6-18
6.7.9 DuoLevel
DuoLevel is double level positive airway pressure ventilation. In DuoLevel, the ventilator
delivers positive airway pressure at two pressure levels alternatively during mechanical
ventilation or spontaneous breathing. The patient can breathe spontaneously at either pressure
level. During the low pressure phase, pressure support can be set. Trigger window is available
during both high and low pressure phases. The trigger window during the low pressure phase
is the later 5 seconds of low pressure time (Tlow) while the trigger window during the high
pressure phase is the later 1/4 of high pressure time (Thigh). Within the trigger window of
low pressure phase, inspiratory trigger transforms to high pressure gas delivery. Within the
trigger window of high pressure phase, expiratory trigger transforms to low pressure gas
delivery.
The following figure shows typical waveform in DuoLevel mode.
Paw
Time
Phigh
Trigger
window
Trigger
window
¼
Thigh
PSV
Tslope
5s
Thigh
Plow
Tlow
5s
Trigger
window
Insp. trigger
Exp.trigger
In DuoLevel under non-NIV, you need to set the following ventilation parameters:
1. [O2%]: Oxygen concentration
2. [Phigh]: High pressure
3. [Thigh]: Time of high pressure
4. [Plow]: Low pressure
5. [Tlow]: Time of low pressure
6. [Tslope]: Time of pressure rising
7. [Exp%]: Expiration trigger level
8. [△Psupp]: Pressure support level
9. [ΔPapnea]: Pressure of apnea ventilation
10. [fapnea]: Frequency of apnea ventilation
11. [F-Trig] or [P-Trig]: Inspiration trigger level
12. [ATRC]: Automatic tube resistance compensation