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Pulmonary Function Test • Publication 014181-001 Rev 02 • www.datasci.com ©2023 Data Sciences International
System Calibration
To calibrate the PFT signals, you need to calibrate 2 or 3 transducers. These include flow, mouth pressure, and
(optionally) pleural pressure. The flow transducer requires 3 separate calibrations since it appears on 3 leads, each
lead at a different sensitivity: High Flow, Flow, and FRC Flow.
You should calibrate once at the start of each day you intend to use the system. Calibration is a quick check that
key parts of your system are functioning properly. For example, when you calibrate Mouth pressure, you also test
the manifold for leaks. When you calibrate flow, you test the plethysmograph for linearity and gross changes in
sensitivity.
Definitions of Signals
The following is a list of leads that you might use during your maneuvers.
High Flow is the low gain flow signal for measuring high flow rates during the FV
tests. High Flow is negative on inspiration.
Flow is amplified an extra 4 or 8 times depending on the species, (jumper
selectable on the Signal Generator Module) for normal flow rates. Flow is
negative on inspiration.
A more sensitive flow signal which is used to measure flow while the animal
is occluded. Flow x 5.
Pressure
Mouth Pressure is the pressure at the mouth of the subject. Its purpose is to
monitor the lung inflation and to protect the subject’s lungs from dangerous
pressure levels.
Mouth pressure is positive when higher pressure is applied to the airway.
Pressure
Pulmonary Pressure is the lung pressure. This can be esophageal pressure
measured with an esophageal catheter.
Valves
The four solenoid valves in this system can set to be controlled by the computer (Auto mode) but may also be
thrown manually (On or Off). The combined operation of these valves distinguishes the three different maneuvers.
When open for inspiration, air is forced into the animal’s lungs at
the set flow rate.
This valve performs a fast expiration. It is connected directly to
the Negative Reservoir. When open, there is little to no
resistance as the air is quickly sucked out of the animal’s lungs.
This valve is connected to the negative reservoir through the
Slow Expiration Flow control valve on the front panel. When
open, this valve forces the animal to expire at the set flow rate.
This is a low resistance valve. When activated (closed), it blocks
the animal’s air path. When no test is running, it is open,
allowing the animal to breath voluntarily.
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