[Peroperative echocardiography in cardiac surgery]

Echocardiography is not only useful for pre-operative evaluation of cardiac lesions and to control the quality of some surgical procedures; used peroperatively, it contributes to our knowledge of cardiac function at different stages of the operation. It has taught us that the ischaemic cardiac arrest observed in cardiopulmonary bypass results in reduction of left ventricular compliance and that this can be prevented by potassium-induced cardioplegia. It has also shown that immediately after cardiac valve replacement, the left ventricular "pump" function is reduced in aortic and mitral regurgitation and increased in stenosis. In addition, it has provided evidence that closure of the pericardium and sternum is accompanied with a fall in left ventricular compliance and with disturbances in haemodynamics. The few post-operative studies reported have shown that end-expiratory positive pressure reduces the size of both right and left ventricular cavities. Per--and post--operative studies of left ventricular regional kinetics have not yet been carried out, but this seems to be a good field of application for trans-oesophageal echocardiography.