BM1VOM-1.24
5.SpO2 69
BM1VET Operation Manual
Signal and Data Validity
It is extremely important to determine that the probe is attached to the animal correctly and the data
is verifiable. To make this determination, three indications from the monitor are of assistance
—signal
strength bar, quality of the SPO2 waveform, and the stability of the SPO2 values. It is critical to
observe all three indications simultaneously when ascertaining signal and data validity.
Signal Strength Bar
The signal strength bar is displayed within the SPO2 values window. This bar consists of 15 blocks
set depending on the strength of the signal. Proper environmental conditions and probe attachment
will help to ensure a strong signal.
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 photodetector 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.)
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.
WARNING
In the monitoring of animals the coincidence of adverse conditions may lead to a disturbed
signal going unnoticed. In this situation artifacts are capable of simulating a plausible parameter
reading, so that the monitor fails to sound an alarm. In order to ensure reliable animal
monitoring, the proper application of the probe and the signal quality must be checked at
regular intervals.
