Echinocytosis induced by haemodialysis.

BACKGROUND

Haemodialysis, widely used to treat patients with renal failure, is not always well tolerated. Different mechanisms have been postulated for this. We analyzed the influence of haemodialysis on erythrocyte morphology and blood rheology.

METHODS

Twenty-two haemodialysed patients were studied immediately before haemodialysis, after 30 min, and at the end of haemodialysis with biocompatible membranes. Haematological routine was measured, the erythrocyte morphology was assessed on glutaraldehyde-fixed cells and blood viscosity was determined.

RESULTS

Erythrocytes underwent various degrees of echinocytic shape transformation after 30 min of haemodialysis, which was completely reversible at the end. In a repetition of the investigations during a subsequent haemodialysis other patients were affected. A plasmatic factor caused echinocytosis since the incubation of control erythrocytes in patients plasma induced a similar, even more marked shape transformation and, vice versa, patient echinocytes regained a discocytic shape when incubated in buffer. The degree of echinocytosis was related to an increased blood viscosity at high shear rates (r=0.800, P<0.01). Echinocytosis was not accompanied by obvious clinical reactions.

CONCLUSIONS

Reversible echinocytosis and an increase in blood viscosity is often seen during haemodialysis, which may affect the circulation in patients at risk.