Particle release from haemodialysers.

Release of particles from eight makes of hollow-fibre and one make of flatplate dialyser have been studied, and the relationship between rinsing volume and particles recovered established. In a supplementary study the effect on the number of particles released was assessed when striking the dialyser header during priming. Particle size distribution indicated that the majority of the particles recovered were less than 5 microns in diameter. A separate analysis of the particles in the 5-30 micron size range showed two different patterns of particle release. In the dialysers containing ethylene vinyl acetate (EVAL) or Cellulate the number of particles recovered were within the 95% range of the particles in the rinsing fluid and did not alter with increasing rinsing volume. In the dialysers containing Cuprophan and Hemophan the initial particle numbers were higher but fell rapidly up to a 450 ml rinse volume; increasing the rinse volume to 1050 ml did not alter particle recovery. Analysis of variance failed to differentiate between individual dialysers. Striking the header during priming resulted in a transient statistically nonsignificant increase in the number of particles recovered.