[Cardioplegic haemoglobin-perfusion for myocardial protection. Experiments on isolated rat-hearts (author's transl)].

On isolated normothermic and constant-pressure perfused rat-hearts cardioplegic haemoglobin-perfusion was compared with conventional cardioplegic perfusion without haemoglobin. The addition of 4% haemoglobin to the cardioplegic solution guarantees oxygen demand of the pharmacologically arrested heart at physiological PO2 (about 100 mm Hg) of the perfusion-solution, while conventional cardioplegic perfusion without haemoglobin needs arterial PO2 > 600 mm Hg and guarantees oxygen demand of the arrested normotherm rat-heart only under condition of sufficient coronary flow. The coronary flow during constant-pressure cardioplegic haemoglobin-perfusion was about 58% higher than during cardioplegic perfusion without haemoglobin. Interstitial oedema after perfusion for 1 hour was more intense after perfusion with the conventional cardioplegic solution than after cardioplegic haemoglobin-perfusion. Normothermic ischaemia of 20 minutes after perfusion with cardioplegic haemoglobin-solution was connected with a smaller drop of creatinephosphate and adenosinetriphosphate than after conventional cardioplegic perfusion, electron-optical preparations showed smaller changes of the structure. The use of cardioplegic haemoglobin-solutions in heart-surgery and the advantages of cardioplegic haemoglobinperfusion are discussed.