Learn Circuit - ResMed Astral Series User Manual

Assembling patient circuits

Learn Circuit

In order to support a wide range of circuit configurations and accessories, the Astral device provides a
Learn Circuit function to determine the characteristics of the circuit. As part of the Learn Circuit
functionality the Astral performs a device self-test and a calibration of the FiO
CAUTION
To ensure optimum and accurate performance, it is recommended that the Learn Circuit function
be performed with every change of circuit configuration and at regular intervals not less than once
every three months.
Do not connect patient interfaces prior to performing the Learn Circuit. Patient interfaces include any
components placed after the single circuit's expiratory valve or exhalation port, or double limb circuit's 'Y'
piece (eg, HMEF, catheter mount, mask, tracheostomy tube).
To perform a Learn Circuit:
1. From the Setup main menu, select the Circuit sub-menu.
2. Press Start and follow the on-screen prompts.
Note: Trigger type sets whether a pressure-based or flow-based trigger threshold is used when a Double circuit
is selected.
The prompts will guide you through a number of steps including:
With the patient interface disconnected from the patient connection port, the Astral device will
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characterise the impedance of the inspiratory path.
With the patient connection port sealed, the Astral device will characterise the total circuit
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compliance, and then the impedance of the expiratory path.
After completing these steps, a test result screen is displayed. You can access this Results screen
later using the Results button in the Circuit setting up screen.
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sensor (if installed).
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