A.J. Loeve
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6 records found
1
This study explores the impact of different bicycle saddle designs on saddle pressure distribution and comfort in female cyclists suffering from medical conditions affecting the groin area, including Lichen Sclerosus, Lichen Planus, and Vulvar Carcinoma. These conditions can cause discomfort and pain during cycling, leading to a decrease in physical activity and quality of life. The research involved a comparison of four distinct saddle designs, each aimed at reducing pressure in specific areas through partial cutouts or surface depressions. Participants were divided into a case group, comprising 23 women with the aforementioned medical conditions, and a control group of 50 women with no such conditions. Pressure measurements were collected using a stationary bicycle and a pressure mapping saddle cover containing 64 sensors. Additionally, participants completed questionnaires to evaluate perceived comfort and symptom severity. The quality of life (QoL) score was significantly lower in the case group (0.83 ± 0.09) compared to the control group (0.96 ± 0.09, p < 0.001). No significant differences were found between the case and control group in terms of cycling habits. Complaints during cycling were reported by 100% of the participants in the case group and only 8% of the participants in the control group. Pain and numbness were the most reported symptoms for cycling at home. The results indicated significant differences in loaded weight per saddle between the case and control groups (p = 0.001, p = 0.010, p = 0.003 & p = 0.013). In the case group, participants experienced higher pressure. Saddle 2 was favored by 44% of the case group participants for home testing. These findings underscore the need for specialized saddle designs to improve cycling comfort and potentially alleviate pain for women with medical conditions in the groin area.
...
This study explores the impact of different bicycle saddle designs on saddle pressure distribution and comfort in female cyclists suffering from medical conditions affecting the groin area, including Lichen Sclerosus, Lichen Planus, and Vulvar Carcinoma. These conditions can cause discomfort and pain during cycling, leading to a decrease in physical activity and quality of life. The research involved a comparison of four distinct saddle designs, each aimed at reducing pressure in specific areas through partial cutouts or surface depressions. Participants were divided into a case group, comprising 23 women with the aforementioned medical conditions, and a control group of 50 women with no such conditions. Pressure measurements were collected using a stationary bicycle and a pressure mapping saddle cover containing 64 sensors. Additionally, participants completed questionnaires to evaluate perceived comfort and symptom severity. The quality of life (QoL) score was significantly lower in the case group (0.83 ± 0.09) compared to the control group (0.96 ± 0.09, p < 0.001). No significant differences were found between the case and control group in terms of cycling habits. Complaints during cycling were reported by 100% of the participants in the case group and only 8% of the participants in the control group. Pain and numbness were the most reported symptoms for cycling at home. The results indicated significant differences in loaded weight per saddle between the case and control groups (p = 0.001, p = 0.010, p = 0.003 & p = 0.013). In the case group, participants experienced higher pressure. Saddle 2 was favored by 44% of the case group participants for home testing. These findings underscore the need for specialized saddle designs to improve cycling comfort and potentially alleviate pain for women with medical conditions in the groin area.
This thesis proposes a method of detecting autonomic neuropathy in low-income countries using an infrared camera. Access to healthcare is often limited in low-income countries delaying the detection of neuropathy. If neuropathy can be detected in the earliest stage, often the autonomic state, damage to motor and sensory nerves can be prevented. To develop the method for detecting autonomic neuropathy, first the autonomic system was researched, followed by looking into the effects of neuropathy on the autonomic system to discover what physical properties might be measured with the detection device.
Four affected physical properties were determined through literature research: blood flow, blood pressure, skin resistance, and skin temperature. Of these properties, skin temperature was found to be the most promising based on a literature study, as it seemed to be both easily measurable and relatively independent of other bodily functions. Then the constraints of healthcare in low-income countries were examined and devices that work within these constraints were identified. Of these, the infrared camera showed the most promise, because of its ease of use and cost to accuracy ratio.
A single-subject study was performed to test the restorative capacity of the autonomous system by deliberately changing the temperature of the hand with a heating and cooling agent. Four locations were used on both hands, and both palmar and dorsal side of the hand, using different doses of the agents. The temperature change of the skin was measured using an InfraRed (IR) camera.
