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5.3. Environmental and Medical Therapy Hazards
! Patients should exercise reasonable caution in avoiding devices that generate
a strong electric or magnetic field. (For examples, see the “Other
Environmental Hazards” section of this manual.) If a Pulse Generator ceases
operation while in the presence of electromagnetic interference (EMI),
moving away from the source may allow it to return to its normal mode of
operation.

5.3.1. Hospital and Medical Environments
! NCP System operation should always be checked by performing device
diagnostics after any of the procedures mentioned in this manual. Additional
precautions for these procedures are described below.
! Because of where the Pulse Generator is implanted in the chest, patients may
need to be specially positioned in mammography equipment for clear
imaging. Otherwise, the device may be seen as a shadow on the
mammogram. (Most routine diagnostic procedures, such as fluoroscopy and
x-radiography, are not expected to affect system operation.)

! Therapeutic radiation may damage the Pulse Generator’s circuitry, although
no testing has been done to date and no definite information on radiation
effects is available. Sources of such radiation include therapeutic
x-rays, cobalt machines, and linear accelerators. The radiation effect is
cumulative, with the total dosage determining the extent of damage. The
effects of exposure to such radiation can range from a temporary disturbance
to permanent damage, and may not be detectable immediately.

! External defibrillation may damage the Pulse Generator. Attempt to
minimize current flowing through the Pulse Generator and Bipolar Lead
system by following these precautions:
�� Position defibrillation paddles perpendicular to the Pulse Generator and Bipolar Lead
system and as far from the Pulse Generator as possible.
�� Use the lowest clinically appropriate energy output (watt-seconds).
�� Confirm Pulse Generator function after any internal or external defibrillation.

! Electrosurgery may damage the Pulse Generator. Attempt to minimize the
current flowing through the Pulse Generator and Bipolar Lead system by
following these precautions:
�� Position the electrosurgery electrodes as far as possible from the Pulse Generator and
Bipolar Lead.
�� Avoid electrode placement that puts the Pulse Generator or Bipolar Lead in the direct
path of current flow or within the part of the body being treated.
�� Confirm Pulse Generator functions as programmed after electrosurgery.

! If the patient receives medical treatment for which electric current is passed
through the body (such as from a TENS unit) either the Pulse Generator
output should be set to 0 mA or function of the Pulse Generator should be
monitored during initial stages of treatment.

! Magnetic resonance imaging (MRI) should not be performed with a
magnetic resonance body coil in the transmit mode. The heat induced in the
Bipolar Lead by an MRI body scan can cause injury.
If an MRI should be done, use only a transmit and receive type of head coil.
Magnetic and radiofrequency (RF) fields produced by MRI may change the
Pulse Generator settings (change to reset parameters) or activate the device.
Stimulation has been shown to cause the adverse events reported in the
“Adverse Events” section of this manual. MRI compatibility was
demonstrated using a 1.5T General Electric Signa Imager only. Testing on
this imager as performed on a phantom2 indicated that the following Pulse
Generator and MRI settings can be used safely without adverse events:
♦ Pulse Generator output programmed to 0 mA for
the MRI procedure, and afterward, retested by performing the Lead Test
diagnostics and reprogrammed to the original settings
♦ Head coil type: transmit and receive only
♦ Static magnetic field strength: ≤ 2.0 tesla
♦ Specific-rate absorption (SAR): < 1.3 W/kg
for a 154.5-lb (70-kg) patient
♦ Time-varying intensity: < 10 tesla/sec
Use caution when other MRI systems are used, since adverse events may occur
because of different magnetic field distributions.

! No scan in which the radiofrequency (RF) is transmitted by the body coil
should be done on a patient who has the NCP System. Thus, protocols must
not be used which utilize local coils that are RF-receive only, with RFtransmit
performed by the body coil. Note that some
RF head coils are receive only, and that most other local coils, such as knee
and spinal coils, are also RF-receive only. These coils must not be used in
patients with the NCP System.

! Therapeutic ultrasound. Routine therapeutic ultrasound could damage the
Pulse Generator and may be inadvertently concentrated by the device, causing
harm to the patient.

! Extracorporeal shockwave lithotripsy may damage the Pulse Generator. If
therapeutic ultrasound therapy is required, avoid positioning the Pulse
Generator part of the body in the water bath or in any other position that
would expose it to ultrasound therapy. If that positioning cannot be avoided,
program the Pulse Generator output to 0 mA for the treatment, and then after
therapy, reprogram the Pulse Generator to the original parameters.
Diagnostic ultrasound is not expected to affect the NCP System.


5.3.2. Home Occupational Environments
! The patient should seek medical advice before entering environments which
are protected by a warning notice preventing entry by patients fitted with a
pacemaker.
Properly operating microwave ovens, electrical ignition systems, power
transmission lines, theft-prevention devices, and metal detectors are not expected
to affect the Pulse Generator. Similarly, most routine diagnostic procedures, such
as fluoroscopy and x-radiography, are not expected to affect system operation.
However, because of their higher energy levels, sources such as transmitting
antennas may interfere with the NCP System. It is suggested that the Pulse
Generator be moved away from equipment—typically at least six feet
(1.8 meters)—that may be causing interference.

5.3.3. Cellular Phones
Based on testing to date, cellular phones have no effect on Pulse Generator
operation. Unlike an implanted pacemaker or defibrillator, the Pulse Generator
does not sense physiologic signals.

5.3.4. Other Environmental Hazards
! Strong magnets, hair clippers, vibrators, loudspeaker magnets, and other
similar electrical or electro-mechanical devices, which may have a strong
static or pulsing magnetic field, can cause accidental magnet activation.
Patients should be cautioned to keep such devices away from the Pulse
Generator, typically at least six inches (15 centimeters) away.

5.3.5. Programming Software
The NCP Programming Software should be used on a computer dedicated only to
programming the NCP System. The Programming Software has been validated on
a Compaq Contura Aero 4/25 running MS DOS 6.2 with the disk-caching
software disabled. (See the NCP Programming Software physician’s manual for
more information.)

5.3.6. Pulse Generator and EMI Effects on Other Devices
During stimulation, the Pulse Generator may interfere with devices operating in
the 40 kHz to 100 kHz range, such as pocket transistor radios and hearing aids.
This interference is a theoretical possibility, and no effects on hearing aids have
yet been reported, although the Pulse Generator can interfere with a transistor
radio when held directly over one. No specific testing has been done to date, and
no definite information on effects is available.

The Pulse Generator should be moved—typically at least six feet (1.8 meters)—
away from equipment with which it may be interfering.
Programming or interrogating the Pulse Generator may momentarily interfere
with other sensitive electronic equipment nearby. The Pulse Generator is not
expected to trigger airport metal detectors or theft-protection devices that are
closer than about six feet (1.8 meters).

! The Pulse Generator may affect the operation of other implanted devices,
such as cardiac pacemakers and implantable defibrillators. Possible effects
include sensing problems and inappropriate Pulse Generator responses. If the
Pulse Generator patient requires concurrent implantable pacemaker and/or
defibrillator therapy, careful programming of each system is necessary to
optimize the patient’s benefit from each device.

! The magnet provided for activation or inhibition of the Pulse Generator may
damage televisions, computer disks, credit cards, and other items affected
by strong magnetic fields.

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