Effects of chronic beta-blockade on compensatory mechanisms during acute isovolaemic haemodilution in patients with coronary artery disease.
We have compared compensatory mechanisms during acute isovolaemic haemodilution of 12 ml/kg body weight of blood with hydroxyethyl starch (450,000/0.7) exchange, in non-beta-blocked and beta-blocked patients with coronary artery disease. During haemodilution, mean concentrations of haemoglobin decreased from 12.8 (SEM 0.2) to 10.1 (0.1) g dl-1 (P < 0.01). Only beta-blocked patients had an increase in cardiac index (P < 0.01); in non-beta-blocked patients, cardiac index remained constant. In both groups oxygen extraction increased (P < 0.01), but the increase tended to be greater in non-beta-blocked patients (P = 0.06). Oxygen consumption was maintained in both groups. There were no ECG signs of myocardial ischaemia. We conclude that beta-blocked and non-beta-blocked patients with coronary artery disease tolerated well moderate haemodilution to a haemoglobin value of approximately 10 g dl-1, however, compensatory haemodynamic mechanisms differed fundamentally between the two groups.
Spahn
D R
DR
Institute of Anaesthesiology, University Hospital, Zürich, Switzerland.
Seifert
B
B
Pasch
T
T
Schmid
E R
ER
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000328:Adult; D000368:Aged; D002302:Cardiac Output / Q000187:drug effects; D001026:Coronary Artery Bypass; D003327:Coronary Disease / Q000503:physiopathology* / Q000601:surgery; D005260:Female; D006438:Hemodilution; D006439:Hemodynamics / Q000187:drug effects*; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000187:drug effects; D011446:Prospective Studies
D000319:Adrenergic beta-Antagonists; D006454:Hemoglobins