Chronic instrumentation techniques for haemodynamic measurements.

Research in chronically instrumented experimental animals has shown basal anaesthesia may cause a considerable disruption of the autonomic control of the cardiovascular system, and a profound change in basal haemodynamics, myocardial function and coronary haemodynamics--variables which are of fundamental importance in studying the impact of various anaesthetics on the cardiovascular system. It is, therefore, important to make sequential haemodynamic measurements which enable comparisons to be made of the conscious v. the anaesthetized state. The present article describes some of the chronic instrumentation techniques used to study the effects of anaesthetic agents on overall haemodynamics, coronary blood flow and regional myocardial function in comparison with the conscious state. It is suggested that the effects of anaesthesia on the integrative control of the circulation are not sufficiently recognized.