MECHANICAL HEMOLYSIS BY ARTIFICIAL ORGANS - COMPARISON OF IN-VITRO HEMOLYSIS MEASUREMENTS AND TRANSFER TO IN-VIVO BEHAVIOR

Changes of plasma concentration are often used for in vitro characterisation of the hemolytic potency of artificial organs and apparatus. Different indices of hemolysis are derived from Hb concentration, which, in general, depend on experimental conditions and cannot be compared quantitatively or used to describe the in vivo damage. In this paper we propose a similarity number called ,,lysis number'' that is independent of experimental conditions. It describes the probability for a single blood cell to be completely destroyed in a single pass through the corresponding artificial assist system. The concept is based on the steps: 1. Definition of ,,lysis number'' as an index of hemolytic performance of artificial organs or implants. 2. Description of more complex hemolytic damaging processes (different hemolytic steps) that may be in series or parallel and definition af an effective lysis number. 3. Experimental in vitro estimation of each of the processes in consecutive steps. 4. Calculation of total hemolysis of the complex system using the linkage rules. 5. Application to in vivo by an appropriate differential equation in RBC mas taking into account mechanically-induced hemolysis rate, survival time of normal RBC and erythropoetic generation rate.