(Article reprinted from Medical Product Safety (MedSun) News, Volume 7, Issue 2 (February 2007), p. 24.)
Reported malfunctions with External Defibrillators (ED) particularly with the “hands-free” configurations indicate failures in the cables and their connectors. These failures were not discovered during routine functional tests but only when an attempt was made to use them on a patient. The failure to deliver possible life sustaining electrical energy to the patient’s heart in a timely manner may contribute to an adverse event including the death of the patient.
In brief, a defibrillator is a device that delivers an electrical shock of energy for defibrillating (restoring normal heart rhythm) the atria or ventricles of the heart or to terminate other cardiac arrhythmias. The device may either synchronize the shock with the proper phase of the electrocardiogram or may operate asynchronously. There are two basic defibrillator patient contact configurations known as the “paddles” and the “hands-free.” With the paddles, the healthcare professional or device user holds the wired contact paddles on the patient while the shock is delivered through them to the heart. With the “hands-free” configuration disposable electrode-pads are adhesively attached to the patient, and they connect to the defibrillator unit via a reusable interface cable and connectors to deliver energy to the patient. The “hands-free” terminology refers to the fact that the user’s hands are not needed to hold the pads in place when the shock is delivered from the defibrillator power unit.
The Medical Product Safety Network (MedSun) received several adverse event reports describing ED malfunctions attributable to cables and their connectors. These failures are not product or source specific but across defibrillator manufacturers.
The following are summaries of a few of these reports:
- On one occasion, a nurse tried to attach the hands-free pad to the hands-free interface cable. It would not attach. The nurse found that the defibrillator hands-free electrode cable end was broken and would not align with the connector of the external multifunction electrode pad. The interface cable had to be replaced. It was believed that the twisting motion used during removal of the test load (testing done daily) put stress on the connector causing the break.
- In this case, a nurse was unable to defibrillate a patient using the hands-free pads and interface cable. A switch was made to the paddles-cable and defibrillation was achieved.
A second defibrillator was later requested and it also failed to work in the hands-free mode, but did work when the paddles were attached.
The last self test on the original defibrillator unit was performed the day before the failure, but the last time the pad interface cable was tested with this defibrillator was about a month before. The underlying causes of the “hands-free” failure were that the staff was unaware that an audible “click” would confirm the proper seating of each connector, and they were unable to recall (seeing) a system or momentary error message on the unit’s display.
Cables and their connectors are often the source of hands-free defibrillator failures. The following recommendations are designed to assist user facilities and staff in minimizing these types of occurrences during both testing and patient defibrillation.
- Perform a functional test of the defibrillator at least once a day or per the facility’s or manufacturer’s protocol.
- Be sure to test the unit on battery power only.
- Be sure that all accessories such as ECG electrodes, lead wires, hands-free pads, cables and paper are present.
- Check for expiration dates on disposable products such as electrodes and hands-free pads.
- Keep records of these tests.
- Report within your facility any failures including mechanical faults such as bent or broken connector pins and/or cables, and electrical malfunctions such as open circuits or failure to deliver selected energy level.
- Test the defibrillator system with an external load making sure to include the interface cable.
- Keep the hands-free interface cables plugged into the test load as a protective measure when the device is not in-use if feasible. This measure can reduce the wear and tear from the frequent attaching and detaching of the connectors and the cables. The other ends of the cables can be connected to the defibrillator, if your facility’s protocol allows.
- Test the defibrillator system at least once every six months test to ensure that the system will reliably produce the maximum energy level that will be used on patients.
- Keep in mind that the interface cables (and other included wires) are subject to various mechanical bending and twisting during use.
- Functionally testing the cables may be helpful for early detection of connection issues which can cause intermittent opens/shorts. Check the User Manual for your particular make and model of defibrillator.
- Position the cables and connectors within easy reach of device users. This will prevent user over reaching and stretching during a code event that may lead to bending/breaking, incomplete mating and/or no connection of the pins.
- Train all device users to check the display screen and/or to listen for an audible clicking sound. These are feedback mechanisms from defibrillators that confirm positive connections. Look for possible messages that may indicate a connection has or has not been established.
- Provide the most current instructions for use with each defibrillator model during daily testing and preventive maintenance procedures, including any manufacturer’s suggested checklists.
- Provide adequate staff training according to user facility’s policies and procedures.
- Provide the manufacturer’s technical support and emergency contact phone numbers near the defibrillator for easy contact if device does not operate properly.