A large variation in results was found, but the results did show some evidence for structural differences in the temperature normalization between the affected and unaffected hand. The palmar side shows a stronger reaction than the dorsal side. The cooling agent seems to be more effective, but there are some caveats attached to its use. An interesting observation is that the most noticeable difference between left and right was measured in an area of low circulation. This gives some indication that this area has the most difficulty with returning to the neutral state.
Conclusion: This research shows that skin temperature variation as a result of applying heating or cooling agents to the skin can be measured using an infrared camera, suggesting that minor variations in skin temperature as a result of neuropathy can also be measured, further research with more test subjects should be done. ...
Four affected physical properties were determined through literature research: blood flow, blood pressure, skin resistance, and skin temperature. Of these properties, skin temperature was found to be the most promising based on a literature study, as it seemed to be both easily measurable and relatively independent of other bodily functions. Then the constraints of healthcare in low-income countries were examined and devices that work within these constraints were identified. Of these, the infrared camera showed the most promise, because of its ease of use and cost to accuracy ratio.
A single-subject study was performed to test the restorative capacity of the autonomous system by deliberately changing the temperature of the hand with a heating and cooling agent. Four locations were used on both hands, and both palmar and dorsal side of the hand, using different doses of the agents. The temperature change of the skin was measured using an InfraRed (IR) camera.
A large variation in results was found, but the results did show some evidence for structural differences in the temperature normalization between the affected and unaffected hand. The palmar side shows a stronger reaction than the dorsal side. The cooling agent seems to be more effective, but there are some caveats attached to its use. An interesting observation is that the most noticeable difference between left and right was measured in an area of low circulation. This gives some indication that this area has the most difficulty with returning to the neutral state.
Conclusion: This research shows that skin temperature variation as a result of applying heating or cooling agents to the skin can be measured using an infrared camera, suggesting that minor variations in skin temperature as a result of neuropathy can also be measured, further research with more test subjects should be done. ...
This thesis proposes a method of detecting autonomic neuropathy in low-income countries using an infrared camera. Access to healthcare is often limited in low-income countries delaying the detection of neuropathy. If neuropathy can be detected in the earliest stage, often the autonomic state, damage to motor and sensory nerves can be prevented. To develop the method for detecting autonomic neuropathy, first the autonomic system was researched, followed by looking into the effects of neuropathy on the autonomic system to discover what physical properties might be measured with the detection device.
Four affected physical properties were determined through literature research: blood flow, blood pressure, skin resistance, and skin temperature. Of these properties, skin temperature was found to be the most promising based on a literature study, as it seemed to be both easily measurable and relatively independent of other bodily functions. Then the constraints of healthcare in low-income countries were examined and devices that work within these constraints were identified. Of these, the infrared camera showed the most promise, because of its ease of use and cost to accuracy ratio.
A single-subject study was performed to test the restorative capacity of the autonomous system by deliberately changing the temperature of the hand with a heating and cooling agent. Four locations were used on both hands, and both palmar and dorsal side of the hand, using different doses of the agents. The temperature change of the skin was measured using an InfraRed (IR) camera.
A large variation in results was found, but the results did show some evidence for structural differences in the temperature normalization between the affected and unaffected hand. The palmar side shows a stronger reaction than the dorsal side. The cooling agent seems to be more effective, but there are some caveats attached to its use. An interesting observation is that the most noticeable difference between left and right was measured in an area of low circulation. This gives some indication that this area has the most difficulty with returning to the neutral state.
Conclusion: This research shows that skin temperature variation as a result of applying heating or cooling agents to the skin can be measured using an infrared camera, suggesting that minor variations in skin temperature as a result of neuropathy can also be measured, further research with more test subjects should be done.
Four affected physical properties were determined through literature research: blood flow, blood pressure, skin resistance, and skin temperature. Of these properties, skin temperature was found to be the most promising based on a literature study, as it seemed to be both easily measurable and relatively independent of other bodily functions. Then the constraints of healthcare in low-income countries were examined and devices that work within these constraints were identified. Of these, the infrared camera showed the most promise, because of its ease of use and cost to accuracy ratio.
