Cause of Device-Related Incident
Device factors; User errors

Clinical Specialty or Hospital Department
Cardiology / Cardiac Catheterization; CCU / ICU / NICU; Clinical/Biomedical Engineering; Obstetrics and Gynecology; OR / Surgery; Pharmacy / IV therapy

Device Factors
Device failure

Document Type
Hazard Reports

External Factors
*Not stated

Mechanism of Injury or Death
Failure to deliver therapy

Support System Failures
*Not stated

Tampering and/or Sabotage
*Not stated

User Errors
Abuse of device

Membrane Switch Failures



Hazard [Health Devices Jun 1986;15(6):184]

Problem

Many electronic medical devices have membrane (touch-panel) control switches. These switches offer resistance to fluid entry, thereby reducing the possibility of electrical shock and switch malfunction. To avoid inadvertent activation, many manufacturers have designed these switches so that they require greater force to activate. ECRI received several reports of membrane switch failures due to operator abuse. Personnel have damaged the membrane switches by using sharp instruments to activate them.

Discussion

A damaged switch may cause a device to operate in a hazardous manner. For example, a member hospital reports that the clear volume membrane switches on 4 of its 15 patient-controlled analgesic infusion pumps have been damaged by user abuse. When the switch has been punctured or bent inward by sharp instruments, it often remains closed, causing the pump to continuously clear the volume infused display. Because no alarms indicate this malfunction, a user who has set the pump to infuse a selected-volume dose may later find no indication on the display that any medication was administered. This may cause the user to inadvertently repeat the dose.

ECRI is aware of another common clinical situation in which membrane switches are abused. To avoid breaking sterile technique, a surgeon may activate nearby nonsterile electronic equipment with a sharp, sterile hemostat or scalpel and then discard the instrument. At one hospital, the membrane switches on an electrosurgical unit (ESU) were damaged because surgeons routinely used hemostats to reset the energy levels. The switches were riddled with puncture holes and lost the capability to set the energy levels. Fortunately, these switch failures did not cause the unit to operate in a hazardous manner. If the switch failures had resulted in intermittent contact, the set energy level might have spontaneously changed, leading to the use of inappropriate energy levels during a specific procedure and possible patient injury.

ECRI encourages the use of fail-safe medical device designs. However, we believe that the described failures are not due to an inherent design or manufacturing defect, but to operator error. The aforementioned problems are not limited to infusion pumps and ESUs, but include all electronic equipment with membrane switches.

Recommendations

  1. Advise all hospital personnel not to use instruments to activate membrane switches on electronic equipment, and alert them to potential problems associated with membrane switch damage.
  2. Incorporate this information into in-service training programs for hospital staff.
  3. Alert surgeons and other operating room staff members to the danger of using surgical instruments to activate any electronic equipment controls. Remind surgeons to ask the circulating nurse to adjust nonsterile equipment controls.
  4. Check membrane switches visually and functionally during routine equipment inspections. In addition to repairing abused switches, bring this situation to the attention of users, and determine why the abuse has occurred and how to avoid it.

Cause of Device-Related Incident

Device factor: Device failure

User error: Abuse of device

Mechanism of Injury or Death

Failure to deliver therapy


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