Validating Reusability: Assessing the Cleanability of the Vela Vacuum Extractor

Abstract

INTRODUCTION: The importance of reusable medical devices is increasingly evident due to their sustainability and accessibility advantages in high- and low- & middle-income countries. In response, LAYCO Medical Devices is developing a reusable vacuum extractor, vela®, as an alternative to the commonly used disposable vacuum extractor. This study aims to validate vela®’s reusability, focusing on reprocessing and explicitly on cleaning. The design of vela® is nearing completion; however, the device has not been manufactured in the final material. Ultimately, the plan is to produce vela® through injection molding of polyphenylsulfone. However, given the current stage of vela®, both in terms of time and cost, it is not advantageous to apply this production method now. Therefore, the research is divided into two parts: material validation and design validation. The material validation involves examining the suitability of polyphenylsulfone, the proposed final material, and identifying a suitable prototype material for testing the cleanability of the vela® design. For the design validation, the vela® design is examined to determine its effectiveness in cleaning within both high- and low- & middle-income countries, as different reprocessing methods are used in these settings.
METHODS: Clinical simulation tests were performed in the material and design validations to assess contamination at predefined hard-to-clean locations after cleaning. The locations were first soiled with Browne washer-disinfector soil, then cleaned and tested with the adenosine triphosphate and protein tests, each with predetermined thresholds. For material validation, an object made of polyphenylsulfone was selected. Through 3D printing, the polyphenylsulfone object was replicated in five potential prototyping materials to facilitate a comprehensive comparison. These six test objects were subjected to clinical simulation tests. Then, the test objects underwent in-depth material analysis to understand the material better and make a more reasoned selection for the prototype material. For the design validation, the design of vela® is printed in the material obtained through the material validation. These vela®’s undergo clinical simulation tests in both high- and low- & middle-income country settings. Given the manual nature of the low- & middle-income country cleaning procedure, additional layman’s tests are conducted to minimize user bias.
RESULTS: For the clinical simulation tests of the material validation, the results obtained from the polyphenylsulfone test object remained below the predetermined threshold. For the prototype material, only the test objects made of polycarbonate and tough 2000 resin withstood the cleaning procedure, and the tests stayed below the predetermined threshold value. Subsequently, the material analysis revealed that polyphenylsulfone and tough 2000 resin have the
least surface irregularities and absorb the least water. Therefore, the vela® prototype was printed in tough 2000 resin. For the clinical simulation tests of the design validation, contamination was observed at specific locations of vela® in
both test settings. In the high-income country setting, test results above the threshold value are observed in the space between the diaphragm. The results are more varied in the low- & middle-income country setting; hence, layman’s
tests were added to minimize user bias and obtain a more concrete result. Ultimately, test results above the threshold value are observed in the space between the diaphragm and the connection between the tube and handle.
CONCLUSION: For the material validation, polyphenylsulfone is identified as a suitable material for the final vela®. Tough 2000 resin is deemed appropriate as a prototype material to validate cleaning. For the design validation, it is concluded that design improvements are needed for two specific locations on the vela® to improve cleaning. The connection requires a redesign to facilitate easy disassembly. The diaphragm with stem is composed of silicone and hard plastic, and it is advisable to employ two-component injection molding to produce this part. When incorporating these suggestions into the design, it can be concluded that vela® can be safely reused in both high- and low-&middle-income countries, contributing to the sustainability and accessibility of medical devices.