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Failure is not an option in the Operating Room

Abstract: When a patient’s life is in the balance, Operating Room equipment must function flawlessly. Even when an operation is not life-threatening, the surgeon and surgery team do not need the distraction of equipment failure. So reliability is of paramount importance in all the advanced electronics found in modern Operating Rooms. Nonetheless failures, though rare, are inevitable and then a second key factor comes into play – how easily can a failed unit be replaced? The answer lies in the number and type of connections between the unit and other equipment. This paper focuses on the diverse applications of Operating Room equipment and the cables that interconnect the equipment. Specifically, we examine the reliability and ease-of-use of connectors embedded in those cables, using the diverse range of connectors available from ODU-USA as best-in-class examples. 1. Introduction The twenty-first century Operating Room in many modern hospitals (Figure 1) bears little resemblance to its counterpart of the mid-twentieth century (Figure 2). What is obviously different is the addition of numerous electronic systems, none of which were even conceivable until the advent of modern electronic technology in the 1960’s. Many surgeries performed in today’s Operating Rooms were unthinkable back then; and surgeries that were possible, such as appendectomies, were much riskier than today.

Of course, not all risk minimization is the result of electronic systems. Our better understanding of organ functions, much improved sterilization and surgery preparation methods, specialized intravenous medications, new surgical techniques and new types of surgical tools have also played their parts in achieving successful outcomes. However, in this paper we will focus on the impact of medical electronics, and specifically on the performance characteristics

Figure 2. Operating Room circa 1950

Figure 1. Modern Operating Room

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of the interface and cable connectors that couple the various devices.

As reliable as medical devices are designed to be, occasional failures are inevitable. Equipment failures during critical lifesaving surgery could be catastrophic for the patient, so minimizing the time to replace the failed device is of paramount importance. The cables that interconnect the device to other units must be easily disconnected; and once the device is replaced, the new unit must be just as easily and reliably connected in its place.

2. Operating Room Equipment and Applications Medical electronic systems used in the Operating Room fall into five broad categories – monitoring, diagnostic, treatment, life support and control systems. Each of these includes a variety of equipment, some of which are illustrated below. In addition, there are a number of ancillary systems that are present in almost all Operating Rooms, such as the surgical lights over the operating table and the headlights worn by surgeons. A common factor to devices in every one of these categories is that they all require cables.

Monitoring Systems These systems enable medical staff to continually assess a patient’s vital signs, and include devices such as the blood pressure monitor, electroencephalograph (EEG) for measuring brain activity, and the electrocardiograph (ECG) for measuring heart function.

Two examples of devices in this category are shown in Figures 3 and 4. The first, a hand-pulse oximeter, enables the continuous monitoring of pulse rate and oxygen saturation. The connection between the sensor and the device is provided by a plastic ODU MEDI-SNAP ® push-pull plug connector. Additional sensors are available for children and toddlers.

The second example, a fetal Doppler monitor, measures heart rate (FHR) in order to continuously analyze the health and condition of the fetus in the womb. The individual sensors also use the plastic ODU MEDI-SNAP® push-pull plug connector for coupling to the device.

ODU-USA is a major supplier of connector products to the medical industry (1),

due to the high quality and reliability of their products, plus a level of customer support that exceeds that of their competitors. In Section 3, we review the characteristics of such connectors that make them suitable for medical applications.

Diagnostic Systems

Figure 3. Hand-Pulse Oximeter

Figure 4. Fetal Doppler Monitor

Figure 5. MRI System set-up for brain scan

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Unlike monitoring systems that provide continuous assessment, diagnostic systems provide ‘video snapshots’ and include imaging systems based on a variety of technologies such as magnetic resonance imaging (MRI), computed tomography (CT) X-ray scanning and ultrasound.

