THE ROLE OF ALPHA(2)-ADRENOCEPTOR-AGONIST CLONIDINE IN CARDIO-ANESTHESIA

At present, clonidine is the only alpha(2)-adrenoceptor-agonist availa ble for clinical anaesthesia. alpha(2)-adrenoceptor-agonists have seda tive and antinociceptive properties, they reduce anaesthetic requireme nts and attenuate haemodynamic and endocrine responses to stressful st imuli, Because of these actions the use of alpha(2)-adrenoceptor-agoni sts as supplements for non-cardiac anaesthesia is well established. Ho wever, many findings give rise to the assumption that alpha(2)-adrenoc eptor-agonists may be useful drugs in cardiac anaesthesia as well. Acc ording to animal studies alpha(2)-adrenoceptor-agonists significantly improve outcome after incomplete cerebral ischaemia. They improve coro nary perfusion and cardiac work indices and decrease the incidence of ischemic myocardial episodes during coronary artery bypass surgery. Ma ny factors deteriorating renal perfusion are counteracted by alpha(2)- adrenoceptor-agonists, It has been shown in patients undergoing corona ry artery bypass surgery that pretreatment with alpha(2)-adrenoceptor- agonists improves renal function after surgery. On the basis of these findings the use of alpha(2)-adrenoceptor-agonists as adjuncts to anes thaesia in cardiac surgical patients may help to improve morbidity and mortality, Outcome studies are necessary to confirm this assumption.