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Use of non-Natus supplied, or recommended components or accessories may prevent the application of the risk
control measures unique to Natus parts from being applied, which may cause electrical shock.
Damaged power cord contacting ungrounded metal component(s) may cause electrical shock.
Periodically check the system ground integrity, the system leakage current and the leakage current of the
amplifier.
Source currents to the patient due to use of a repaired components that have not been leakage tested may
cause electrical shock.
Improper external headbox connections may produce sourcing of current to the patient, which may cause
electrical shock.
Plugging an electrode into the headbox or amplifier and allowing the loose ends to make contact with hazardous
voltages can cause electrical shock.
Do not allow conductive parts of electrodes and connectors to contact conductive parts or ground.
Equipment not complying with IEC 60601-1 shall be kept outside the patient environment, as defined in the
standard, (at least 1.5m from the patient), which may cause electrical shock.
Observe IEC 60601-1 standards in case of connection with other instruments. The connection of the equipment
with other devices is allowed only when the safety requirements for the patient, the user and the environment
are not compromised.
The potential for electrical shock is present if device covers are removed. Refer servicing to qualified personnel.
Patient Supplies/Electrodes Interaction
Do not measure the impedance of needle electrodes with the needle positioned in the patient. This practice may
result in patient injury.
Do not measure the impedance of electrodes which are in contact with the patient’s cornea or eye. This practice
may result in patient injury.
To reduce the risk of injury, disconnect all recording and stimulating electrodes from the system before you turn
the system power off and on.
Prolonged electrical stimulation can cause a patient burn.
Use only electrodes of adequate size and properly applied by qualified medical personnel to avoid patient skin
reactions or burns.
Using electrodes with current densities greater than 2 mA r.m.s./cm2 may require the special attention of the
operator to avoid patient skin reactions or burns.
Electrodes of inadequate size or unsuitable application could provoke skin reactions or burns. Natus
recommends the use of disposable, pre-gelled, silver/silver chloride electrodes with a contact area of 20 mm
diameter or larger. These electrodes contain an adhesive that maintains the electrode skin position and contact
during electrical stimulation and are designed for use of the maximum output of the electrical stimulator.
The FDA has issued guidance to not exceed 0.25 W/cm2 on stimulating electrodes to prevent the possibility of
causing a burn due to excessive current densities at the site of prolonged stimulation. Table #1 below
demonstrates the how different stimulus parameters as well as electrode impedance affect the minimum size.
