Study of mechanisms of post-transfusion hypertension in thalassaemic patients.

Post-transfusion hypertension, convulsion and cerebral haemorrhage is a serious complication that may occur in the thalassaemias. In this study we evaluated the effect of blood transfusion on blood pressure, plasma renin activity (PRA), blood viscosity, and urinary vanillylmandelic acid (VMA) and catecholamines in 11 beta-thalassaemia/haemoglobin E patients. The results showed that after each unit of blood transfusion the blood viscosity was increased and correlated with the increased in haematocrit level. At the same time the PRA level was significantly decreased and tended to return to the normal level in a few days after the transfusion. There was no alteration in the urinary VMA and catecholamine levels. During the study two patients developed hypertension and headache. Their PRA were still lower than the pre-transfusion levels and the blood pressure returned to the normal pre-transfusion levels within 30-90 minutes after the intravenous injection of furosemide.