Advanced Medical Connector Solutions

Medical connection systems are used to transmit power, data, and control signals to and from medical devices. They can be found in numerous clinical settings—surgical devices such as hand tools; therapeutic equipment; and diagnostic equipment such as EEG, ECG, EKG and EMG machines. They are also common in portable medical devices.

Connectors encompass more than just wires.Fiber-optic connection systems are employed for control signals, biomedical sensing, endoscopic imaging, and visible light transmission. Many medical connectors are incorporated into complex harnesses intended for one-time use.

When designing connectors for medical use, many factors must be considered, including FDA classification of the medical device, base electrical requirements including voltage and current, EMC and shielding requirements, and environmental requirements for specifying appropriate materials.

Operational Requirements

The most important requirement for connectors of course, is safety for both patients and medical personnel, followed by ease of use. Since they are used in hospitals and other clinical settings, they should be designed to be easily manipulated using surgical gloves.

Push-pull designs are preferred with an audible click to indicate successful engagement.Connectors and cablescan also be color-coded to ensure they are plugged into the proper receptacles. Unique mechanical coding can guarantee the correct connector is plugged into its proper mating connector.

In many cases, the patient connector is attached to a probe or similar device intended for one-time use, but the mating connector on the instrument itself should be robust enough to withstand as many as 5,000 mating cycles.

Since many physiological signals are very small-a typical electrocardiogram (ECG or EKG) signal has a peak amplitude, before amplification, of around 1 mV-it is important that the electrical characteristics remain consistent over the lifetime of the product. The low signal levels may also mandate EMC protections such as shielding. The rise of portable equipment as well as in-home devices has only increased the need for both robustness and ease of use.

Medical Connector Materials

As mentioned, a heat and chemical-resistant material is needed for medical connectors.PPSU, PSU and PEI are three thermoplastic high-performance plastics that feature a combination of thermal, electric and mechanical properties that make them suitable for medical use.

1. High upper-temperature limit for use in air

2. High mechanical strength, rigidity and creep resistance over a wide range of temperatures

3. Excellent resistance to hydrolysis (suitable for repeated steam sterilization)

4. High ductility, even at low temperatures

5. Harmless in physiological terms (suitable for contact with food)

6. Very high-dimensional stability

7. Translucent, non-optical quality (except for PPSU, which is black)

8. Very resistant to energy-rich radiation (gamma and X-rays)

9. Good electric insulation properties and positive dielectric behavior

Trends in Medical Connectors

With the rise in portable and in-home medical equipment, size and weight have become increasingly important. Miniature connectors are making their appearance, but with the smaller size means that increased attention must be paid to risk management factors such as clearance and creepage for higher-voltage signals.

Hybrids are another trend in connectors. Of course, electrical signals are vitally important, but many medical devices require “umbilical” connections that include fluid lines, and fiber-optic connections in addition to wires. To make sure everything is hooked up correctly. Specialized manufacturers are able to fill this need by incorporating multipleconnectors,cables and fluid lines into a single custom assembly.