A single-subject study was performed to test the restorative capacity of the autonomous system by deliberately changing the temperature of the hand with a heating and cooling agent. Four locations were used on both hands, and both palmar and dorsal side of the hand, using different doses of the agents. The temperature change of the skin was measured using an InfraRed (IR) camera.
A large variation in results was found, but the results did show some evidence for structural differences in the temperature normalization between the affected and unaffected hand. The palmar side shows a stronger reaction than the dorsal side. The cooling agent seems to be more effective, but there are some caveats attached to its use. An interesting observation is that the most noticeable difference between left and right was measured in an area of low circulation. This gives some indication that this area has the most difficulty with returning to the neutral state.
Conclusion: This research shows that skin temperature variation as a result of applying heating or cooling agents to the skin can be measured using an infrared camera, suggesting that minor variations in skin temperature as a result of neuropathy can also be measured, further research with more test subjects should be done.
Development of Sharps Waste Device for Sustainable Healthcare Waste Management in Nepal
Design and Manufacturing Considerations
The project's purpose was to investigate the development of a medical sharps waste device appropriate for use and manufacture in Nepal. Medical sharps waste management in Nepal is still somewhat dangerous, despite the physical and environmental dangers.
After considering several design directions, it was determined to create a mechanism capable of mechanically pulling the needle tube out of the hub. A device like this will render needles unusable while simultaneously opening up possibilities for the recycling of the materials of needle waste. Additionally a device that mechanically separates the materials of needles does not currently exist.
Tensile tests were performed with various needle sizes and temperatures to better investigate this. There were no statistically significant differences between temperatures, although the results from 16 G needles differed significantly from the results from 20 G and 23 G needles. It was discovered that the device's minimum pulling force should be 500 N; this, along with information taken from several set standards and previous projects on needle devices, was then included into a set of requirements for the device.
After exploring several clamping, pulling, and combined mechanisms, a roller mechanism was chosen for the device. A functional prototype capable of extracting a needle tube from its hub was created. This prototype was then tested, and various experiments were carried out to try to enhance the design because needle tubes were still slipping in between the rollers on occasion, and some needle tubes broke off.
Adding other structures or a different material like rubber on the rollers did not result in better performance, and a knurling pattern worked best for creating grip on the needle tube. Adding a ridge did not improve the performance, however removing some material from both sides of the gap in Roller A did enhance performance temporarily. Making the rollers out of stainless steel 431 rather than 316 did not increase their performance; however, stainless steel 431 with a heat treatment did improve the performance and showed consistent test results. This final prototype, including the rollers made out of stainless steel 431 with a heat treatment was then used to do final verification and validation.
20 G needles could be pulled with the device consistently at a needle length of 33.8 mm, both wet and dry. 27 G needles however kept breaking off, both wet and dry. A design choice should be made here about if the device should be aimed at a smaller range of needles or a redesign should be made where different spring forces could be applied. The device showed not springback and no parts became trapped in the mechanism.
It was impossible to insert needles of various diameters at greater angles from the vertical of the aperture and 16 G needles did not fit into the device at all. A redesign is needed for this.
The average activation force of the device was 14.72 N and the distance from the hand holding the needle to the hand operating the device did not exceed 50 mm.
The cycle time per needle was still too long for the device. Further research is required to improve these parameters. The prototype did meet the weight and size requirements. The device did not have a sharps box attached to it, this should be added in a redesign.
If the rollers of the device are to be constructed of stainless steel 431, they should be made in India, since stainless steel 431 was not available in Nepal. The case, cubes, pushing plate, socket, spring axis, and lever may all be made in Nepal. Standard components, such as springs and bearings, may be obtained in India. However still choices and more research is needed in the area of where exactly the product should be produced and assembled.
More research is needed to determine how the metal components of needles may be recycled and how a device like this would work with different types of needles. Also researching if applying force to both rollers and a redesign either with a different spring of multiple spring forces should still be done.
More testing is needed to determine the pulling force and how many cycles the device can sustain. As well as a drop test, a tipping test on an angular surface and users tests.
Lastly research into how to incorporate a redesign where the syringe is also rendered unusable is needed, since this study only focused on making the needle part unusable by separating the materials. ...
