6-16
8. [△Psupp]: Pressure support level
9. [fapnea]: Frequency of apnea ventilation
10. [F-Trig] or [P-Trig]: Inspiration trigger level
11. [Apnea Vent]: Apnea ventilation switch
6.7.8 PRVC
PRVC implements volume control by way of pressure control ventilation. In PRVC, a
relatively low pressure level is held as much as possible during the inspiratory phase and the
gas volume delivered is guaranteed to be equal to the set tidal volume. Pinsp will vary
according to the tidal volume setting and resistance and compliance of the patient’s lungs.
The ventilator adjusts Pinsp each time at a maximum increment of 3 cmH2O and the
maximum pressure does not exceed the pressure high alarm limit -5 cmH2O.
The first PRVC delivered is experimental ventilation mode for the purpose of calculating
compliance and resistance of the system and patient’s lungs based on which pressure level is
acquired. This pressure level will then be used for tidal volume control in the subsequent
ventilation cycles.
The following figures show typical waveforms in PRVC mode.
Paw
Flow
Time
Time
Paw≤alarm high limit-5cmH2O
↑Differential pressure≤3
cmH2O
Volume limit Reduce control pressure
Experimental
ventilation
In PRVC under non-NIV, you need to set the following ventilation parameters:
1. [O2%]: Oxygen concentration
2. [TV]: Tidal volume
3. [Tinsp] or [I:E]: Time of inspiration or ratio between the inspiratory and
expiratory time