Sleep Tech Tip of the Week

By Michael Miller, RPSGT

Artifact can be defined as an unwanted signal interfering with a channel on a PSG or EEG exam. One of the most prevalent and menacing artifacts most often observed is EKG artifact. EKG artifact is classified by an EKG waveform appearing in channels other than the actual EKG channel. EKG artifact is usually caused by a lead or electrode being place on a site where the patients pulse is evident. The picture below is an example of EKG artifact interfering with a PSG exam:

A simple correction for this problem to move the affected lead(s) or electrode(s) to a less affected site on the patient where the pulse is not as apparent. For example, if you are experiencing EKG artifact throughout the entire EEG portion of the record then move your reference electrodes (M1 and M2) to a more desirable location. The boney projection directly behind the patient’s ear is optimal.

Although EKG artifact does not inhibit scoring and review capabilities, it is a bit of a nuisance that interpreting physicians and scoring technologist would prefer to have eliminated when performing their duties. If EKG artifact correction is done prior to the lights out portion of the exam then it is best in order to avoid disturbing the patient during the actual acquisition.

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Tags: eeg, test preparation, troubleshooting medical equipment