Choosing the Best Pressure Sensors for Medical Applications

Pressure is a crucial physiological parameter in medical science, with accurate measurement being essential for both diagnostic precision and effective therapy across various liquid and gas environments.¹

Merit Sensor Systems, a pioneer in MEMS piezoresistive pressure sensing, offers top-notch solutions across multiple industries.² Their AP Series pressure sensors, in particular, are expertly crafted for use in pharmaceutical and medical applications.

This article looks at two setups of the AP Series pressure sensor:

1. AP-Series features polycarb or ferrule ports for direct media contact on the backside.
2. AP-Series with gel-port and dielectric gel for improved media biocompatibility.

The article also explores the use of these sensors in medical and pharmaceutical operations, including their integration with Merit Medical's Blue Diamond^™ Digital Inflation Device.

The AP-Series: Examining the Sensor’s Dual Configurations

Both variations of the AP-Series pressure sensor use a piezoresistive Wheatstone bridge and a chemically etched silicon diaphragm to deliver precise pressure measurements in static and dynamic situations.³

Each sensor, which can measure both liquids and gasses, is designed to be cost-effective while maintaining performance.

Image Credit: Merit Sensor

Key Features

• Wide Pressure Range: The AP-Series sensors cover several pressure ranges from 0 to 1000 psi (0 to 70 bar), accommodating a variety of medical and pharmaceutical applications, from vacuum aspiration applications to low-pressure blood pressure, up to high-pressure injection and pump control applications. ⁴
• High Accuracy: The sensors offer a trimmed output signal with minimal offset for easy amplification with an operational amplifier. This is achieved by calibrating the sensors using laser-trimmed resistors.⁴
• Robustness: These sensors are reliable even in challenging environments and are designed to withstand high burst pressures. Their compact geometry and durability make them suitable for integration into a multitude of medical devices. The design is suitable for single-use disposable applications as well as long-term applications.
• Sterilization Compatibility: These sensors are compatible with sterilization processes, including ETO, Gamma-ray, and autoclave, and must meet the rigorous standards required in medical applications.
• Easy Integration: With options for flexible or cable interfaces, the AP-Series sensors can be seamlessly integrated into existing systems.
• High Resolution and Frequency: These sensors deliver a pure analog signal to allow exceptional performance in high-resolution and high-frequency applications.³
• Reliable Through Backside: Both configurations ensure that the active side of the sensing element (wirebonds and conductor traces) are shielded from direct contact with the media, enhancing the sensor’s longevity and reliability.

Image Credit: Merit Sensor

Applications

The AP-Series sensors, which have a polycarb and ferrule port as well as direct media contact on the backside, are suited for measuring liquid and gas pressure and flow in medical and pharmaceutical equipment. Typical applications include:

• Mixing Machines: Guaranteeing accurate pressure control during the mixing of pharmaceuticals.
• Analysis Machines: Precise pressure monitoring in laboratory equipment for fluid analysis.
• Fluid Treatment and Processing: This is used in systems that require precise pressure regulation to ensure the integrity of the fluid being processed.
• Aseptic Liquid Processing: Key when it comes to maintaining sterility and preventing contamination during the production of pharmaceuticals.

The AP-Series pressure sensors feature enhanced media compatibility with gel-port and dielectric gel, reducing wetted materials and making them ideal for challenging environments in pharmaceutical and medical applications, including:

• Bio-Decontamination Equipment: Monitoring pressure in systems that are created to sterilize equipment and facilities.
• Bioreactor Monitoring, Chromatography, and Flow Filtration: Ensuring reliable pressure measurements in critical biocompatibility processes.
• Laboratory Equipment: Providing precise pressure data in equipment used for sophisticated chemical analyses and experiments.

Image Credit: Merit Sensor

Integration with the Blue Diamond^™ Digital Inflation Device

Merit Medical's Blue Diamond^™ Digital Inflation Device and Fluid Dispensing Syringe uses AP-Series pressure sensors. This device is intended for inflating and deflating balloon angioplasty catheters and other interventional devices.

It can also be used to precisely quantify the pressure and duration of inflation while delivering fluids into the body and monitoring pressure levels.⁵

Features of the Blue Diamond^™ Digital Inflation Device

• Integral Pressure Transducer: This device is equipped with AP-Series sensors, which are crucial for the safe and effective execution of angioplasty procedures. These sensors provide precise pressure measurements.⁵ 
• Microcomputer and Back-Lit LCD: These features enable the precise control and simple monitoring of the inflation process in low- and no-light conditions.^5,6
• Threaded Plunger Assembly and High-Pressure Extension Tube: These components, when combined with Merit Sensor's durable pressure sensors, guarantee that the device can generate and monitor positive and negative pressures within a range of -0.4 to +30 ATM/BAR (-6 to 441 psi).⁵
• Data Recording and Recall: This feature of the syringe electronics enables users to record and recollect prior inflation information, rendering it an ideal choice for procedure data tracking.⁷ 

Image Credit: Merit Sensor

Merit Sensor Systems: Pharmaceutical and Medical Solutions You Can Trust

Merit Sensor Systems' AP Series pressure sensors are the preferred choice for a wide range of pharmaceutical and medical applications.

The two configurations—gel-port with direct backside media contact and gel-port with dielectric gel—provide greater versatility and media compatibility while maintaining precision, robustness, and cost-effectiveness.

In addition, its adherence to medical standards and incorporation into critical devices, such as Merit Medical's Blue Diamond^™ Digital Inflation Device, demonstrate its dependability and adaptability in challenging medical settings. To find out more about how these devices can be integrated into your workflow, contact a member of the Merit Sensor System’s team today.

References

1. Casey, V., et al. (2011). Pressure Measurement at Biomedical Interfaces. Applied Biomedical Engineering. doi.org/10.5772/21855
2. Merit Sensors. [Online] Applications. Available at: https://meritsensor.com/ (Accessed on 26 May 2024).
3. Merit Sensor. Data Sheet: AP Series. Available at: https://meritsensor.com/assets/documents/pdf/AP-series.pdf (Accessed on 26 May 2024).
4. Merit Sensor. [Online] AP Series. Available at: https://meritsensor.com/products/AP-Series/ (Accessed on 26 May 2024).
5. Merit Medical. Blue Diamond^™ Digital Inflation Device. Available at: https://cloud.merit.com/catalog/IFUs/407737001.pdf (Accessed on 02 July 2024).
6. Merit Medical. [Online] Blue Diamond^™ Digital Inflation Device. Available at: https://www.merit.com/product/blue-diamond-inflation-device/#documents_education (Accessed on 2 July 2024).
7. Merit Medical. A Global Leader in Inflation. Available at: https://cloud.merit.com/catalog/Brochures/400899001.pdf (Accessed on 2 July 2024).

This information has been sourced, reviewed and adapted from materials provided by Merit Sensor.

For more information on this source, please visit Merit Sensor.