Triggering With Valve Circuits - ResMed Astral Series Clinical Manual

Triggering with valve circuits

When using single or double limb valve circuits, the Astral device uses ResMed's NIV+ trigger sensitivity
technology. Unlike simple conventional triggering which only considers the magnitude of the pressure
change, NIV+ also considers the shape of the pressure waveform to significantly improve trigger
sensitivity.
Pressure trigger with single and double limb circuits
The Astral device is able to detect a negative change of pressure, relative to the pressure base line at the
end of expiration, indicating the start of a patient spontaneous breath. There are five sensitivity levels of
trigger sensitivity from Very Low to Very High.
Flow trigger with double limb circuits
Flow triggering is suitable for use with double limb circuits for invasive applications with no expected
leak eg, cuffed tracheostomy. By monitoring the exhaled gas, the Astral device is able to detect an
increase in patient respiratory flow at the end of expiration, indicating the start of a spontaneous breath.
The flow trigger threshold represents the increase in patient respiratory flow at the end of expiration.
When that threshold is reached the device starts the inspiratory phase.
Flow trigger range
Adult:
Paediatric:
The lower the setting number, the higher the sensitivity.
L/min
0.5-15 [Default = 1.0]
0.5-15 [Default = 0.5]
Ventilation modes
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