The Passive circuit provides leak compensation. When using the Passive circuit in Volume Ventilation, the set Vti is delivered to the patient above the calculated circuit and cuff (or mask) leak. This is different from traditional active circuit ventilation where the cuff (or mask) leak reduces the tidal volume delivered to the patient. Volume ventilation with the Passive circuit delivers an inspiratory tidal volume close to the device setting regardless of leak; this should be considered when transitioning a patient from an active to a passive circuit. With a Passive circuit, Vte is estimated based on the calculated sum of circuit and cuff (or mask) leak.
The Active Flow circuit monitors proximal flow and proximal pressure. When using the Active Flow circuit configuration, flow trigger with leak compensation may be enabled. The default setting when using the Active Flow Circuit is Leak Compensation On. The clinician has the option to turn off leak compensation; however, unintentional leak will not be compensated. Both options measure the flow at the proximal flow sensor. Leak compensation is not available in the Active with PAP circuit configuration.
Circuit Disconnect
This setting enables or disables the circuit disconnect alarm. If enabled, an audible alarm will sound when a large, continuous air leak (such as mask removal) has been detected in the circuit.
You can choose Off to disable the alarm. Or, you can increase or decrease the setting from 5 to 60 seconds in 5 second increments. For example, a setting of 10 means that the alarm will sound after the circuit has been disconnected for 10 seconds.
Apnea
This setting enables or disables the apnea alarm. If enabled, an audible alarm will sound when an apnea is detected.
You can choose Off to disable the alarm. Or, you can increase or decrease the setting from 10 to 60 seconds in 5 second increments. For example, a setting of 10 means that the alarm will sound if the time between spontaneous breaths exceeds 10 seconds.
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WARNING
You should not rely on any single alarm to detect a circuit disconnect condition. The Low Tidal Volume, Low Minute Ventilation, Low Respiratory Rate, and Apnea alarms should be used in conjunction with the Circuit Disconnect alarm.
Chapter 5 Viewing and Changing Settings