After considering several design directions, it was determined to create a mechanism capable of mechanically pulling the needle tube out of the hub. A device like this will render needles unusable while simultaneously opening up possibilities for the recycling of the materials of needle waste. Additionally a device that mechanically separates the materials of needles does not currently exist.
Tensile tests were performed with various needle sizes and temperatures to better investigate this. There were no statistically significant differences between temperatures, although the results from 16 G needles differed significantly from the results from 20 G and 23 G needles. It was discovered that the device's minimum pulling force should be 500 N; this, along with information taken from several set standards and previous projects on needle devices, was then included into a set of requirements for the device.
After exploring several clamping, pulling, and combined mechanisms, a roller mechanism was chosen for the device. A functional prototype capable of extracting a needle tube from its hub was created. This prototype was then tested, and various experiments were carried out to try to enhance the design because needle tubes were still slipping in between the rollers on occasion, and some needle tubes broke off.
Adding other structures or a different material like rubber on the rollers did not result in better performance, and a knurling pattern worked best for creating grip on the needle tube. Adding a ridge did not improve the performance, however removing some material from both sides of the gap in Roller A did enhance performance temporarily. Making the rollers out of stainless steel 431 rather than 316 did not increase their performance; however, stainless steel 431 with a heat treatment did improve the performance and showed consistent test results. This final prototype, including the rollers made out of stainless steel 431 with a heat treatment was then used to do final verification and validation.
20 G needles could be pulled with the device consistently at a needle length of 33.8 mm, both wet and dry. 27 G needles however kept breaking off, both wet and dry. A design choice should be made here about if the device should be aimed at a smaller range of needles or a redesign should be made where different spring forces could be applied. The device showed not springback and no parts became trapped in the mechanism.
It was impossible to insert needles of various diameters at greater angles from the vertical of the aperture and 16 G needles did not fit into the device at all. A redesign is needed for this.
The average activation force of the device was 14.72 N and the distance from the hand holding the needle to the hand operating the device did not exceed 50 mm.
The cycle time per needle was still too long for the device. Further research is required to improve these parameters. The prototype did meet the weight and size requirements. The device did not have a sharps box attached to it, this should be added in a redesign.
If the rollers of the device are to be constructed of stainless steel 431, they should be made in India, since stainless steel 431 was not available in Nepal. The case, cubes, pushing plate, socket, spring axis, and lever may all be made in Nepal. Standard components, such as springs and bearings, may be obtained in India. However still choices and more research is needed in the area of where exactly the product should be produced and assembled.
More research is needed to determine how the metal components of needles may be recycled and how a device like this would work with different types of needles. Also researching if applying force to both rollers and a redesign either with a different spring of multiple spring forces should still be done.
More testing is needed to determine the pulling force and how many cycles the device can sustain. As well as a drop test, a tipping test on an angular surface and users tests.
Lastly research into how to incorporate a redesign where the syringe is also rendered unusable is needed, since this study only focused on making the needle part unusable by separating the materials. ...
The project's purpose was to investigate the development of a medical sharps waste device appropriate for use and manufacture in Nepal. Medical sharps waste management in Nepal is still somewhat dangerous, despite the physical and environmental dangers.
After considering several design directions, it was determined to create a mechanism capable of mechanically pulling the needle tube out of the hub. A device like this will render needles unusable while simultaneously opening up possibilities for the recycling of the materials of needle waste. Additionally a device that mechanically separates the materials of needles does not currently exist.
Tensile tests were performed with various needle sizes and temperatures to better investigate this. There were no statistically significant differences between temperatures, although the results from 16 G needles differed significantly from the results from 20 G and 23 G needles. It was discovered that the device's minimum pulling force should be 500 N; this, along with information taken from several set standards and previous projects on needle devices, was then included into a set of requirements for the device.
After exploring several clamping, pulling, and combined mechanisms, a roller mechanism was chosen for the device. A functional prototype capable of extracting a needle tube from its hub was created. This prototype was then tested, and various experiments were carried out to try to enhance the design because needle tubes were still slipping in between the rollers on occasion, and some needle tubes broke off.
