Childhood Adenotonsillectomy Trial

6.5.8 PSG Equipment Care and Disinfection

All gold disk electrodes must undergo cleaning followed by intermediate level disinfection or higher between patients. The thermistor (Dymedix) is disposable. Cleaning and disinfection of PSG electrodes may be accomplished in accordance with the policy of the host laboratory, providing that between participants high level disinfection of the reusable gold disk electrodes is achieved.

The gold disk electrodes are re-useable and should last through many cycles of use. The weakest part of the electrode is the thin wire cable at the end of the gold disk. Since this wire is very thin and hidden by an opaque covering a broken, or bad, electrode may look perfectly fine yet yield distorted inaccurate information. The best way to determine if the electrode is working correctly is through the impedance test after the electrodes are placed on the participant. If the electrode yields unsatisfactory impedance levels after proper troubleshooting it is most likely time to replace the electrode.

Conditioning New Gold Disk Electrodes

Electrodes are durable objects with a long shelf life. They may have been manufactured long before they are shipped to the user. If spare electrodes are ordered, they may be kept in storage for a long time before they are needed as a replacement. In order to keep a new electrode looking fresh until the first use, it is treated with a coating before being packaged. If you have ever used a brand new electrode without conditioning it you may have been puzzled as to why your impedances were just as high as with the broken electrode. Sometimes the patient, the connecting cable or recording unit gets blamed. Condition new gold disk electrodes prior to the first use.

To condition a gold disk electrode for the first use, lightly brush both sides (top and bottom of the cup) with a stiff nylon brush or hair comb. Brush a new electrode well. The gold disk can then be washed with a soapy solution and rinsed with warm water. Lastly the gold disk is placed in some electrolyte (or smear some conducting paste on both sides). Allow the electrolyte to remain on the gold disk for several hours (or overnight). After the electrolyte soak, rinse to clean with warm water and dry. The electrode is now ready for the first use.

Gold Disks Electrodes – General Care

Keep Gold Disks Clean:

Between uses, the surface of the gold disk electrode must be kept free of dried electrolyte paste. An electrode with dried paste does not come into proper contact with the skin and creates an air pocket that increases impedance and distorts the signal. Additionally, an electrode with visible crusted paste cannot be properly disinfected. Insure the gold cup and the connection leading to the wire is free of crusted paste.

Treat Electrode Wires With Respect:

The weakest part of the electrode is the thin wire cable at the end of the gold disk. The most vulnerable place for injury to the wire is the point it interfaces with the gold cup or where it plugs into the patient cable. If the connection is loose at either of these places, the electrode cup may receive an adequate signal but it will never reach the recording unit. Since this wire is very thin and hidden by an opaque covering a broken, or bad, electrode may look perfectly fine yet yield distorted, inaccurate information. The wires should be kept clean and free of crusty paste or sticky tape. If tape is used for the participant hook-up, or a gob of paste ends up on the wires, it should be removed and the wires wiped to remove any stickiness. Never pull excessively on the electrode wire or bend the wire near the point of connection to the gold cup or patient interface cabling. Do not wind the wire around any small objects that may cause the wire to kink. After use, any knots that may have formed in the wire should be removed, and the wires straightened. To keep the wires from kinking during storage, after disinfecting electrodes the wires may be wrapped and secured around a larger object, such as an empty plastic water or soft drink bottle. Wires that are knotted or kinky can increase impedance.