MRI systems are used to create detailed cross-sectional images of the inside of the body, using radio frequency waves, powerful electromagnets and an integrated computer to interpret the signals generated by the machine. The most significant features of an MRI machine are its

ability to distinguish between normal and diseased tissue, and to precisely pinpoint the presence of cancerous cells. An MRI procedure normally takes 30-60 minutes. Through the use of an appropriate sub-system placed over the patient’s body, a specific area can be examined such as the brain, the inside of bones, the spine or the lungs. Figure 5 shows an MRI machine set-up to perform a brain scan. Power to the sub-system placed over the patient’s head, as well as data signals returned from that unit are both transferred via the ODU MAC® modular connector shown.

In Figure 6, the scanning sub-system contains multiple coils each of which is used to generate the magnetic field

directed at a specific area of the upper body. Each coil can be connected independently (one at a time) via the type of connector shown. Again, this connector provides the path for both power and data signals between the machine and the coil.

A third diagnostic system example is shown in Figure 7. In this case, an ODU MAC® connector acts as the interface between a mobile X-ray device and its monitor trolley. The connector provides paths for high current, data and signal transmission.

Treatment Systems Included in the category of treatment

systems are devices such as infusion pumps for supplying nutrient fluids or medications into a patient’s circulatory system or specific body organ, as well as medical lasers used for numerous

Figure 6. MRI System set-up for upper body scans

Figure 7. Mobile X-ray device

Figure 8. Multi-therapy infusion system

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purposes (cauterization, cancer cell destruction, vision correction, prostate surgery, and many others).

In Figure 8, an independent flow control system is shown that can be used with diverse types of infusion sources. It combines high-end volumetric infusion pump functionality with compact size and low weight.

Life Support Systems Devices in this category are used to temporarily replace the functions of an organ during surgery. They include dialysis machines, medical ventilators, and heart-lung machines.

Figure 9 shows a new kind of respiratory humidifier that connects between the respiratory device and the patient. It complements the functions of the respiratory device by warming and dampening the air. The patient is continuously provided with humidified air so that the mucous membranes do not dry out.

Two ODU MEDI-SNAP® push-pull plug connectors form the interface between the respiratory device and the humidifier. Assembly of the complete system is also performed by ODU.

Control Systems These are sub-systems that control the positioning of equipment used during surgery. Two examples are illustrated here.

In Figure 10, a hand-held unit is used to control the elevation and tilt of an operating table as well as raising and lowering of each section of the table. The interface to the hand-held unit for both power and data transfer is provided by ODU.

The hands free control system shown in Figure 11 enables a surgeon to control a neurosurgical microscope simply through movement of his/her head. This feature is extremely valuable for complicated and delicate operations lasting many hours. Optic parameters of the microscope can be adjusted with a joystick in the surgeon’s mouth.

Figure 11. Control system for neurological microscope

Figure 9. Respiratory humidifier

Figure 10. Hand Control Unit for Operating Table

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3. Connector Characteristics for the Operating Room Environment Many of the challenges normally faced by electrical connectors, such as harsh weather conditions and extreme temperatures, are insignificant in the Operating Room’s controlled environment. Nonetheless, some characteristics become still more important in evaluating the suitability of a connector for use with medical equipment: Reliability Over long periods of time, poor quality connectors may fail despite not being disturbed in any way (for example, no mating cycles performed – perhaps for several years). This may be the result of corrosion or oxidation on the pins or sockets. To avoid this, high quality connectors such as those manufactured by ODU, use gold plating on the contact surfaces.

Conversely, some medical systems require cable disconnections and reconnections several times each day. In this case, the measure of reliability is the number of mating cycles to which the connector may be safely subjected over its lifetime. Each ODU connector offers maximum mating cycles appropriate to its intended purpose, ranging from 2,000 to greater than 100,000 cycles. Ease of connection/disconnection Equipment failure during invasive surgery could have life-threatening consequences. If this were to occur, the Operating Room equipment technician must be able to rapidly disconnect and replace the failed unit, and then restore the connection in the minimum possible time. Several connector characteristics may come into play in this process:

Low and consistent mating/de-mating force. There must be no chance of the connector jamming during insertion.

Color-coded connectors where multiple cables are involved. This is exemplified by the ODU MEDI-SNAP® connector family (Figure 12), which offers 7 different colors.

