Nellcor OxiMax N-65, Operator'S Manual

Page: 26 / 152

Symbols, Controls, Displays, and Indicators
20 O
XI
Max N-65 Operator’s Manual
Decimal points after the %SpO
2
or pulse rate indicate
that the respective limits have been changed from the
power
- on default values.
There are various matrices within the signal processing
algorithm. Some of these are used to assess the severity
of conditions presented to the monitor in SpO
2
and pulse
rate measurements on a patient. Individual matrices, or
combinations of them, are used to drive the icon
indicators on the monitor front panel.
The signal processing algorithm increases the amount of
data required for measurements of SpO
2
and pulse rate
dependent on the measurement conditions. Throughout
normal measurement conditions, the averaging time is six
to seven seconds.
The signal processing algorithm extends the amount of
data required beyond seven seconds for measurement
conditions in which incoming signal quality is degraded,
such as:
• low perfusion
• active patients
• ambient light
• electromagnetic interference (EMI)
If the resulting dynamic averaging time exceeds 20
seconds, the
Pulse Search indicator appears and SpO
2
and Pulse Rate displays continue updating every second.
As these conditions extend, the amount of data required
continues to increase.
If the dynamic averaging time reaches 40 seconds, the
Pulse Search indicator flashes and the SpO
2
and pulse
rate displays flashing zeros to indicate a loss-of-pulse
condition.