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Pulmonary Function Test • Publication 014181-001 Rev 02 • www.datasci.com ©2023 Data Sciences International
Appendix A - Troubleshooting
This section provides general information that may help you resolve common user questions or problems.
If you require additional assistance, please contact DSI Technical Support or email support@datasci.com.
Common Reasons PFT Tests Might Fail
This section lists the most common reasons the FRC, PV, and FV tests fail
FRC Test
• Occlusion is not triggered
o This can happen if the end of the breaths cannot be determined during the breath history phase.
Occlusion is triggered at zero pressure when the previous breath ends.
o Make sure the calibration zero is good for all leads.
o Check the system for leaks (See the Leaks section below).
o If breaths are erratic during the breath history phase, check the anaesthesia.
• No breathing efforts during occlusion
o This can happen if the subject has been ventilated and is hyperventilated and is not trying to
breath. See the Appendix C section below for more details
PV Test
• The inspiration to 30 cm H20 phase of the PV test is not triggered
o This can happen if the end of the breaths cannot be determined during the breath history phase.
The inspiration phase is triggered at zero pressure when the previous breath ends.
o Make sure the calibration is good for all leads.
o Check the system for leaks (See the Leaks section below).
o If breaths are erratic during the breath history phase, check the anesthesia.
• 30 cm H20 of pressure cannot be achieved during the inspiration phase
o There could be a leak in the tracheal tube surgery. Check the surgery site and the tubing
connection to the manifold.
o The inspiration flow rate is too low. Increase in inspiration flow slightly and repeat the test (See
the Setting Inspiration Flow section on page 25).
o There could be a leak in the valves (See the Leaks section below)
o If you have a test lung for your species type, connect it and attempt the PV test. If the test
passes, the issue was probably with the tracheal surgery or the connection to the manifold. If it
still fails, try the other items in this list.
o 30 cm H20 must be reached within a unique specified time for each species, or the inspiration
will time out. Keep in mind that the rate you need to achieve for a “good” test is usually less than
the time out value (See the Setting Inspiration Flow section on page 25). For example, with mice
the inspiration time out is 5 seconds. However, the best inspiration rate for the average sized
mouse is to reach 30 cm H20 in 1-2 seconds.
• The slow expiration phase was too slow or too fast
o After the PV test is complete, check the Te value and compare to the values listed for your
species type (See the Setting Slow Expiration Flow section on page 26). If the Te is too high,
lower the slow expiration flow rate slightly. If the Te is too low, increase the slow expiration flow
rate slightly.
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