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ANUAL
5.12 Therapy Event Detection
Text
Description
Obstructed airway
apnea/
Clear airway apnea
detection
An apnea is detected when there is an 80% reduction in airflow from
baseline for at least 10 seconds or if there is no airflow detected for
10 seconds. During the apnea, one or more pressure test pulses are
delivered by the device. The device evaluates the response of the
patient to the test pulse(s) and assesses whether the apnea has
occurred while the patient has a clear airway or an obstructed airway.
The airway is determined to be clear if the pressure test pulse
generates a significant amount of flow; otherwise, the airway is
determined to be obstructed.
RERA
detection
RERA (Respiratory effort-related arousal) is defined as an arousal
from sleep that follows a 10 second or longer sequence of breaths
that are characterized by increasing respiratory effort, but which does
not meet criteria for an apnea or hypopnea. Snoring, though usually
associated with this condition, need not be present. The RERA
algorithm monitors for a sequence of breaths that exhibit both a subtle
reduction in airflow and progressive flow limitation. If this breath
sequence is terminated by a sudden increase in airflow along with the
absence of flow limitation, and the event does not meet the conditions
for an apnea or hypopnea, a RERA is indicated.
Periodic
breathing
A persistent waning and waxing breathing pattern which repeats itself
between 30 and 100 seconds. The nadir of the breathing pattern is
characterized by at least a 40% reduction in airflow from an
established baseline flow. The pattern must be present for several
minutes before it can be identified as periodic breathing.
Hypopnea
detection
A hypopnea is detected when there is an approximately 40%
reduction in airflow from baseline for at least 10 seconds.
Snore
detection
Vibration snore is disabled at pressures greater than 16 cmH
2
O in
CPAP mode. Vibration snore is disabled at IPAP settings greater than
20 cmH
2
O or max pressure support (IPAP – EPAP) greater than or
equal to 10 cmH
2
O in bi-level modes. It is also disabled during any
machine triggered breaths when EPAP settings are greater than or
equal to 10 cmH
2
O.
Large leak
The level of leak is so large, it is no longer possible to determine
respiratory events with statistical accuracy.
