Issue |
J Extra Corpor Technol
Volume 33, Number 2, June 2001
|
|
---|---|---|
Page(s) | 94 - 99 | |
DOI | https://doi.org/10.1051/ject/200133294 | |
Published online | 14 August 2023 |
Original Article
Effects of Ultrafiltration on Enoxaparin: An In Vitro Analysis
Division of Clinical Perfusion Education, School of Allied Health Professions, University of Nebraska Medical Center, Omaha, Nebraska
* Address correspondence to: Ryan J. Kohtz, MPS, Division of Clinical Perfusion Education, University of Nebraska Medical Center, 985155 Nebraska Medical Center, Omaha, NE 68198-5155. Email: kohtz@unmc.ed
Received:
15
April
2000
Accepted:
31
October
2000
The use of low molecular weight heparins (LMWH) as an anticoagulant in the heparin-resistant patient poses challenges during cardiopulmonary bypass (CPB). The ultrafiltrability of LMWH has not been previously examined. The purpose of this study was to determine the effects of continuous ultrafiltration on the concentraton of a LMWH, enoxaparin. An in vitro analysis was performed using fresh whole human blood and an extracorporeal circuit containing four parallel ultrafiltrators and a cardiotomy reservoir with an integrated heat exchanger. Constant conditions included temperature (37°C), flow (0.20 L-min−1) transmembrane pressure (200 mmHg), and hematocrit (25 ± 2%). Samples were collected at the inlet, outlet, and ultrafiltrate line at one and three min for one control trial and again for each of the four hemoconcentrators following the bolus of enoxaparin. Coagulation measurements included a viscoelastic monitor (TEG), activated clotting time (ACT), activated partial thromboplastin time (aPTT), and quantitative analysis utilizing a membrane-based electrode for potentiometric measurement of polyanionic concentrations of enoxaparin. Enoxaparin concentration, from inlet to outlet, increased from 2.95 ± 0.64 to 5.89 ± 0.95 (p < .001) at 1 min and 4.24 ± 0.49 to 7.89 ± 0.606 (p < .001) at 3 min. Kinetic clot activity, as assessed by the TEG index, decreased from −3.8 ± 2.5 vs. −10.5 ± 6.0; (p < .01) pre- to postultrafiltrator samples after 3 min. ACT and aPTT results demonstrated no significant change. In conclusions, this study demonstrates enoxaparin is concentrated with the use of continuous ultrafiltration. Functional coagulation studies also indicate a concentrating effect, primarily via the TEG.
Key words: ultrafiltration / HIT / low molecular weight heparin / enoxaparin / CPB
© 2001 AMSECT
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