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2.4 PSV
Pressure Supported Ventilation
This is a pressure limited mode of ventilation in which each breath is patient triggered and
supported. The breath is patient triggered, pressure supported and patient terminated. The
infant therefore has control of the whole cycle, i.e. the inspiratory time, frequency and minute
volume. This form of ventilation is dependant on the use of a flow sensor placed between the
ET tube connector and the patient circuit. Changes in flow or volume signal detects
spontaneous breathing.
The termination sensitivity is also user adjustable from 0% - 50%. 5% termination sensitivity
means that 95% of the peak flow has been achieved. Pressure support can be manually
adjusted by use of the PIP parameter control.
Note: If the user sets the termination sensitivity to OFF the PSV mode
behaves as PTV.
PSV can be used in the weaning process. Weaning is achieved by reducing the support
level as the infant is able to make more effort.
In this mode all the patient's breath attempts are pressure supported, but mechanical
breaths are delivered at the set parameters (Ti, PEEP and PIP) when a patient effort is
recognised.
The User sets the following:-
• Positive End Expired Pressure (PEEP)
• Peak Inspiratory Pressure (PIP)
• Inspiratory Time (Ti)
• Backup breath rate (Backup)
• The flow termination sensitivity
• Apnoea Time (Only if backup breath rate is 19 breaths per minute or lower)
•Fi0
2
• Flow breath detection threshold (Set Trigger) - The patient effort required to satisfy
the apnoea alarm.
• High and low pressure alarm thresholds
• Tidal volume, high and low alarm thresholds
• Minute volume, high and low alarm thresholds
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