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Rev. 3.0
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BM3 User’s Manual
Quality of SPO2 Waveform
Under normal conditions, the SPO2 waveform corresponds to (but is not proportional to) the
arterial pressure waveform. The typical SPO2 waveform indicates not only a good waveform, but
helps the user find a probe placement with the least noise spikes present. The figure below
represents an SPO2 waveform of good quality.
Good Quality SPO2 Waveform
If noise (artifact) is seen on the waveform because of poor probe placement, the photo detector
may not be flush with the tissue. Check that the probe is secured and the tissue sample is not too
thick. Pulse rate is determined from the SPO2 waveform which can be disrupted by a cough or
other hemodynamic pressure disturbances. Motion at the probe site is indicated by noise spikes
in the normal waveform. (See the figure below.) It has been noted that letting the patient view
the SPO2 waveform enables them to assist in reducing motion artifact.
SPO2 Waveform with Artifact
Stability of SPO2 Values
The stability of the displayed SPO2 values can also be used as an indication of signal validity.
Although stability is a relative term, with a small amount of practice one can get a good feeling
for changes that are artifactual or physiological and the speed of each. Messages are provided in
the SPO2 values window to aid you in successful SPO2 monitoring.
