6-17
7. [Tslope]: Time of pressure rising
8. [TVapnea] or [ΔPapnea]: Tidal volume or inspiration pressure in apnea ventilation
cycle
9. [fapnea]: Frequency of apnea ventilation
10. [Apnea Tinsp]: Inspiration time of apnea ventilation
6.5.8 PRVC
PRVC is pressure regulated volume control ventilation mode. It implements delivering set
tidal volume by the 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 preset tidal volume. Ppeak will vary according to the tidal
volume setting and the resistance and compliance of the patient’s lungs. Pressure adjustment
increase of the ventilator cannot exceed 10 cmH
2
O for the first 3 cycles, and cannot exceed 3
cmH
2
O for each of the following cycles. The maximum pressure cannot exceed the pressure
alarm high limit-5 cmH
2
O.
The first PRVC delivered is experimental ventilation mode. And the gas delivery pressure of
the first cycle is 10 cmH
2
O+PEEP for the purpose of calculating compliance and resistance of
the system and patient’s lungs, and calculating pressure level based on the patient’s condition.
This pressure level will then be used as a regulating object for tidal volume control in the
following ventilation cycles.
The following figure shows typical waveforms in PRVC mode.
↑△Paw≤10 cmH2O
↑△Paw≤10 cmH2O
↑△Paw≤10 cmH2O
↑△Paw≤3 cmH2O
Paw≤Pmax-5cmH2O
Reducecontrolpressure