Adding other structures or a different material like rubber on the rollers did not result in better performance, and a knurling pattern worked best for creating grip on the needle tube. Adding a ridge did not improve the performance, however removing some material from both sides of the gap in Roller A did enhance performance temporarily. Making the rollers out of stainless steel 431 rather than 316 did not increase their performance; however, stainless steel 431 with a heat treatment did improve the performance and showed consistent test results. This final prototype, including the rollers made out of stainless steel 431 with a heat treatment was then used to do final verification and validation.
20 G needles could be pulled with the device consistently at a needle length of 33.8 mm, both wet and dry. 27 G needles however kept breaking off, both wet and dry. A design choice should be made here about if the device should be aimed at a smaller range of needles or a redesign should be made where different spring forces could be applied. The device showed not springback and no parts became trapped in the mechanism.
It was impossible to insert needles of various diameters at greater angles from the vertical of the aperture and 16 G needles did not fit into the device at all. A redesign is needed for this.
The average activation force of the device was 14.72 N and the distance from the hand holding the needle to the hand operating the device did not exceed 50 mm.
The cycle time per needle was still too long for the device. Further research is required to improve these parameters. The prototype did meet the weight and size requirements. The device did not have a sharps box attached to it, this should be added in a redesign.
If the rollers of the device are to be constructed of stainless steel 431, they should be made in India, since stainless steel 431 was not available in Nepal. The case, cubes, pushing plate, socket, spring axis, and lever may all be made in Nepal. Standard components, such as springs and bearings, may be obtained in India. However still choices and more research is needed in the area of where exactly the product should be produced and assembled.
More research is needed to determine how the metal components of needles may be recycled and how a device like this would work with different types of needles. Also researching if applying force to both rollers and a redesign either with a different spring of multiple spring forces should still be done.
More testing is needed to determine the pulling force and how many cycles the device can sustain. As well as a drop test, a tipping test on an angular surface and users tests.
Lastly research into how to incorporate a redesign where the syringe is also rendered unusable is needed, since this study only focused on making the needle part unusable by separating the materials.
After considering several design directions, it was determined to create a mechanism capable of mechanically pulling the needle tube out of the hub. A device like this will render needles unusable while simultaneously opening up possibilities for the recycling of the materials of needle waste. Additionally a device that mechanically separates the materials of needles does not currently exist.
Tensile tests were performed with various needle sizes and temperatures to better investigate this. There were no statistically significant differences between temperatures, although the results from 16 G needles differed significantly from the results from 20 G and 23 G needles. It was discovered that the device's minimum pulling force should be 500 N; this, along with information taken from several set standards and previous projects on needle devices, was then included into a set of requirements for the device.
After exploring several clamping, pulling, and combined mechanisms, a roller mechanism was chosen for the device. A functional prototype capable of extracting a needle tube from its hub was created. This prototype was then tested, and various experiments were carried out to try to enhance the design because needle tubes were still slipping in between the rollers on occasion, and some needle tubes broke off.
Adding other structures or a different material like rubber on the rollers did not result in better performance, and a knurling pattern worked best for creating grip on the needle tube. Adding a ridge did not improve the performance, however removing some material from both sides of the gap in Roller A did enhance performance temporarily. Making the rollers out of stainless steel 431 rather than 316 did not increase their performance; however, stainless steel 431 with a heat treatment did improve the performance and showed consistent test results. This final prototype, including the rollers made out of stainless steel 431 with a heat treatment was then used to do final verification and validation.
20 G needles could be pulled with the device consistently at a needle length of 33.8 mm, both wet and dry. 27 G needles however kept breaking off, both wet and dry. A design choice should be made here about if the device should be aimed at a smaller range of needles or a redesign should be made where different spring forces could be applied. The device showed not springback and no parts became trapped in the mechanism.
It was impossible to insert needles of various diameters at greater angles from the vertical of the aperture and 16 G needles did not fit into the device at all. A redesign is needed for this.
The average activation force of the device was 14.72 N and the distance from the hand holding the needle to the hand operating the device did not exceed 50 mm.
