Effect of ionic and non-ionic contrast media on red cell deformability in vitro

The effect on red cell deformability from solutions of the ionic contrast media diatrizoate, iocarmate and metrizoate and the non-ionic metrizamide and hypertonic saline (1.5 osm) was investigated by measuring the flow rate of 10% red cell suspension (VRBC) and of plasma (Vplasma) through Nucleopore sieves of 5 micrometer in diameter. By calculating the relative flow rate Vrel (VRBC/Vplasma) the deformability of the red cell was quantified. Both the contrast media solutions and the hypertonic saline solution decreased the Vrel, indicating an increased rigidity of the red cell. The increased rigidity was due mainly to the osmotic effect. The higher the osmolality, the more the deformability was reduced. The low osmotic metrizamide induced a smaller reduction in red cell deformability compared to ionic media of high osmolality in iodine-equivalent concentration.