INFLUENCE OF A SINGLE BLOOD DONATION ON T HE CARDIOPULMONARY EXERCISECAPACITY IN YOUNG HEALTHY-SUBJECTS

Autologous blood donation is an established method for an effective re duction of the blood-transfusion-associated infectious diseases (hepat itis, HIV infections, etc.) in elective surgical procedures. The aim o f the study was to investigate the effects of a blood donation of 450 ml on the cardiopulmonary exercise capacity in 16 apparently healthy y oung subjects. The 24 cardiopulmonary exercise tests were performed on a bicycle ergometer (Ergoline 900) in a semisupine position, using a ramp program (+20 watt/min) 1-7 days before and 2 days after blood don ation. By means of continuous breath-by-breath measurements of the gas exchange (VO2, VCO2) and ventilation parameters (minute ventilation V E), as well as of the routine parameters (heart rate, blood pressure, work rate) during incremental exercise the respiratory anaerobic thres hold VO2AT, the maximum VO2 (VO(2 max) and the maximal working capacit y (max. WR) were determined. Serum hemoglobin concentration was signif icantly (p < 0.0005) reduced from 14.5 +/- 1.0 to 13.0 +/- 1.4 g/dl af ter blood donation. The ventilatory anaerobic threshold (before: 68.5 +/- 17.0; after: 52.0 +/- 20.3 % pred. max. VO2), the max. VO2 (before : 124.2 +/- 21.3; after: 110.2 +/-23.2 % pred. max. VO2) and max. WR ( before: 287.1 +/- 75.6; after 265.5 +/- 76.2 watt) fell significantly (VO2AT: p < 0.0005; max. VO2: p < 0.0005; max. WR: p < 0.025). Heart r ate and minute ventilation showed a steeper increase (dHR/dWR: before: 0.31 +/- 0.06; after: 0.34 +/- 0.05 beats/min/watt; dVE/dWR: before: 0.29 +/- 0.05; after: 0.31 +/- 0.05 I/watt) in relation to the increas e in WR after blood donation as compared to the test before. Due to a quicker appearance of the exercise-related metabolic acidosis and a th us reduced VO2AT, ventilation increase during incremental exercise was much higher than before, causing exertional dyspnea in most of the in vestigated subjects.