The effect of priming techniques of ultrafiltrators on blood rheology: an in vitro evaluation

The increased interest of using ultrafiltration during cardiopulmonary bypass (CPB) has mandated a re-evaluation of the hematological effects of this blood conservation process. ‘Rinse-free’ ultrafiltrators can be primed using either crystalloid or blood prior to use. It is unknown whether one priming technique results in superior results in ultrafiltration quality. An in vitro circuit was designed to evaluate the Sorin/COBE HC1400 (n=6), the Lifestream HC70 (n=6), and the Terumo/Sarns HC11 (n=6). All test conditions were conducted at a blood flow rate of 250 ml/min and a transmembrane pressure of 250 mmHg. Samples were drawn and analyzed at four distinct time points for hematocrit, total protein, plasma free hemoglobin, interleukin-6 (IL-6), interleukin-8 (IL-8), and tumor necrosis factor-α (TNFα). The HC11 had significantly greater percent increases in hematocrit under the blood priming protocol (29.2 ± 7.9) than either the HC1400 (11.0 ± 7.8, p