Levels of anaesthesia and intraoperative pain at caesarean section under regional block.

This prospective study recorded levels of analgesia (loss of sharp pin prick sensation) and anaesthesia (loss of touch sensation) in 220 women during caesarean section under regional anaesthesia (70 epidurals, 150 spinals). At delivery the difference between analgesia and anaesthesia varied from 0-7 segments for epidurals and 0-9 segments for spinals. During surgery the level of anaesthesia at the time pain was experienced varied between T5 and T10. No patient with a level of anaesthesia which remained above T5 experienced pain. These results indicate that assessing the adequacy of block by sharp pin prick may be misleading and that in the absence of spinal or epidural narcotics a level of anaesthesia up to and including T5 is required to prevent pain during caesarean section.