Engineering Biomaterials in Advanced Therapy Medical Devices - - PowerPoint PPT Presentation
Engineering Biomaterials in Advanced Therapy Medical Devices Ragnhild E. Aune Dept. of Materials Science and Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, NORWAY 1 1 Introduction In the battle against
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Norwegian University of Science and Technology (NTNU), Trondheim, NORWAY
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diseases doctors have in their arsenal many powerful weapons.
service lifetime of a particular medical device, as well as its association with patients exposure to serious side effects such as: Ø an increased risk of complications (infections, thrombosis, improper healing, cell growth and mechanical failure of the device). Ø decreased quality of life Ø increased suffering Ø prolonged hospital stay.
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and validated methodologies as the basis for appropriate: Ø risk evaluation assessment Ø patient safety assessment in regards to clinical use of medical devices in oncology, respiratory and anesthesia/intensive care.
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Central Venous Line
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Ø How does material degradation affect the performance of the medical device? Ø What are the technical problems caused by materials degradation? Ø How can the rate of decline of performance of the medical device be ensured and evaluated? Ø What should be done to ensure that performance remains far above the critical level for the entire service lifetime of the device? Ø What are the toxic problems caused by medical device degradation?
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SVAPs used in the administration of antineoplastic drugs to women with breast cancer (chemotherapy treatment). In-vitro and In-vivo Settings
Ø exposure of antineoplastic drugs on the inner surface of the catheter Ø exposure of whole blood on the outer surface of the catheter
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compartment that has a silicone septum cover for needle insertion, and a polymer catheter.
skin in the upper chest (or in the arm).
polymers, medical grad stainless steel and medical grad titanium.
study: Polyurethane
SVAP inserted through basilic vein to vena cava superior.
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The use of SVAPs are often associated with an increased risk of complications.
compromise the device and require its surgical removal.
venous and/or in the catheter.
break, usually the attached catheter, and become lodged in the circulatory system.
Wrist and fingers appeared bruised after the SVAP was inserted. Ultrasound image of the upper arm showing a thrombus.
Increased suffering for the patient, a prolonged hospital stay, and higher medical costs.
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Simulation Chamber
SVAPs under well controlled (steady state) conditions ⇒ temperatures (chamber and body), humidity and
flow rate of the drugs. SVAPs
chemotherapy treatment.
NaCl solution.
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administrated in accordance with the protocol for patients treated for breast cancer ⇒ 3 FE100C* + 3 Taxotere treatments (duration 18 weeks).
calculated for the average Scandinavian women (165.5 cm in height and 64.7 kg in weight) resulting in a body surface area of 1.72 cm2.
*A mixture of the drugs ondansetron, betamethasone, fluorouracil, epirubicin and cyclophosphamide
In-vitro
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treatment (after 36 hours and 3 weeks*).
containers in a desiccator outside the simulation chamber.
* Just prior to the next treatment.
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simulated, with a rotating disc (10 rpm) placed in a water bath kept at 37°C.
tubes filled with whole blood from a donor.
In-vitro
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treatment allows for continues evaluation of the inner surface degradation of the material as a function of the direct contact with: Ø the liquid flow itself Ø medical drugs In-vitro
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h e r a p y t r e a t m e n t D u r a t i
s t u d y 1 8 w e e k s Field-Emission Scanning Electron Microscopy (FE-SEM) Noticeable surface alterations.
Exposer to 6 chemotherapy treatments
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In-vitro
whole blood allows for continues evaluation of the outer surface degradation of the material.
the degree of blood clotting formation, as well as the changes of surface morphology.
No prior treatment 6 m i n u t e s i n w h
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Field-Emission Scanning Electron Microscopy (FE-SEM). Blood clots attached to the surface. A drastic increase in porosity.
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In-vitro
incompatibility of the catheter samples post-chemotherapy treatment.
Blood clotting (thrombosis) - Activation of thrombocytes (platelets) and the formation of fibrin. Erytrocyter (red blood cells) Fibrin Trombocyt (platelet)
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alterations of the mechanical properties (with focus on tensile strength and toughness) of the catheter material throughout the duration of chemotherapy treatment.
Decrease in tensile strength already after one treatment. Reference catheter - no prior treatment Catheter exposed to 6 chemotherapy treatments
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Ø Women in the age group 18 - 80 years with invasive breast cancer treated with chemotherapy.
Ø age Ø type of chemotherapy treatment Ø additional medical treatment Ø complications Ø duration of device implanted Ø patients wellbeing/quality of life
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In-vivo
Ø evaluation of material surface alterations as a result of exposer in a patient environment. Ø comparison between in-vitro and iv-vivo results Ø validation of develop methodologies for in-vitro testing
Field-Emission Scanning Electron Microscopy (FE-SEM).
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understanding of the properties, interaction and rate of the use of different medical devices in relation to quality of life, health care costs and the environment.
identification of potential adverse effects from different biomaterials.
different biomaterials in respect to various stakeholders (patient, public authorities, industry, researchers and citizens).
Committee for Standardization (CEN / CENELEC).
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ragnhild.aune@ntnu.no