Thesis
Novel mechanisms for thermal control in ECMO
- Creator
- Rights statement
- Awarding institution
- University of Strathclyde
- Date of award
- 2016
- Thesis identifier
- T14445
- Person Identifier (Local)
- 200990763
- Qualification Level
- Qualification Name
- Department, School or Faculty
- Abstract
- Background Extracorporeal membrane oxygenation (ECMO) is a temporary treatment for patients who suffer from impaired heart- and/or lung functions to degrees of inadequate self-sustainability. The use of an artificial ECMO circuit provides support to the patient to enable the healing processes to occur, with the ultimate objective of returning back to normal organ functions. Since the first application in 1972, ECMO has been responsible for decreasing morbidity in many challenged patient groups, particularly in neonatal care. However, despite the technical advancements, morbidity and mortality rates still remain high, largely based on the invasive nature of the therapy and technical imperfections of the system and the tendency to deploy ECMO as a therapy of last resort. ECMO is associated with many complications, but the focus of this thesis is primarily concerned with the aspects of heat loss. A comprehensive literature review on current ECMO technologies revealed a rather stagnant progression in the evolution of heat exchangers, still employing legacy components dating back to the 1957’s. Moreover, most heat-exchange technologies today rely heavily on external power supplies which limits their use in energy-poor environments. For this reason, two novel solutions for thermal control were proposed, one focusing solely on traditional heat-exchange aspects for conventional hospital based ECMO therapy and the second a solution for energy poor transport settings. Materials and Methods Both heat exchanger concepts that were developed within this project progressed individually, based on their underlying proposed applications. Heat exchanger concept 1 (for conventional ECMO): First, design requirements were established based on desired goals and shortcomings of current heat exchangers. These requirements set the boundaries and formed ideas that were evaluated, refined, and ultimately expressed in form of a finalised CAD drawing. The drawing and the underlying physical effects were modelled and optimised using a computational simulation software in order to minimise time to deploy. Temperature controllers were also designed within the computational domain and the completed, integrated model was simulated and validated with physical laboratory data. After successful validation, our virtual model was manufactured and tested under nearclinical conditions. Heat Exchanger concept 2 (for in-transit ECMO): Similar to the previous strategy, design requirements were established based on expressed clinical aims and implemented in prototype technical drawings. These were used for manufacturing of the device and extensively tested under near-clinical conditions. Results This project has produced two miniaturised medical prototypes for thermal management for very distinct ECMO circumstances; one for conventional ECMO and one for in-transit ECMO. Both devices were computationally and physically tested and the results indicated good agreement with set requirements. Limitations were found with heat exchanger concept 1 during the experimentation phase but were remedied by re-design and further development. A second experiment confirmed efficacy levels that achieved satisfactory results. Heat exchanger concept 2 demonstrated capabilities of adding heat to the system under various ambient conditions and thereby slowing the rate of heat loss from the patient-ECMO system. Supplementary test results indicated the potential for even further reducing the rate of heat loss with the usage of additional low-cost equipment. Through this project, we were able to demonstrate a new direction for thermal management within portable and fixed ECMO settings. This work includes the following: • Design of a novel heat exchanger model with the use of computational simulation software. • Development of a novel and compact heat exchanger for conventional ECMO that does not rely on water supply. • Development of a novel heat exchanger for mobile ECMO applications that is able to significantly reduce heat loss independent of mains or water supply. • Demonstrate high accuracy in model correlation between virtual and physical results.
- Resource Type
- DOI
- Date Created
- 2016
- Former identifier
- 9912537085602996
- Embargo Note
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