European Journal of Cardio-Thoracic Surgery, Vol 7, 231-234, Copyright © 1993 by European Association for Cardio-thoracic Surgery
Relationship between hemodynamics and blood volume changes after cardiopulmonary bypass during coronary artery bypass grafting
P Kivik
Estonian Heart Center, Tartu University, Tallinn, Estonia.
The blood volume and central hemodynamics were assessed in 22 patients
undergoing coronary artery bypass grafting before and after cardiopulmonary
bypass. Patients were divided into two groups according to their blood
volume after cardiopulmonary bypass. In group A (n = 10) the patients were
hypovolemic and in group B (n = 12) the patients were hypervolemic after
cardiopulmonary bypass. At the same time the mean plasma volume did not
change significantly in group A and increased in group B. Hypovolemia in
group A was accompanied by a significantly lower cardiac index and oxygen
delivery index than in group B. There was a correlation between the changes
in cardiac index and changes in total blood volume (r = 0.57; P < 0.01).
Patients in neither group suffered from hypoxia. We conclude that extreme
hemodilution after cardiopulmonary bypass must be normovolemic, and the
pulmonary capillary wedge pressure or right atrial pressure as a guide for
blood volume evaluation after termination of cardiopulmonary bypass may be
misleading.