C-14 624074/07
CASV
®
(Adaptive Support Ventilation)
Step 7: Weaning
Weaning patients from the ventilator is a clinical task that
requires significant experience, and involves more than just
ventilation issues. Important: This appendix does not intend to
provide clinical information other than what is needed to oper-
ate the ventilator with ASV.
ASV always allows patients to take spontaneous breaths. Epi-
sodes of spontaneous breathing can occur and are supported
by ASV even within a period of fully controlled ventilation.
Actually, weaning can begin with ASV at an early point that it
could go unrecognized clinically. Therefore it is important to
monitor the spontaneous efforts of the patient over time.
The weaning progress can be monitored in the Trends display
when inspiratory pressure (Pinsp), total rate (fTotal), and spon-
taneous rate (fSpont) are plotted. If the patient tolerates mini-
mum respiratory support after a period of time with
Pinsp < 8 cmH2O, fControl = 0
weaning can be considered achieved, if minimum
fSpont is acceptable and ExpMinVol is acceptable
What is “acceptable” must be defined by the clinician.
It can be necessary to reduce the %MinVol setting to 70% or
even lower to “motivate” the patient to resume spontaneous
breathing.
If a patient can sustain minutes or even hours with a low
%MinVol setting, this does not mean weaning is complete. In
fact, the %MinVol setting must always be interpreted in con-
junction with the level of Pinsp needed to achieve the set min-
ute ventilation. Only if Pinsp and fControl are at their minimal
values can weaning be assumed to be complete.
To Next Page
Loading...