2 ml. The maximum height of the block after bupivacaine was T9, and there was no hypotension. Nine mothers were given hyper-baric 0.5 % bupivacaine 1-2 ml during the second stage; all were pain free for the procedure. The maximum force needed to withdraw the catheters was 700 g; and all catheters were removed intact. There were no post-spinal headaches