This code system http://hl7.org/fhir/device-operation-status-reason defines the following codes:

Code Display Definition
3::6728 Check air supply Checking of ventilator air supply is necessary.
3::6678 Battery needs replacement Advisory: Replace Battery (a full charge is now a too small fraction of the original capacity or this is not a rechargeable battery that is close to empty.)
3::462 CO2 failure Failure occurred in a CO2 measuring device
3::6708 Time adjustment check Advisory: Check time (system asks user to check the time)
3::694 Patient ID change Advisory: The ID of the patient connected to the device has changed
3::724 Infusion volume complete Advisory: Infusion of the specified volume has been completed
3::120 Unplugged A component (sensor, module) has become unplugged
3::132 Inoperable Device has become inoperable
3::410 Alarm limit Alarm limit exceeded
<status value="active"/> <experimental value="false"/> <date value="2020-12-28T16:55:11+11:00"/> <publisher value="HL7 (FHIR Project)"/> <contact> <telecom> <system value="url"/> <value value="http://hl7.org/fhir"/> </telecom> <telecom> <system value="email"/> <value value="fhir@lists.hl7.org"/> </telecom> </contact> <description value="The availability status reason of the device."/> <jurisdiction> <coding> <system value="http://unstats.un.org/unsd/methods/m49/m49.htm"/> <code value="001"/> <display value="World"/> </coding> </jurisdiction> <caseSensitive value="true"/> <valueSet value="http://hl7.org/fhir/ValueSet/device-operation-status-reason"/> <content value="complete"/> <concept> <code value="3::6728"/> <display value="Check air supply"/> <definition value="Checking of ventilator air supply is necessary."/> </concept> <concept> <code value="3::6678"/> <display value="Battery needs replacement"/> <definition value="Advisory: Replace Battery (a full charge is now a too small fraction of the original capacity or this is not a rechargeable battery that is close to empty.)"/> </concept> <concept> <code value="3::462"/> <display value="CO2 failure"/> <definition value="Failure occurred in a CO2 measuring device"/> </concept> <concept> <code value="3::6708"/> <display value="Time adjustment check"/> <definition value="Advisory: Check time (system asks user to check the time)"/> </concept> <concept> <code value="3::694"/> <display value="Patient ID change"/> <definition value="Advisory: The ID of the patient connected to the device has changed"/> </concept> <concept> <code value="3::724"/> <display value="Infusion volume complete"/> <definition value="Advisory: Infusion of the specified volume has been completed"/> </concept> <concept> <code value="3::120"/> <display value="Unplugged"/> <definition value="A component (sensor, module) has become unplugged"/> </concept> <concept> <code value="3::132"/> <display value="Inoperable"/> <definition value="Device has become inoperable"/> </concept> <concept> <code value="3::410"/> <display value="Alarm limit"/> <definition value="Alarm limit exceeded"/> </concept> </CodeSystem>