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The operation of numerous drug-delivery, medical and therapeutic device systems often depends on a change in force. This change can either be instigated by the patient (i.e. manually) or by the device itself (i.e. automatically).
Force sensors can quantify changes in force and transmit this data to the clinician and/or patient for modifications. Certain insulin systems, for example, can assess blood glucose levels and generate regulated doses of insulin to patients with diabetes, while alternative force sensors can help administer the quantity of medication received by a patient. In the modern world, technology capturing and monitoring these alterations in force can thus streamline the functions of medical devices, rendering them “smarter” and more efficient in its delivery of therapy. Broadly, these “smart” medical devices can reduce the guesswork and maximize outcomes.
Force-sensing technology permits advanced monitoring of force changes and, when integrated within a medical device, enables that device to increase efficiency in its main function(s). The challenge posed by force sensors often derives in the selection process, due to the fact that devices vary in size, function, software requirements, indication, etc. This is where custom-designed force sensors make a difference. Custom-made sensors, especially in the medical device industry, might represent the solution for systems that typically depend on a one-size-fits-all approach.
Examples of Force Sensors in the Medical Industry
Functionality and flexibility are crucial features of choosing a force sensor, as is selecting a sensor that minimizes utilization burden to the end user. For medical devices, custom-designed sensors might provide the answer, as this option permits enhanced flexibility in the device's design. Although numerous force sensors are small and compact, custom-designed sensors permit more straightforward integration into devices, irrespective of their dimensions. Taking into account the diversity in the medical industry, custom-made force sensors are often crucial for many medical devices.
An upstream occlusion sensor, regularly utilized in peristaltic infusion pumps designed to pump IV fluids through infusion systems, is one example of a force sensor. A custom-made occlusion sensor identifies alterations in pressure in the tubing built into peristaltic infusion pumps. During routine functioning, fluid moves along the tubing, causing it to push outward and apply a force on the sensor. In the presence of occlusion, the tubing subsequently withdraws from the sensor, reducing the force triggering. This reduction usually suggests the use of an obstruction or warning in the fluid path.
A further example comprises strain gauge transducers for surgical table weight feedback, which thus ultimately provide precise patient positioning during surgery. To calculate position weight feedback during surgery, and to then enhance post-surgical outcomes, transducer class single-grid linear-pattern strain gauges are installed on plates.
Force sensors are also able to determine correct balance within the joint during orthopedic surgery. During functioning, force sensors can measure force and assist surgeons in making necessary adjustments in accordance with the given data. Foot rehabilitation can be a further area where force-sensing technology can support the healing process. The sensors can be integrated into biofeedback systems and function to augment gait.
Laparoscopic surgical instruments are an additional medical device area where custom-designed force sensors might be successfully applied. In sophisticated laparoscopic surgery in the abdomen, for instance, strain gauges can be implemented for force quantification. The gauges permit improvements in observing the working site as well as measurement of pressure on the trocar and entry site.
The Benefit of Custom-Made Force Sensors for Medical Devices
Due to their accuracy, engineers generally utilize either strain gauges or load cells in force sensors, including threaded rod load cell, rod end force, pancake force sensor, and high overload protected load cell. Touch sensors can be easily customized to conform to or around a device to quantify force changes. High-pressure micro-needle drug-delivery devices are a good example of embedded touch sensors. Force sensors can be custom-made to fit around the micro-needle, allowing a more thorough and complete application of the needle patch.
When designing force sensors, engineers must consider the usability challenges to patients posed by current devices and how a sensor might assist in the capture of force changes or force impacts. Moreover, engineers should work diligently during the prototype process to make sure that the force-sensing technology will not necessitate excess space or power to support the functionality of the device. The force sensor supplier must also be an ISO 13485-certified company with a documented history of designing sensors for the medical device industry.
HITEC Sensor Developments is an organization leading the way for the medical industry in custom-designed force sensors, producing a wide range of force sensors tailored specifically for devices across multiple indications.
References and Further Reading
- Force-Sensitive Resistors: Making Medical Devices Easier to Use | Medical Design Briefs. Available at: https://www.medicaldesignbriefs.com/component/content/article/mdb/features/28350#. (Accessed: 24 May 2019)
- Zhao, B. & Nelson, C.A. Sensorless Force Sensing for Minimally Invasive Surgery. J. Med. Device. 9, 0410121–04101214 (2015).
- Mensh B.D., Wisniewski N.A., Neil B.M., Burnett D.R. Susceptibility of Interstitial Continuous Glucose Monitor Performance to Sleeping Position. J. Diabetes. Sci. Technol. 7, 863–870 (2013).
- Ma, C. Z., Wong D.W., Lam W.K., Wan A.H., Lee W.C. Balance Improvement Effects of Biofeedback Systems with State-of-the-Art Wearable Sensors: A Systematic Review. Sensors (Basel). 16, 434 (2016).
This information has been sourced, reviewed and adapted from materials provided by HITEC Sensor Developments, Inc.
For more information on this source, please visit HITEC Sensor Developments, Inc.