Covidien Nellcor GR101704, Service Manual

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Theory of Operations
3-10 Service Manual
Third SpO
2
Event
Consider the third event. Suppose the SatSeconds alarm limit is still set to 25.
During this event, the patient’s SpO
2
drops to 75%, which is 10% below the
lower alarm threshold of 85%. Since the patient’s saturation does not return
to a value over the lower alarm threshold within 2.5 seconds, an alarm sounds.
At this level of saturation, the event cannot exceed 2.5 seconds without invok-
ing a SatSeconds alarm.
Figure 3-6. Third SpO
2
Event: Triggers SatSeconds Alarm
10% drop below the lower alarm limit threshold
x2.5 second duration below the lower threshold
25 SatSeconds ; results in an alarm