Principles of operation
4-8
CPAP mode
In the CPAP (continuous positive airway pressure) mode, the ventilator
functions as a demand flow system, with the patient triggering all breaths and
determining their timing and size. The patient triggers and cycles based on the
ventilator's Auto-Trak Sensitivity algorithms. The control settings active in the
CPAP mode are shown in Figure 4-6. Figure 4-7 shows CPAP mode waveforms.
The C-Flex feature setting enhances traditional CPAP by reducing the pressure
at the beginning of exhalation – a time when patients may be uncomfortable
with CPAP – and returning it to the set CPAP level before the end of exhalation.
CPAP
I
Figure 4-6: CPAP controls
E
Time
Figure 4-7: CPAP waveforms