Optimising the Design of a Medical Device Intended for Use in Low- and Middle Income Countries

Abstract

Introduction: Smart Medics Company is a startup from the Delft University of Technology, looking to bring an affordable Video laryngoscope (VL) into hospitals in low-resource regions. This research aims to seek the best suitable transparent material to act as a lens, sealing off a compartment containing an endoscope, as well as, bring forth a design optimisation that will create a waterproof environment for the incorporated electronics and prepare the device for disinfection according to the used disinfection procedures in low-resource regions. Method: Two approaches have been used to investigate the opportunities. The first approach was by using quantitative research, where glass and polymethylmethacrylate (pmma) were subjected to the disinfection chemicals used in hospitals in low-resource regions. These chemicals included, CIDEX® OPA, Isopropanol and JIK (3.5% active chlorine). This was done in three different experiments, the first experiment was conducted to find the short-term effects of the used chemicals. The second experiment was conducted to see the effect of rinsing with water in between the cycles, and the third experiment revealed the long-term effects of the used chemicals on glass and pmma. Furthermore, prices per material were compared to find the material with the best price-durability ratio. The second approach was by means of qualitative research. To generate optimisations for the current design of the VL, three methods were used. The first method, a state-of-the-art research combined with a literature search to find solutions that could aid in the process of designing. The second method was the usage of a morphological overview, to generate concepts according to the necessary requirements. Thirdly a Harris profile was created to score the concepts conforming to the context in which the VL will be placed in. Additionally the option to creating a wireless design along with the best method to incorporate the lens into the design were investigated. Results: Regarding the chemical resistance of both glass and pmma, they both showed to be resistant to the used chemicals. Although pmma showed a form of solvent crazing in the first two experiments, it did not show this in the third experiment, therefore, it is thought that the samples of the first two experiments were contaminated causing this phenomenon. Regarding the price-durability ratio, pmma scores the best as, for the price of one glass lens, 590 pmma lenses could be fabricated. The qualitative research generated three feasible designs, all three with unique features, in terms of connectivity, power and the disinfection process. The state-of-the-art technology inquiry presented multiple innovative patents that aided during the conceptualisation. The scoring according to the Harris profile revealed the applicability to the desired context. One of the concepts included a wireless design which was evaluated to see how feasible a wireless design would be in this context. This showed that although it was feasible, it would also entail more costs for certification and multiple trade offs are to be made in terms of component selection and thermal management. Lastly, placement of the lens could be during the production phase, as well as, in the post-production phase. The first phase has three options in which the lens could be placed, which bring about multiple disadvantages, such as, higher costs due to more man hours, in addition to, higher costs for the need of multiple mould. The later phase includes the use of a method called ultrasonic welding. This type of fabrication would create a seamless joint between the lens and the VL, which would not only seal the electronics compartment, but it would also ensure that the lens can not come undone, preventing serious harm to the airway during intubation. Conclusion: In terms of material properties, both glass and pmma are suitable to act as a lens for the VL according to the context it is placed in. However, as glass lenses cost 590 times more than the pmma lenses, this would be the best choice to incorporate into the VL. From the three generated concept designs, the second design was the most desirable as it would not only generate a waterproof design, but it also has the ability to keep its modularity, for both future development as well as optional maintenance in the case that a part breaks down. Although the wireless design is feasible, it is advised to postpone this design. Regarding the insertion of the lens, the preferred choice would be to place it in combination with ultrasonic welding, to create a seamless and waterproof seal for the electronics compartment.