Mindray VS-900, Operator'S Manual

Page: 74 / 192

7-6
Saturation levels may fluctuate rather than remaining steady for a period of several
seconds. Often, the patient % SpO
2
may fluctuate above and below an alarm limit,
re-entering the non-alarm range several times. During such fluctuation, the monitor
integrates the number of %SpO
2
points, both positive and negative, until either the
Sat-Seconds limit is reached, or the patient%SpO
2
re-enters the non-alarm range and
remains there.
7.5.7 Changing the Speed of Pleth Wave
In the [ SpO
2
Setup ] menu, select [ Sweep ] and then select the appropriate setting. The
faster the waveform sweeps, the wider the waveform is.
7.5.8 Setting the Alarm Level for SpO
2
Sensor Off Alarm
In the [ SpO
2
Setup ] menu, select [ SpO
2
Sensor Off Lev. ] and then select the appropriate
setting.
7.6 Measurement Limitations
If you doubt the measured SpO
2
, check patient vital signs first. Then check the equipment
and SpO
2
sensor. The following factors may influence the accuracy of measurement:

Ambient light

Physical movement (patient and imposed motion)

Diagnostic testing

Low perfusion

Electromagnetic interference, such as MRI environment

Electrosurgical units

Dysfunctional haemoglobin, such as carboxyhemoglobin (COHb) and
methemoglobin (MetHb)

Presence of certain dyes, such as methylene and indigo carmine

Inappropriate positioning of the SpO
2
sensor, or use of incorrect SpO
2
sensor

Drop of arterial blood flow to immeasurable level caused by shock, anemia, low
temperature or vasoconstrictor.