Prediction of Critical Time in Anoxic Myocardium or Brain by Automatically Evaluated Oxygen Chronopotentiometry

Abstract

A technique has been developed to make estimates of the safe duration of anoxic heart arrest during open heart surgery. It can be applied for monitoring of critical states in other organs. Its principle is the determination of tissue resistance and the polarization of a platinum electrode, using current chronopotentiometry, automatic evaluation of the critical time for the duration of hypoxia or anoxia. The chronopotentiometry of oxygen and hydrogen ions using a blank platinum semi-microelectrode and controlled current offers some advantages over classical controlled voltage polarography. In open heart surgery the method has enabled us to achieve complete resuscitation and recover in 90% of experimental animals if the critical time was not surpassed. Each time the anoxic period was longer than the critical time, resuscitation was not possible. The evalutiona of critical time is done by computational methods. Possibilities of automatic evaluation by purpose-built hardware are envisaged.