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Figure 1-4. Gas delivery in the device
Within the ventilator, the gas enters the device’s pneumatic
system. An electronic mixer combines oxygen and air/heliox
according to the user-set concentration. This mixture fills a res-
ervoir, which is maintained within a prescribed pressure range.
As the gas mixture is delivered to the patient, the pressure
drops, and the reservoir is refilled.
Gas in the reservoir supplies the inspiratory valve. The micro-
processor controls the size of the inspiratory valve opening and
the length of time it is open to meet the user settings. The
opening of the valve is then adjusted based on feedback in the
form of monitored data.
The device delivers gas to the patient through the inspiratory
limb breathing circuit parts, including possibly the inspiratory
filter, flex tubes, the humidification system, a water trap, the
Y-piece, the CO
2
sensor and the flow sensor. An internal high
pressure valve supplies the nebulizer flow (oxygen).
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