Quartz sensor based approach towards online haemostasis monitoring

• Published in: The Thoracic and Cardiovascular Surgeon
• Main Authors: Stoleriu, MG, Wendel, HP, Walker, T, Schlensak, C
• Format: Conference Proceeding
• Language: English; German
• Published: 01.02.2012
• ISSN: 0171-6425; 1439-1902
• DOI: 10.1055/s-0031-1297583

Objective: Open heart surgery, assist devices, and other long term extracorporeal circulation therapies bear high risks of bleeding and thromboembolic complications. ACT or partial thromboplastin time (PTT) are not suitable for online monitoring, require manual work and yield just a few parameters of the haemostatic system. So, therapies for haemostatic disorders are often chosen without exact knowledge of the exact reasons. The novel technique of a Quartz Crystal Microbalance (QCM) allows simultaneous measurements of several different haemostatic tests out of citrated whole blood and will give sufficient information about complex bleeding complications. Methods: The QCM method permits the detection of any adsorbed masses (cells, proteins, particles, etc) or changes in viscosity in real time by changes in resonance frequency. Protein and cell resistance of hydrophilic and hydrophobic sensor coatings was examined by QCM measurements and accordingly by scanning electron microscopy (SEM). Modified coagulation tests of human whole blood were perfomed with QCM technique to compare the clotting times with those of a commercially available coagulometer. Results: Hydrophilic surface modifications show excellent protein and cell resistance while hydrophobic coatings are less inert concerning protein and cell adsorption. By using whole blood and coagulation activator in 1 + 4 dilutions with physiological buffer it was possible to detect characteristic coagulation signals. QCM based haemostasis measurements show a direct conformity with the coagulation times achieved by conventional coagulometric methods. Conclusion and outlook: The innovative QCM method seems to be suitable for real time investigations of coagulation processes. Furthermore, it is suitable to gain data concerning platelet function, dose rates of heparin and fibrinolysis to enable a complete haemostasis monitoring to start an adequate therapy as fast as possible.