Respironics BiPAP Focus Operator's Manual page 37

• The spontaneous expiratory threshold (SET) algorithm (Figure 18)
raises the threshold in proportion to the inspiratory flow rate for
each breath. When the SET and actual patient flow value are equal,
the system cycles to EPAP.
• Maximum inspiratory time: A maximum IPAP time of 3.0 seconds
acts as a safety mechanism to limit the time spent at the IPAP level
during spontaneous breathing in S/T mode. If 3.0 seconds elapse in
IPAP, the system automatically cycles from IPAP to EPAP.
• Flow reversal: As flow begins to decrease during IPAP, a flow
reversal can occur due to a large leak around the mask or because
the patient's mouth is open. When the system senses this flow
reversal, the unit automatically cycles to EPAP.
PRESSURE
Estimated
patient
FLOW
®
BiPAP Focus™ Noninvasive Ventilator System
1027404 Rev K
IPAP
EPAP
Shape
signal
flow
Figure 17: Shape Signal
Cycle to
EPAP
crossover
point
Trigger to
IPAP
crossover
point
Operation
31