F J van der Waart | PubMed Health

PubMed1996

Differences in peripheral arterial and venous hemorheologic parameters.

To evaluate the comparability of hemorheologic parameters in arterial and venous blood, we measured hematocrit, whole blood viscosity, plasma viscosity, erythrocyte deformability, erythrocyte aggregation, and erythrocyte indices in both arterial and venous blood from 20 consecutive patients scheduled for coronary artery surgery and/or valve replacement surgery. Hematocrit, whole blood viscosity at three shear rates (0.05 s-1, 0.5 s-1, and 70 s-1), plasma viscosity, and erythrocyte aggregation factor were statistically significantly higher in venous blood than in arterial blood. The differences may be explained by the difference in hematocrit. Erythrocyte deformability did not differ significantly. With the availability of more precise rheological measurement techniques, differences such as those encountered in this study may be of importance in clinical studies. It is concluded that arterial and venous blood samples are not entirely rheologically comparable.

Aged↗

PubMed1995

Systemic haemodynamics and oxygenation during haemodilution in children.

Transfusion of homologous blood should be avoided when possible, and one technique that diminishes perioperative requirement for donor blood is haemodilution. In children its effects on systemic haemodynamics and systemic oxygenation have not been reported. Six children aged 4-12 yr were anaesthetised for major surgery and blood was withdrawn to reduce packed cell volume to 25%. Cardiac index increased from 3.1 (SD 0.5) L min-1 m-2 at baseline to 4.4 (0.5) L min-1 m-2 at the end of surgery, when packed cell volume was 16 (1)%; this change, compensating for the decline in oxygen carrying capacity, was associated with a fall in systemic vascular resistance and a rise in stroke volume. Oxygen extraction from haemoglobin rose from 0.22 (0.05) to 0.33 (0.06). Perioperative blood loss was 40% of circulating blood volume; however, owing to reinfusion of autologous blood (and use of a cell saver in three patients), the haemoglobin one day after operation was only 19% lower than preoperatively (9.9 [1.5] vs 12.5 [2.5] g/dL). In this study, children seemed at least as able as adults to compensate for the effects of haemodilution, which allowed major surgery without transfusion of homologous blood.

Anesthesia↗