[The study of erythrocyte fragility and morphological changes caused by roller pump in vitro]

To observe the erythrocyte fragility and morphological changes of erythrocytes caused by roller pump. Ten tests were divided into two groups, Polystan pediatric pump group A (n = 5) and COBE pump group B (n = 5). Ten whole blood samples (each 400 ml) were circulated in the roller pump for 16 h. Erythrocyte fragility and free hemoglobin were measured before pumping and at every 2 hours during pumping. The possible morphological changes of erythrocytes caused by roller pump were observed by scanning electron microscope. The electron microscopic observation was made before pumping and at every 4 hours throughout pumping. Results showed that the erythrocyte fragility of two groups was not increased during a long period of pumping. The number of acanthocytes of two groups was 1.77/1.81% in the samples before pumping and 6.12/7.13, 9.18/8.73, 13.21/12.89, 16.53/17.21% at 4 h, 8 h, 12 h, and 16 h respectively. The free hemoglobin level of two groups was increased linearly during a long duration of pumping and the index of hemolysis of two groups was 0.296 mg/L/h and 0.3993 mg/L/h respectively. The result shows: 1. the erythrocyte fragility was not increased during a long period of pumping; 2. the erythrocyte membrane was injured or broken by roller pump directly; 3. the morphological changes of erythrocytes would be the basis of post operative hemolysis.