Cardiopulmonary Bypass in the Setting of Waldenström's Macroglobulinemia.

Waldenström's Macroglobulinemia (WM) is a rare lymphoma caused by the overproduction of immunoglobulin M (IgM). The elevated level of IgM causes serum hyperviscosity, cold agglutinins, and cryoglobulinemia. Anemia is also present because of impaired production of erythrocytes. For these reasons, placing a patient with WM on cardiopulmonary bypass (CPB) requires careful preparation. In this case, the patient was a 73-year-old male with known Waldenström's disease who required coronary artery bypass graft surgery. This report details the perioperative considerations used for successful CPB on a Waldenström's patient. Critical to this case was the use of plasmapheresis before surgery. Temperature management and acid/base status were carefully controlled. A successful coronary revascularization surgery was performed. Many of the Wadenstrom's disease complications expected on CPB failed to materialize.

Darcy Permeability of Hollow Fiber Membrane Bundles Made from Membrana Polymethylpentene Fibers Used in Respiratory Assist Devices.

Hollow fiber membranes (HFMs) are used in blood oxygenators for cardiopulmonary bypass or in next generation artificial lungs. Flow analyses of these devices is typically done using computational fluid dynamics (CFD) modeling HFM bundles as porous media, using a Darcy permeability coefficient estimated from the Blake-Kozeny (BK) equation to account for viscous drag from fibers. We recently published how well this approach can predict Darcy permeability for fiber bundles made from polypropylene HFMs, showing the prediction can be significantly improved using an experimentally derived correlation between the BK constant (A) and bundle porosity (ε). In this study, we assessed how well our correlation for A worked for predicting the Darcy permeability of fiber bundles made from Membrana polymethylpentene (PMP) HFMs, which are increasingly being used clinically. Swatches in the porosity range of 0.4 to 0.8 were assessed in which sheets of fiber were stacked in parallel, perpendicular, and angled configurations. Our previously published correlation predicted Darcy within ±8%. A new correlation based on current and past measured permeability was determined: A = 497ε - 103; using this correlation measured Darcy permeability was within ±6%. This correlation varied from 8% to -3.5% of our prior correlation over the tested porosity range.