ASAIO journal : a peer-reviewed journal of the American Society for Artificial Internal Organs
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Comparative Study
Efficacy of a heparin removal device in comparison with protamine after hypothermic cardiopulmonary bypass.
To reduce the risks of protamine reactions after cardiopulmonary bypass (CPB), a heparin removal device (HRD) with plasma separation and poly-L-lysine (PLL) affinity adsorption was developed. To compare the efficacy of HRD with that of protamine, blood coagulation variables were evaluated in a swine model of CPB. Female Yorkshire swine were randomly divided into the HRD group (n = 6, weight 79.7 +/- 7.0 kg) and the protamine group (n = 6, weight 79.3 +/- 6.8 kg), and subjected to 60 min of right atrium-to-aortic, hypothermic (28 degrees C) CPB. ⋯ The APTT was not significantly different between the groups at any time during the experiment. Plasma heparin concentration and ACT were not significantly different three hours after the HRD run or protamine administration. The authors conclude that the HRD is capable of predictable reversal of systemic heparinization after CPB, and is an alternative to achieve heparin clearance in subjects who may develop adverse reactions to protamine.
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The authors have synthesized a novel fluorinated polyimide to develop a membrane material for oxygenators and fabricated polyimide hollow fibers for use in an intravascular oxygenator. A dry/wet phase inversion process has been applied to a spinning process to prepare an asymmetric polyimide hollow fiber. The outer surface of the hollow fiber consists of an ultrathin, dense skin layer, with a calculated apparent thickness of approximately 60 nm. ⋯ The blood compatibility of the polyimide hollow fiber without heparinization has been evaluated in vitro. Deformation and aggregation of platelets adherent to the fibers were not observed, and the polyimide suppressed platelet activation. The polyimide significantly reduced the production of anaphylatoxin and also suppressed complement activation.
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A heparin induced thrombocytopenia Type II (HIT) is a dangerous complication of heparin therapy. Bleeding, but above all serious thromboembolic complications, which may result in crippling disabilities or even death, can develop. Twelve heart surgery patients who were diagnosed with a HIT Type II are reported. ⋯ Therefore, these patients must be diagnosed as early as possible. Orgaran along with r-Hirudin are effective heparin substitutes in patients with HIT Type II. These medications can be widely administered to heart surgery patients pre-, intra-, and post operatively without complication.
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Right ventricular assist devices (RVAD) are often needed on a short term basis in patients who develop RV failure after left ventricular assist device (LVAD) implantation. The purpose of this study was to use LVAD filling characteristics to help determine the timing for weaning a patient from RVAD support. Eleven patients (age 50 years +/- 15) supported with an LVAD (Novacor) and an RVAD (Biomedicus or ABIOMED) were studied. ⋯ The LVAD filling was assessed as the first derivative of LVAD volume and the mean filling rate for each cardiac cycle was calculated and averaged over 10 sec periods at both RVAD flows. The mean pump rate corrected filling rates did not change in the RV recovery group (89 +/- 13 vs. 87 +/- 8 ml/beat) and significantly decreased in the RV failure group (84 +/- 19 vs. 62 +/- 22 ml/ beat) (p < 0.001) with decreasing RVAD flow. These data suggest that LVAD filling rates may be used to assess RV systolic function and the proper timing of RVAD removal in selected patients.
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A novel pressure gated tidal flow extracorporeal circulation (TF ECC) device was developed, and it was hypothesized that it could provide total respiratory support in apneic adult sheep without adverse hemodynamic or cardiac effects. The circuit consisted of a single lumen cannula, computer driven tubing occluders gated by circuit pressure, a nonocclusive peristaltic blood pump, a spiral coiled membrane lung, and a heat exchanger. Six paralyzed, anesthetized adult sheep were instrumented and TF ECC was instituted via cannulation of the right atrium. ⋯ Hemodynamic stability was maintained with no significant differences at baseline and after 6 hours in mean arterial pressure, mean pulmonary artery pressure, or heart rate noted. Echocardiographic evaluation showed preserved fractional shortening of the left ventricular (LV) septal-lateral dimension (baseline 32.4 +/- 11.4%; 2 hours 34.8 +/- 8.4%). This study demonstrates TF ECC provides total respiratory support without adverse hemodynamic effects, and preserved LV function.