Easy insertion with pin and groove alignment, also visible in Figure 12.

Secure locking to avoid accidental disconnection, which is implemented in both the ODU MEDI-SNAP® and ODU MINI-SNAP® connector families using a push-pull mechanism.

Cable consolidation to reduce the number of separate cables that need to be disconnected then re-connected. For this purpose, ODU offers the ODU-MAC® family of configurable modular connectors (Figure 13). With dozens of different inserts and a range of different shells and shell sizes, plus several locking options, ODU-MAC® is an ideal connector solution for complex medical applications. This flexibility enables ODU-MAC® to transmit signal, power, high current, high voltage, coax, high-speed data transmission,

Figure 12. ODU MEDI-SNAP® connector

Figure 13. One configuration of ODU MAC

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as well as fiber optic or other media such as air or fluid.

Current carrying capacity Devices such as the MRI scanner and X-ray scanner require high currents. Connectors capable of transmitting such currents must offer very low contact resistance for DC connections and very low impedance for AC connections, to ensure that sufficient power is delivered to the device. All manufacturers of connectors suitable for medical applications must meet this requirement, including ODU. Their ODU-MAC® connector includes inserts capable of handling currents as high as 220 Amps. Shielding As noted in Section 2, some medical systems, such as MRI scanners, utilize powerful electromagnets. This places a special demand on connectors used in the vicinity of those electromagnets; they must be constructed entirely of non-magnetic materials. For this reason, several of the ODU medical connector families offer optional plastic housings and pins/sockets made with non-magnetic gold-plated brass. 4. Medical Certification Requirements All of the requirements described above are incorporated into a number of U.S. and international standards with which reputable connector manufacturers must comply. Following are some of the more important standards:

ISO 9001 is the international standard that specifies requirements for a quality management system (QMS). Organizations use the standard to demonstrate the ability to consistently provide products and services that meet customer and regulatory requirements.

ISO 13485 Medical devices -- Quality management systems -- Requirements for

regulatory purposes is an International Organization for Standardization (ISO) standard published for the first time in 1996; it represents the requirements for a comprehensive quality management system for the design and manufacture of medical devices.

The ISO 14001 standard is the most important standard within the ISO 14000 series.

ISO 14001 specifies the requirements of an environmental management system (EMS) for small to large organizations. An EMS is a systemic approach to handling environmental issues within an organization.

UL 1977 applies to component connectors for use in data, signal, control and power

applications.

ODU has been certified to the ISO 9001 standard since 1994, and is also certified to the medical standard ISO 13485. Its additional certifications include DIN EN ISO 14001 as well as numerous VDE, UL, UL wiring harness, SCA, VG and MIL standards.

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ODU-USA is also registered with the US State Department - Directorate of Defense Trade Controls (DDTC) and is permitted to complete restricted manufacturing projects compliant with the International Traffic in Arms Regulations (ITAR).

5. Value Added Support Many medical equipment manufacturers choose to outsource production of the specialized cables required by their products. It seems obvious that the ideal source for such custom cables would be the manufacturer of the connectors used in those cables, since nobody knows better about selecting the cable whose characteristics match those of the connector. ODU is among the few manufacturers who offer this value-added service (2). 6. Conclusions During critical surgery, surgeons must be able to rely on their tools and equipment. No repetitive single point of failure can be tolerated. So while cables and connectors may be less complex than the electronics to which they are attached, their failure could be just as catastrophic as the failure of a piece of equipment costing tens of thousands of dollars! For that reason, only the highest quality connectors should be considered for use in the Operating Room environment – connectors that satisfy all the requirements discussed in this paper. ODU is one manufacturer whose products meet or exceed all the standards for medical applications and whose connectors have been chosen by world-class medical equipment manufacturers such as Philips Home Health Care, Abbott (formerly – St. Jude Medical), Stryker Medical, GE Medical, Medtronic, Alcon Manufacturing and many more. References (1) Advanced Medical Connector Solutions (http://www.odu-usa.com/applications/medical/) (2) Cable Assembly (https://www.odu-usa.com/connector-solutions/cable-assembly/)