C-10 624074/07
CASV
®
(Adaptive Support Ventilation)
The high ventilation moves the minimum minute volume curve
to the right while the obstructive disease causes the safety limit
of rate to shift to the left. These two effects cause the minute
volume curve to lie outside the safety limits as determined by
the lung-protective rules strategy (see functional description
below). ASV thus chooses the safest point closest to the opera-
tor-set minute volume.
Figure C-3. Hypothetical example of high %MinVol set-
ting incompatible with the lung-protective rules strategy.
The open circle denotes the actual target, the closed triangle
(never shown on the ventilator) denotes the (energetically)
optimal target according to Otis’ equation. The device will
alarm and inform the operator that the ASV target cannot
be achieved.
Step 6: Monitoring ASV
ASV interacts continuously with the patient. Whenever the
patient’s respiratory mechanics change, ASV adapts to this
change. Whenever the patient’s breathing activity changes,
ASV adapts. To view the current status, the device provides the
ASV target graphics window (Figure C-4) and the ASV moni-
tored data window (Figure C-5).
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