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VT Plus HF
Operators Manual
4. Ensure that the ventilator is delivering breaths in a steady manner.
5. Gently lift the back of the test lung top plate during the expiratory hold period in a
6. Repeat several times using different forces to approximate the minimum patient
To carry out a more repeatable performance study, such as the
determination of the work of breathing, attach an external, motor-driven
cam system or a pneumatic actuator to the top plate of the test lung.
High Frequency Oscillator Mode
The Analyzer can test high-frequency flow and airway pressure.
To access the High-Frequency Oscillator mode:
1. Press the MORE/4 key.
2. Use the
3. Press the ENTER soft key. The High Freq. Test screen displays:
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smooth, steady pull to create negative pressure.
effort required to trigger the ventilator.
The Full Test screen shows all of the ventilator parameters. The minimum pressure
and the assist pressure are displayed on the lower left column.
and
soft keys to highlight High Frequency Oscillator.
The high-frequency oscillator (HFO) mode samples flow and airway pressure at a
much faster rate (5x) than the Analyzer does in normal operation. It is useful for
monitoring the function of extremely high-frequency breath rates, up to 800 bpm. In
HFO mode, the Analyzer collects two seconds worth of data at a time. After the data
is collected, it is processed to calculate parameters, and the first half-second of data is
plotted on the display.
The mean, min, and max values are calculated for both pressure and flow signals.
These values apply to the entire two seconds of data, not just the half-second that is
plotted. The breath rate is calculated and displayed in both breaths per minute and
Hz. The inspiratory time and tidal volume are also calculated.
Note
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