The cycle time per needle was still too long for the device. Further research is required to improve these parameters. The prototype did meet the weight and size requirements. The device did not have a sharps box attached to it, this should be added in a redesign.
If the rollers of the device are to be constructed of stainless steel 431, they should be made in India, since stainless steel 431 was not available in Nepal. The case, cubes, pushing plate, socket, spring axis, and lever may all be made in Nepal. Standard components, such as springs and bearings, may be obtained in India. However still choices and more research is needed in the area of where exactly the product should be produced and assembled.
More research is needed to determine how the metal components of needles may be recycled and how a device like this would work with different types of needles. Also researching if applying force to both rollers and a redesign either with a different spring of multiple spring forces should still be done.
More testing is needed to determine the pulling force and how many cycles the device can sustain. As well as a drop test, a tipping test on an angular surface and users tests.
Lastly research into how to incorporate a redesign where the syringe is also rendered unusable is needed, since this study only focused on making the needle part unusable by separating the materials.
This project explores the context of laboratory technicians at the NFI and CSIs with the police, and their experience using dry wipes and disinfectant dispensers at their work. It also delves into designing a new dispenser for them, which is the project aim, with a focus on prototyping and validating designs.
...
This project explores the context of laboratory technicians at the NFI and CSIs with the police, and their experience using dry wipes and disinfectant dispensers at their work. It also delves into designing a new dispenser for them, which is the project aim, with a focus on prototyping and validating designs.
A Variable Bending Stiffness Instrument: The AlKingScope
A Proof of Concept Prototype
When treating a Chronic Total Occlusion (CTO) via Percutaneous Coronary Intervention (PCI), a guidewire first needs to be passed through or around the occlusion, a task requiring considerable skill and clinician experience. Proper backup support for the guidewire being used by the clinician is a prerequisite to prevent buckling or uncontrolled movement. Three different concepts that can vary their stiffness were generated, prototyped and evaluated against each other. Finally, a mechanism was designed that can vary its stiffness drastically by radially jamming wires together between a braided sheath and a radially rigid core that is also flexible in bending. Friction between the wires and the steerable segment generates the stiff configuration. If the braided sheath is released the wires can move along each other and the mechanism is flexible. The variable stiffness ability was tested by clamping the mechanism into a frame while applying a load to the distal tip. This resulted in a force-displacement curve that was 20 times stiffer in the stiff state than in the flexible state. The use of a braided sheath in a Variable Stiffness Mechanism (VSM) is an effective and
simple way to obtain variable stiffness. The proposed design is a step forward in the developing process for VSM for cardiovascular applications. ...
simple way to obtain variable stiffness. The proposed design is a step forward in the developing process for VSM for cardiovascular applications. ...
When treating a Chronic Total Occlusion (CTO) via Percutaneous Coronary Intervention (PCI), a guidewire first needs to be passed through or around the occlusion, a task requiring considerable skill and clinician experience. Proper backup support for the guidewire being used by the clinician is a prerequisite to prevent buckling or uncontrolled movement. Three different concepts that can vary their stiffness were generated, prototyped and evaluated against each other. Finally, a mechanism was designed that can vary its stiffness drastically by radially jamming wires together between a braided sheath and a radially rigid core that is also flexible in bending. Friction between the wires and the steerable segment generates the stiff configuration. If the braided sheath is released the wires can move along each other and the mechanism is flexible. The variable stiffness ability was tested by clamping the mechanism into a frame while applying a load to the distal tip. This resulted in a force-displacement curve that was 20 times stiffer in the stiff state than in the flexible state. The use of a braided sheath in a Variable Stiffness Mechanism (VSM) is an effective and
simple way to obtain variable stiffness. The proposed design is a step forward in the developing process for VSM for cardiovascular applications.
simple way to obtain variable stiffness. The proposed design is a step forward in the developing process for VSM for cardiovascular applications.
