Bench Talk

(Source: Jaromir Chalabala/Shutterstock.com)

Treating health issues and medical complaints used to take place almost exclusively within a clinical environment, but a seismic shift has occurred in the past decade. Greater focus is now being placed on monitoring and treating patients at home. Several drivers for this include:

• Relieving strain on already stretched healthcare resources.
• Enabling patients with chronic conditions to have a better quality of life without the inconvenience of regularly traveling to a hospital for treatment or check-ups.
• Avoiding hospitals to safeguard patients by reducing their risk of contracting diseases like MRSA and COVID-19.

Increasing reliance on home-based healthcare activities—such as monitoring blood glucose levels and oxygen saturation, as well as more complicated procedures like dialysis—sets new challenges for medical equipment manufacturers. These challenges include:

• Patients themselves, not trained staff, use portable equipment, which carries the potential for incorrect use.
• Units should not take up too much space in the home or be difficult for patients to carry.
• Portable medical equipment must also exhibit high degrees of mechanical robustness because they are prone to damage in emergencies.
• Connectors and cabling might be located outside of the enclosures of the equipment and, if this is the case, they are more exposed to rough treatment than internally located components.

Therefore, the interconnect design needs careful consideration to ensure its operational reliability because failure could have life-threatening consequences. Here, we discuss the specifications connectors must have to meet today’s portable medical equipment design requirements.

The need for equipment to be compact and portable places acute size and weight limitations on the design, and the chosen components should be optimized accordingly. To save space and reduce weight, it is advisable to specify connectors that can deliver a combination of both power and data signals. Appropriately sized dedicated contact pins will be required for each of these purposes to avoid heating effects and signal integrity issues. In addition, an effective insulation material needs to be incorporated into the connectors to prevent flashover because this could impact the equipment’s data acquisition functions.

Portable equipment used by first responders needs to be robust enough to cope with harsh environments. Therefore, the components must be resilient to extreme temperature, high humidity levels, and water ingress. Also, while working under pressure responding to life or death situations, first responders make and break connections quickly, and the connectors must be able to cope with mismating errors.

Patients using equipment themselves at home or being monitored by family are usually less familiar with how to operate medical devices properly, so the enormous potential for mismating connectors exists. Selecting connectors with polarization and shrouding can help to eliminate this from happening. Interconnect retention is another important factor, and including some form of locking mechanism can help with this. Under certain circumstances, backpotting might need to be applied to the connectors to give strain relief to the associated cabling.

Electromagnetic interference (EMI) concerns must be addressed for compliance approval of medical equipment. Internal shielding is necessary to stop interference with other electronics within the system. Additionally, external interference must not impinge on data signals passing through interconnects. Connectors can be fitted with metal backshells, and cables can feature metal braiding as an EMI-shielding solution. Some mechanisms can be put in place to mitigate the threat posed by electrostatic discharge (ESD).

Harwin’s high-reliability, dependable connector solutions are featured in equipment from many leading manufacturers in the medical sector. The company’s Gecko (1.25mm pitch) and Datamate (2mm pitch) (Figure 1) connector series support over 1000 and 500 mating cycles, respectively. 4-finger Beryllium Copper construction of their contacts means that interconnect integrity is always maintained—with electrical connection via at least one mating surface—even when subjected to heavy shocks and ongoing vibration. Advanced, quick-action locking mechanisms mean that equipment is ready-to-use quickly, and its long-term operation is assured.

Figure 1: Harwin Datamate J-Tek double-ended female cable assemblies offer high reliability in low-profile designs that combine the simplicity of a complete plug-and-play solution with the reduced vertical space required. (Source: Mouser Electronics)

Harwin has an extensive portfolio of connectors that are highly suited for medical applications with a proven track record, and these are supported by a wide variety of off-the-shelf cable and FPC assembly options (Figure 2).

Figure 2: Harwin’s flexible printed circuits (FPC), low-profile cables combine the go-anywhere routing of cables with the reduced vertical space offered by your choice of either the Datamate J-Tek 1mm pitch or the Gecko 0.5mm pitch in standard 10-contact assemblies in single- and double-ended designs. (Source: Harwin)

When used in portable medical equipment, connectors need to deliver both strong performance parameters and enduring reliability. They also need to be aligned with the size and weight constraints imposed on such items of equipment, and address EMI and ESD requirements.

Wendy Jane Preston, Senior Technical Author, Harwin
Wendy has worked for Harwin since 1995. Her current role in Marketing includes writing informative articles for publication on Harwin.com and beyond, creating technical and product launch documentation to support social media and Sales channels.

During her time with Harwin, Wendy’s first role as a Design Engineer saw her responsible for developing custom and standard products including Datamate J-Tek and Mix-Tek connectors. She has also held Technical Support and Legislation Officer roles at the company. She holds a BEng (Hons) degree in Manufacturing Engineering from Brunel University.