Fluke Biomedical VT Plus HF - Manual (Page 53)

Operation
Measured Signals
3
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Measured Signals
The Analyzer measures the following signals:
• High flow
• Low flow
• Airway pressure
• Low pressure
• Barometric pressure
• High Pressure
• Oxygen concentration
• Calculated breath parameters
High Flow
The Analyzer has a high-flow ( ± 300 LPM), bi-directional flow measurement. Flow
measurements can be either static flows (no breath variations) or ventilator waveforms
(i.e., both an expiratory and an inspiratory phase). The flow measurement is made using a
differential pressure drop across a resistive screen mesh. This flow measurement can be
used for pediatric/adult ventilators or for determining the performance of many types of
flow meters. Valves switch between the low-flow and the high-flow measurements
depending on the range selected in the display flow screens.
Low Flow
The Analyzer has a low-flow ( ± 25 LPM), bi-directional flow measurement. The flow
measurements can be either static (no breath variations) or ventilator waveforms (i.e.,
both an expiratory and an inspiratory phase). Flow measurements are made using a
differential pressure drop across a resistive screen mesh. The low-flow signal can be used
for infant/neonatal ventilators or for determining the performance of many other types of
flow meter. Valves switch between the low-flow and the high-flow measurements
depending on the range selected in the display flow screens.
Airway Pressure
The airway pressure is measured from a tap off of the proximal (near the exhaust port) of
the flow sensor housings. This tap is connected to a ± 120 cmH
2
O pressure sensor that
generates the airway pressure signal. Valves switch between the low-flow and the high-
flow measurements. When the low-flow port is selected, the airway pressure is measured
off the low-flow port. Likewise, when the high-flow port is selected the airway pressure
is measured off the high-flow port. Use the RANGE soft key from any of the flow
screens to select which flow port (high or low) airway pressure is measured from.
Low Pressure
This is a dual-port connection consisting of a (+) positive and a (-) negative pressure port.
The differential pressure range is ±500 mmHg. This pressure measurement can be used
for any pressure differential or gauge pressure in the given range. The transducer is
capable of measuring fluid pressure on the (+) positive port as indicated on the label.