Fluke Biomedical VT305 - Manual (Page 54)

VT305
Users Manual
40
of air, the 3 l/min is not counted as inspiration volume.
When you type in:
Base flow: on 3.0 l/min
the volume calculation in our example could be corrected.
Type the base flow parameter value in the configurator
base flow section.
Find the Correct Trigger Setting
When you set a trigger for the first time, it is important to
know the curve of the signal for the trigger (flow or
pressure). Here are some examples that also show
possible problems.
Flow Curve Downstream of the Y-Piece
Figure 39 is an example of a flow curve downstream of the
Y-piece. The standard triggers (> 3 l/min/< –3 l/min) can
be used without a problem.
gyo041.jpg
Figure 39. Downstream Flow Curve
Note
In such situations it is important to keep in mind that the
trigger is significantly higher than the noise of the base
line. Incorrect triggers can be released.
Flow Curve Upstream of the Y-Piece
The curve in Figure 40 shows the flow curve in the
inspiration duct upstream of the Y-piece. The first two
circles show the triggers that must be used here. The top
figure shows a small incorrect signal at the measurement
point after the inspiration. This is caused by switching the
valves. This results in faulty triggering.
Faulty triggering!
Time [S]
gyo042.eps
Figure 40. Inspiration Duct Upstream Curve