Vital Signs Monitor User Manual Monitoring SpO
2
- 77 -
Where:
Points = SpO
2
percentage points outside of the limit
Seconds = number of seconds that SpO
2
remains at that point outside of the limit
The alarm response time, assuming a SatSeconds limit set at 50 and a lower alarm limit set at 90,
is described and illustrated below.
In this example, the SpO
2
level drops to 88 (2 points below the limit) and remains there for a
period of 2 seconds (2 points
×
2 seconds = 4 SatSeconds). The SpO
2
then drops to 86 for 3
seconds and then to 84 for 6 seconds. The resulting SatSeconds values are shown below:
SpO
2
Seconds
SatSeconds
2
×
2 = 4
4
×
3 = 12
6
×
6 = 36
Total SatSeconds
=
52
After approximately 10.7 seconds, a SatSeconds alarm will be triggered, because the limit of 50
SatSeconds has been exceeded. See arrow (
↑
) in the following figure.
Alarm Response with SatSeconds
Saturation levels may fluctuate rather than remaining steady for a period of several seconds.
Often, the patient SpO
2
may fluctuate above and below the 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 SatSeconds limit is reached, or the patient SpO
2
returns within a normal range and remains there.