190 E . A . Hayes et al .: J Extra Corpor Technol 2023 , 55 , 189 – 193
Figure 1 . Centrifuge-based plasmapheresis ( left ) and membrane-based plasmapheresis ( right ) circuits incorporated into a cardiopulmonary bypass circuit .
compare the in vitro magnitude of isohemagglutinin titer ( IT ) removal and the time required between MP and CP incorporated into the extracorporeal ( EC ) circuit . While desensitization techniques incorporating MP and CP are utilized prior to transplant , the effects are variable in effect and duration and can be associated with serious complications [ 6 , 7 ]. As transplant timing is difficult to predict , we focused on the feasibility of intraoperative plasmapheresis incorporated into the EC circuits .
Methods
As highly sensitized , high titer donors were needed for this study , blood was obtained from the Red Cross from female donors with blood type O and at least one prior pregnancy . Twelve donor unites of whole blood were purchased and nine of the most sensitized units were pooled for a total volume of 3.5 L in a common reservoir . Heparin Sodium ( Sagent Pharmaceuticals , Schaumburg , IL ) was added to achieve a heparin concentration of 4.0 units / mL , which is standard dosing for cardiopulmonary bypass . Sodium Bicarbonate ( Hospira , Inc ., Lake Forest , IL ) and Calcium Chloride ( American Regent ,
Inc ., Shirley , NY ) were added to achieve physiologically normal blood gases . Once the common reservoir was homogenized ( achieving a final hematocrit of 35 – 55 %), aliquots of 450 mLs were utilized to prime each individual study circuit .
Four identical extracorporeal ( EC ) circuits consisted of a Baby-Fx hard-shell reservoir ( Terumo Cardiovascular , Ann Arbor , MI ), a roller pump ( Getinge , Goteborg , Sweden ), and
1 = 4 inch tubing ( Terumo Cardiovascular , Ann Arbor , MI ) creating a closed loop circuit . Two of the four study circuits incorporated a membrane-based plasmapheresis ( Prismaflex , Baxter Healthcare Corporation , Deerfield , IL ) circuit , and the other two study circuits incorporated a centrifuge-based plasmapheresis ( Spectra Optia Apheresis System , Terumo Blood and Cell Technologies , Inc , Lakewood , CO ) circuit , as demonstrated in Figure 1 . The Prismaflex machine utilized a TPE2000 ( Baxter ) filter for this study .
Blood flow through each of the EC circuits was maintained at 500 mL / min to simulate a 2.2 L / min / m 2 cardiac index for a 4-kilogram patient . The MP circuit flow rates were maintained between 100 – 400 mL / min and the CP circuit flow rates were maintained between 5 – 142 mL / min , according to the manufacturer ’ s instructions for use . Fresh Frozen Plasma ( FFP ) from