[Effect of anoxia, flow-stop and cardioplegic solutions on the liberation of noradrenaline from the isolated rabbit heart in comparison to clinical findings].
Experiments with isolated hearts. The results include the effects of anoxia, flow-stop and cardioplegic solutions (CPL) on the efflux of noradrenaline (NA) from isolated rabbit hearts preperfused with 3H-noradrenaline. 1.) Anoxic Tyrode solution did not enhance 3H-NA efflux into the perfusion medium. 2.) 3H-NA efflux was greatly enhanced after a flow-stop period of 20 min in normothermia (34 degrees C), but only to a small amount after a flow-stop period of 30 min in hypothermia (10 degrees C). 3.) In flow-stop experiments in hypothermia all CPL solutions enhanced the 3H-NA efflux. This effect is due to sodium deprivation (most CPL) or to high potassium concentration.--Studies on cardiosurgical patients. NA-concentration was determined in blood samples from vena cava superior (zv), radial artery (art) and coronary sinus (cv). 1.) cv NA-level continuously rose from 0.27 ng/ml after induction of anaesthesia to 0.77 ng/ml at onset of complete extracorporeal circulation. 2.) In 19 patients cardioplegia was induced by CPL HTP Bretschneider. Immediately after the cardioplegic period art und cv samples were collected at short intervals. NA-concentrations were not elevated in cv samples. 3.) An increase of NA in cv blood was distinct in two patients with extremely long periods of cardioplegia. In summary, after perfusion of isolated rabbit hearts with hypothermic CPL and subsequent flow-stop, an enhanced NA efflux is evident during reperfusion with Tyrode's solution. The effect of CPL on the NA release seems of minor importance in patients undergoing cardiosurgical procedures.