High spinal anaesthesia may block the
nociceptive and haemodynamic responses to common
surgical events such as sternotomy. The extensive sym-
pathectomy provided by high spinal anaesthesia has po-
tential benefits and risks. If cardiac sympathectomy is achieved, there may be improvements in coronary per-
fusion. Stress response may be diminished. However,
when sympathectomy results in excessive hypotension, va-
soconstrictor drugs may be needed. These agents may
have detrimental effects on the coronary circulation, by-
pass grafts, and other organs.30"32
11 Parsonnet V, Dean D, Bernstein AD. A method of uni-
form stratification of risk for evaluating the results of
surgery in acquired adult heart disease. Circulation 1989;
79 (Suppl I): 13-112.
12 Robbins GR, Wynands JE, Whalley DG, et al.