CareFusion LTV 1200 Service Manual page 85

Symptoms
Monitored volume is
high.
Delivered volume is
high.
Page 7-8
Possible Causes
Very small ET tube
connected directly to wye.
Low side sense line or
elbow at patient wye loose
or leaking.
High or low sense lines are
occluded.
High or low sense ports in
the wye are occluded.
Sense lines are reversed.
Failed auto zero.
VHome setting does not
match flow valve.
Bypass flexible tube
pinched.
Pinhole leaks in bypass
flexible tube.
Failed calibration.
®
LTV 1200, 1150, and 1100 Ventilator Service Manual
What to Do
A very small ET tube connected directly to
the wye may cause turbulence that causes
the flow differential to be read incorrectly.
To reduce this turbulence, add a short
larger bore extension between the ET tube
and wye. In this case, the monitored
volume is high, but the delivered volume is
accurate.
Check high and low pressure sense lines
to be sure they are correctly attached and
securely seated at both the ventilator and
wye ends.
Check the Luer fitting connections for
leaks.
Check the elbow connectors at the wye to
be sure they have not loosened or been
broken loose.
Verify lines are not occluded or pinched.
The sense lines are not designed to be
removed from either the wye or the Luer
fittings. If the sense lines have been
removed and replaced incorrectly, they
may not seal correctly when replaced.
Replace the patient wye and sense lines
with a known good assembly.
Perform an auto zero under XDCR ZERO
®
See the LTV 1200, 1150, or 1100
Ventilator Operator's Manual for more
information.
Correct the VHome setting. See Chapter 6
- Maintenance & Calibration.
If the bypass flexible tube is pinched, it
can usually be seen pressed against the
louver openings in the bottom of the
ventilator case.
Open the ventilator and remove the back
panel. Replace the back panel being sure
to fit the louvers in between the upper and
lower loop of the bypass flexible tube
before seating the back cover.
If the bypass flexible tube is leaking,
replace it.
Recalibrate the vent. See Chapter 6 -
Maintenance & Calibration for instructions.
If the problem reoccurs after careful
recalibration, a transducer may be drifting
excessively. Perform the Advanced Vte
Diagnostic Procedures, see page 7-23.
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p/n 18603-001, Rev. J