Effect of gravity on the spread of extradural anaesthesia for caesarean section.

The effect of gravity on the spread of extradural anaesthesia was evaluated in a series of parturients undergoing elective Caesarean section. Following placement of an extradural catheter, 25 patients were placed 30-40 degrees head-up for 20 min during the administration of the local anaesthetic drug; 25 additional patients remained supine during injection. Extradural anaesthesia was induced with 3% 2-chloroprocaine 23 ml and analgesia to pinprick assessed at 5-min intervals. Additional drug was given after 20 min, if required. There were no differences in the rate of onset of sacral blockade or in the extent of neural blockade between the two groups. The semi-upright position was not necessary to ensure adequate sacral anaesthesia for Caesarean section.