The work will allow tracheostomy tubes and endotracheal and tracheobronchial tubes to be introduced into the production of new technology, which is safer for patients.
The author of the thesis entitled: Biological evaluation of selected materials to be used in new technology for the production of tracheostomy tubes and endotracheal and tracheobronchial tubes is Robert Sobota, a doctoral student, an employee of "DEMED" - Department of Medical Details in Mikołów. The thesis was supervised by Prof. Jarosław Markowski, MD, Head of the Department of Laryngology, Faculty of Medical Sciences, Silesian Medical University in Katowice. The associate supervisor was Ewa Janoszek, M.D., from the Department of Medical Details "DEMED" Sp. z. o. o.
What does this innovative work concern? The introduction to production of tracheostomy tubes and endotracheal and tracheobronchial tubes in a new, even better, safer technology for patients.
- For 30 years, tracheostomy tubes as well as endotracheal and tracheobronchial tubes have been manufactured at Zakład Detali Medycznych DEMED Sp. z o.o.. The materials used to manufacture the products are PE-LD polyethylene and silicone rubber, respectively. DEMED is working to introduce a new manufacturing technology for tracheostomy tubes and endotracheal and tracheobronchial tubes. The change in manufacturing technology is necessary for several reasons and involves a change in the materials from which the products will be manufactured. The aim of the study was to evaluate new materials so that they can be used, among others, in everyday medical practice, explains Dr Robert Sobota and adds: - 'A very important, if not the most important reason for changing the technology of producing tracheostomy tubes is to increase the safety of the tube in patients, which would be created as a monolith and not as a connection between the collar and the tube, which generates a potential risk of disconnection of elements.
Products made from the new materials must meet a number of requirements. Also biological. My PhD involves a number of studies on devices, manufactured from selected materials, to determine the feasibility of their use in the manufacturing process. - My main objective was the biological evaluation of tracheostomy tubes and endotracheal T and tracheobronchial Y tubes manufactured from selected materials. First, physical tests were performed on tracheostomy tubes and T and Y tubes to determine the mechanical properties and compare them with those of currently manufactured tubes that are on sale, explains Dr Sobota.
For tracheostomy tubes, polyethylenes were selected (POLI NR1, POLI NR3, POLI NR4), which have food contact approval and, in the case of POLI NR4, the manufacturer declares that it can be used to manufacture medical devices that remain in contact with the body for up to 30 days.
- A thermoplastic elastomer was selected for endotracheal and tracheobronchial tubes, which is a translucent, fully saturated styrene-ethylene-butylene-styrene (SEBS) copolymer. It is available in granular form and is designed for injection moulding. The manufacturer claims excellent resistance to oxidation, ozone and general atmospheric conditions. It is envisaged by the manufacturer for use in construction, medical, general purpose equipment. The material has food contact approval," emphasises Dr Sobota,
The tests covered in the study are part of the bioassessment of the product, which is an extensive process. - A large part of the data to be taken into account in the biological evaluation, such as the configuration of the product, history of clinical use, method of sterilisation, etc., was developed at the beginning of the project in the Department, emphasises Dr Sobota, The project also included the selection of manufacturing technology, the manufacture of injection moulds and many other processes.
Only after obtaining positive results from the subsequent design stages could one move on to the actual chemical, physical or biological tests. The test that initially confirmed the properties of the material selection and gave the "green light" for further research was the chemical evaluation of the selected materials.
What was achieved on the basis of the research carried out during the PhD?
- On the basis of the mechanical tests carried out, it can be concluded that the properties of the tubes manufactured from the selected materials met the required mechanical properties and the products could be subjected to further testing, says Dr Sobota.
The results also showed a lack of cytotoxicity for the polyethylenes and thermoplastic elastomer from which the materials are made. Positive results were also obtained for genotoxicity tests for all materials. Based on the results, interpreted in accordance with ISO 10993-10:2010(E), the tracheostomy tube made from POLI NR 4 showed no irritant effect. In the mouse local lymph node test, tracheostomy tubes made from POLI NR 4 did not induce proliferation (proliferation) of lymphocytes in the lymph nodes at the site of application of the test article and the material should therefore be considered non-sensitising. The tracheobronchial tube Y made of the tested thermoplastic elastomer also did not cause irritant or sensitising reactions.
The final test that was carried out was a study of biofilm formation (a complex multicellular bacterial structure) on the surface of the devices. The study showed that no more biofilm is formed on the surface of tracheostomy tubes, endotracheal tubes and tracheobronchial tubes made from selected materials than on tubes that have been on the market for many years.
The results of biological tests carried out on devices manufactured from the selected materials (POLI NR 4 and thermoplastic elastomer) indicate their biocompatibility (biocompatibility).
- Due to the new normative requirements, appropriate toxicity tests are still needed. If positive test results are obtained, full implementation documentation can be prepared, which will be subject to evaluation by the Notified Body, and implementation of the new technology into the production process can begin, concludes Dr Sobota.
