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Figure 8-1- Flow versus time curve in VCV mode
The operator encounters some limitations in setting high and low limits of parameters in a
ventilation mode, these limitations result from other ventilation parameters setting. these
limitations are defined to meet the following conditions:
Ti should not be less than 100 ms and less than 10% of the respiratory cycle time.
Pause time is considered a part of Ti.
However, the part of the Ti that remains after
reducing the pause time should not be less than 100 ms.
Ti should not be greater than 5s and greatern than 80% of the respiratory cycle time.
Te should not be less than 200 ms and 20% of the respiratory cycle time.
In volume based modes with a square flow pattern, the device delivers the user's adjustable
volume to the patient with a constant amount of flow during the inhalation time.
Note:
While Vt, Rate, Pause and Ti parameters are changed by the user, Flow and Pause time will
be displayed on the screen.
It should be noted that if Compliance Compensation and Leak
Compensation are desabled, the deliverd flow may be different from the flow displayed on
this menue.
Adjustable parameters in VCV mode are:
Definition
Parameter
Percentage of delivered oxygen to the patient
2
O
Mandatory breaths per minute
Rate
Tidal volume delivered during inspiration
t
V
Positive end expiratory pressure
PEEP
Inspiratory time
Ti
The method of detecting the patient's respiratory effort (flow or pressure).
Trigger
Threshold of detecting patient respiratory effort based on flow or pressure
F Trig/ P Trig
Percentage of inhalation time after which the current volume is delivered,
respiration remains in the inhalation and then exhalation begins. During this
period, no volume is transferred to the patient.
Pause
the pattern of applied flow to the patient
Flow Pat.
If the patient tries to breathe during inhalation, the device responds to this
request by switching on the pressure control
Dual control