Rinsing of complex conduit geometries in implanted insulin infusion devices
Effectiveness of removing insulin precipitates from conduits
Implanted intra-peritoneal insulin infusion (‘i4’) devices administer insulin into the peritoneum of diabetic patients with extreme blood glucose swings, that are highly difficult to control. The flushing procedures of i4 devices to clear obstructions from its conduits caused by insulin degradation are not always fully effective. The goal of this research was to investigate how the flushing effectiveness can be increased by adapting conduit geometries and adapting the flush flow rate. It was hypothesized that flushing of conduits with complex geometries (featuring a.o. widened sections, or parallel flow paths) would be less effective than simple geometries, and that a higher flush flow rate would increase flushing effectiveness. An ex vivo laboratory experimental setup was created by producing polymethyl methacrylate (PMMA) test conduits of differing geometries that model the in vivo implanted intra-peritoneal insulin infusion (i4) device’s conduits, but are transparent to allow optical inspection. These test conduits were filled with acidified insulin, and precipitation thereof was artificially induced by heat incubation of the filled conduits, as a model for obstructed i4-device conduits. Experimental flushing procedures using sodium hydroxide (NaOH) as a flush liquid were performed on these test conduits at 2 different flush flow rates: 1.5mL/min, and at 20mL/min. After the flushing, the effectiveness of the procedure to clear the conduit of precipitates was evaluated by microscopically analysing the quantity of residual precipitates, and measuring Total Organic Carbon (TOC) of a liquid sample taken from the post-flushing conduit. All conduits with more complex geometries than straight tubes showed lower effectiveness of cleaning by flushing. The high flow rate showed an averaged 19% higher effectiveness of the flushing. In the sections of the conduits featuring widening, flushing often resulted in a narrow path being effectively cleaned, but significant regions of the conduit showed presence of residual precipitates. This research provides insight into the negative influence of complex geometries on effectiveness of flushing, and the positive influence of increased flush flow rate to improve effectiveness. Experimental repetition in this research is low, and the experimental methods were prone to much influence of material or measurement disturbances. This research merits elaboration and improvement of materials and methods to more precisely investigate the proposed relations. Outcomes suggest that future i4-devices should be designed to avoid complex conduit geometries as much as possible, and to be flushed with significantly higher flush flow rates than currently clinically applied.
...
Implanted intra-peritoneal insulin infusion (‘i4’) devices administer insulin into the peritoneum of diabetic patients with extreme blood glucose swings, that are highly difficult to control. The flushing procedures of i4 devices to clear obstructions from its conduits caused by insulin degradation are not always fully effective. The goal of this research was to investigate how the flushing effectiveness can be increased by adapting conduit geometries and adapting the flush flow rate. It was hypothesized that flushing of conduits with complex geometries (featuring a.o. widened sections, or parallel flow paths) would be less effective than simple geometries, and that a higher flush flow rate would increase flushing effectiveness. An ex vivo laboratory experimental setup was created by producing polymethyl methacrylate (PMMA) test conduits of differing geometries that model the in vivo implanted intra-peritoneal insulin infusion (i4) device’s conduits, but are transparent to allow optical inspection. These test conduits were filled with acidified insulin, and precipitation thereof was artificially induced by heat incubation of the filled conduits, as a model for obstructed i4-device conduits. Experimental flushing procedures using sodium hydroxide (NaOH) as a flush liquid were performed on these test conduits at 2 different flush flow rates: 1.5mL/min, and at 20mL/min. After the flushing, the effectiveness of the procedure to clear the conduit of precipitates was evaluated by microscopically analysing the quantity of residual precipitates, and measuring Total Organic Carbon (TOC) of a liquid sample taken from the post-flushing conduit. All conduits with more complex geometries than straight tubes showed lower effectiveness of cleaning by flushing. The high flow rate showed an averaged 19% higher effectiveness of the flushing. In the sections of the conduits featuring widening, flushing often resulted in a narrow path being effectively cleaned, but significant regions of the conduit showed presence of residual precipitates. This research provides insight into the negative influence of complex geometries on effectiveness of flushing, and the positive influence of increased flush flow rate to improve effectiveness. Experimental repetition in this research is low, and the experimental methods were prone to much influence of material or measurement disturbances. This research merits elaboration and improvement of materials and methods to more precisely investigate the proposed relations. Outcomes suggest that future i4-devices should be designed to avoid complex conduit geometries as much as possible, and to be flushed with significantly higher flush flow rates than currently clinically applied.