ABSTRACT
The sympathetic outflow from the spinal cord runs from T1 to L2-3. Spinal anaesthetic techniques (epidural, subdural) using local anaesthetic drugs lignocaine, bupivacaine) may serve to block conduction in preganglionic sympathetic fibres and thus reduce the activity of sympathetic nerves, resulting in vasodilatation. This is of great clinical relevance, and vasodilatation resulting in hypotension is an important component of this type of anaesthesia. The pharmacology of the local anaesthetic drugs concerned is covered in Chapter 36.
