[Timing of a letal intracranial hemorrhage by means of the HbA/HbF ratio (author's transl)].

Possibilities and limits of the method for timing an intracranial hemorrhage by means of the HbA/HbF erythrocyte ratio are investigated in six newborns. The effect of labeling HbF erythrocyte containing newborn blood by transfusion and exchange transfusion of HbA erythrocyte containing donor blood as well as "self-labeling" after the first transfusion as a result of HbA--and HbF erythrocytes decaying at a different rate, is described. If a coagulum can be clearly allocated to the blood where it originates from, depends a) on the alteration of the HbA/HbF erythrocyte ratio by the above mentioned ways of labeling and b) on the size of the sample i.e. on the number of erythrocytes counted to determine the HbA/HbF erythrocyte ratio. The confidence limits of the HbA/HbF erythrocyte ratio for a given number of counted erythrocytes have been determined. It was taken into account whether the blood was labelled by a transfusion or by "self-labeling". The analysis of the period before, during and after the intracranial hemorrhage made a preliminary evaluation of etiological factors and some symptoms possible. The hypothesis that sodium bicarbonate dosages of 8 mEqu/kg/24 h are an important cause of intracranial hemorrhage has to be rejected on the grounds of this study's results.