8 Monitoring SpO2
Assessing a Suspicious SpO2 Reading
Traditionally, pulse rate from SpO
the correct calculation of SpO
When pulse rate is very low, or strong arrhythmia is present, the SpO
heart rate calculated from ECG but this does not indicate an inaccurate SpO
If you doubt the measured SpO
perfusion indicator instead to assess the signal quality.
With pulse oximetry, sensor movement, ambient light (especially strobe lights or flashing lights) or
electromagnetic interference can give unexpected intermittent readings when the sensor is not
attached. Especially bandage-type sensor designs are sensitive to minimal sensor movement that might
occur when the sensor is dangling.
Changing the Averaging Time
Depending on the monitor configuration, you may be able to change the averaging time for the SpO
The averaging time represents the approximate time period used for the calculation. The exact
averaging algorithm depends on the SpO
longer the averaging time, the longer the time needed until the SpO
event. Fast averaging is useful for situations where an extremely fast measurement is required or few
artifacts are expected. Use slow averaging where you expect the number of artifacts to be relatively
Select the required averaging time from the list.
Understanding SpO2 Alarms
This refers to SpO
low alarm limit below the desat alarm limit.
reading. With newer algorithms, such as FAST-SpO
is not directly linked to the correct detection of each pulse.
, use the signal quality indicator (if available) or the pleth wave and
specific alarms. See the chapter on "Alarms" on page 47 for general alarm
offers high and low limit alarms, and a high priority desat alarm. You cannot set the
was compared with heart rate from ECG to confirm the validity of
technology (option) used and on the signal conditions. The
, this is no longer a valid criteria because
pulse rate may differ from the
value reflects the physiological