Philips Respironics V60, User Manual

Page: 55 / 212

Principles of operation
4-11
AVAPS mode
NOTE: When you adjust AVAPS minimum and maximum pressures,
remember that IPAP is adjusted to meet the target value. If the
calculated target pressure is outside of the minimum and maximum
pressure range, the target volume will not be achieved.
Unlike most pressure modes, the AVAPS (average volume-assured pressure
support) mode delivers a target tidal volume. It achieves the target volume by
regulating the pressure applied following an initial pressure ramp-up. The
AVAPS mode delivers time-cycled mandatory breaths and pressure-supported
spontaneous breaths.
If the patient fails to trigger a breath within the interval determined by the
Rate control, the ventilator triggers a mandatory breath with the set I-Time.
Mandatory and spontaneous breaths are delivered at a pressure that is
continually adjusted over a period of time to achieve the volume target, V
T
.
Min P and Max P define the minimum and maximum pressures that can be
applied. The patient triggers and cycles based on the ventilator’s Auto-Trak
Sensitivity algorithms.
At start-up, AVAPS applies an inspiratory pressure equal to one of the
following, whichever is greater:
• EPAP + (target volume / 60 ml/cmH
2
O)
• EPAP + 8 cmH
2
O
• Min P
The control settings active in the AVAPS mode are shown in Figure 4-12.
Figure 4-13 shows AVAPS mode waveforms.
Figure 4-12: AVAPS controls