[How safe is isovolemic hemodilution in elderly patients at risk? Clinical studies of geriatric heart surgery]

The aim of this study was to evaluate isovolaemic haemodilution (IHD) as a method to reduce the use of homologous blood in high-risk geriatric patients undergoing cardiac surgery. Haemodynamics were continuously assessed in both the systemic and the pulmonary circulation, and, in addition, the EEG was continuously analysed by on-line power spectrum analysis. The mean blood use in this series could be reduced from 4.2 units to 1.12 units (67 patients). 73% of the patients needed intraoperatively no blood at all. The haemodynamic response to haemodilution in these patients consisted of an increase in stroke volume by 9%, and decreases in systemic vascular resistance and myocardial-O2 consumption (as reflected by the rate/pressure product RPP) by 9% and 10%, respectively. At the same time, O2 transport capacity increased by 8%. No signs of oxygen balance impairment were found in either ECG or EEG during haemodilution. It is concluded that moderate IHD can be safely performed in the geriatric cardiac patient and represents a useful method to reduce homologous blood use in these patients.