Fluke VT Plus HF Operator's Manual page 86

VT Plus HF
Operators Manual
7-8
Problem
Tidal Volumes are erratic
in bi-directional breath
detect mode
Tidal volumes different
than expected.
Possible Cause
Unit calibration is incorrect
Breath detection threshold
set too low. Noise from
ventilator is causing "false"
breaths.
User's expected value was
incorrect.
Flow baseline drifts,
causing a false non-zero
flow reading when flow was
actually zero.
VT PLUS HF is out of
calibration.
Gas settings are incorrect.
Correction mode is set to
BTPS or STPD instead of
ATP.
Corrective Action
If problem persists, call
Service.
Set the breath detection
threshold to a higher value.
Review expectations.
Zero the flow reading.
Consider using the auto-zero
mode.
If possible, verify calibration
with a 3-liter calibration
syringe. Ensure gas settings
are correct. With the VT
PLUS HF in the bi-directional
breath detect mode and the
gas correction mode set to
ATP, stroke syringe such
that flows are near the mid-
range for the flow sensor.
Compare the VT PLUS HF
tidal volume to calibration
syringe volume. If difference
is out of specification, return
unit for calibration.
Review VT PLUS HF gas
settings.
Set gas mode to appropriate
setting for your application.
Most applications may
require the ATP mode.