Leakage Current And Tee Transducers; Reducing Risks Of Using Tee Transducers - Philips EPIQ 7 User Manual

Transesophageal Transducers
For safety information on electrosurgical units, pacemakers, defibrillators, and related topics,
see "Electrical Safety" on page

Leakage Current and TEE Transducers

For the TEE transducers discussed in this document, the insertion tube and tip are Type BF
as described in IEC 60601-1. There are no exposed conductive surfaces distal to the transducer
handle. Within the flexible shaft, all active circuits and conductors are surrounded by a chassis-
grounded shield that runs the length of the transducer.
If the outer layer of the shaft is punctured or cracked, a patient's esophagus could be exposed
to chassis leakage current. This leakage current is not hazardous provided that the ground
connector (third wire) in the ultrasound system power cable is intact and connected to a
properly grounded wall outlet. Even if the ground connector breaks, leakage current is in
compliance with the limits noted in IEC 60601-1.
Leakage hazards are further reduced when the ultrasound system is plugged into an isolated
power outlet, which is standard in most operating rooms.

Reducing Risks of Using TEE Transducers

WARNING
Before defibrillation, if you cannot remove the transducer from the patient, always
disconnect invasive transducers that remain in contact with the patient from the system.
To reduce the possibility of electrical risks associated with use of TEE transducers, follow these
recommendations:
• Visually and tactually inspect a TEE transducer for bumps, cracks, and cuts before each TEE
exam. A small bump on the shaft surface could indicate that a strand from the ground
shield has broken and is beginning to puncture the outer layer. If you suspect a problem
with the flexible shaft, perform the electrical safety check procedure. See
Current Test" on page
• Use electrosurgical units (ESUs) that have isolated outputs. Return fault/ground fault
detection circuits provide additional protection. To determine if an ESU has an isolated
output, read the label on the ESU, see the ESU service guide, or ask a biomedical engineer.
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Electrical Safety and TEE Transducers
"TEE Leakage
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