Philips BiPAP A40 - 2.3 Therapy Event Detection; 2.3.1 Event Detection in Modes with a Back-up Rate

Chapter 2 Therapy Modes and Features
17
2.3 Therapy Event Detection
The device monitors breathing and detects apneas, hypopneas, and other therapy events
(as available).
Event Denition
Obstructed
Airway
Apnea/
Clear Airway
Apnea
Detection
An apnea is detected when there is an 80% reduction in airow from baseline for at least
10 seconds or if there is no airow 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 signicant amount of ow; otherwise, the airway is
determined to be obstructed.
RERA
Detection
RERA (Respiratory eort-related arousal) is dened as an arousal from sleep that follows a
10 second or longer sequence of breaths that are characterized by increasing respiratory
eort, 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 airow and progressive ow
limitation. If this breath sequence is terminated by a sudden increase in airow along with
the absence of ow 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
airow from an established baseline ow. The pattern must be present for several minutes
before it can be identied as periodic breathing.
Hypopnea
Detection
A hypopnea is detected when there is an approximately 40% reduction in airow 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.
2.3.1 Event Detection in Modes with a Back-up Rate
If the device is in a mode that delivers its own backup breath, (S/T, PC, T, or AVAPS-AE mode), then
the device will NOT deliver the test pulse. Instead, it will use the machine back-up breath and
evaluate it for which (if any) type of apnea to score.