Updated 1 May 2020
We have interviewed clinicians and reviewed existing ventilator standards to determine the most important alarms needed, the appropriate action to take when an alert condition is detected, and the expected behavior for silencing alarms.
- The alarm silence button should silence only the alarm tone, the visual notification should remain
- All alarms should be silenced for two minutes, even if a new alarm is triggered, the alarm silence should be maintained
- Pressing the alarm silence button again, before two minutes have elapsed should unsilence the alarms
- If multiple alarms are active, they should be visually displayed with LED’s. On the screen, the messages should cycle through.
The following table describes in detail the most important alarms identified. You are welcome to add more alarms as needed.
|Alarm Name||Detection||Clearing Condition||Tone||Response||Display Message|
|Exceeded PIP Pressure||P > Pmax = 40cmH20|
This ensures the unit can never deliver air at a pressure higher than 40 cmH20 to mitigate the risk of barotrauma (lung damage).
|One complete breathing cycle with no over pressure||Emergency Tone||Immediately stop compression, open completely, resume normal operation at start of breathing cycle||“HIGH PRESURE”|
|Under Pressure||Pplateau < Pplat_min = 5cmH20|
This alarm detects any disconnections or leaks and notifies the clinician to check the breathing tube.
|Measured plateau pressure normal||Emergency Tone||Continue normal operation||“LOW PRES DISCONNECT?”|
|High Resist Pressure||Ppip –Pplateau>Presist_max = 10cmH20|
This alarm notifies the clinician that there is unusual resistance in the breathing tube or airway.
|One resistance pressure measurement in normal range||Notify Chirp||Continue normal operation||“HIGH RESIST PRES”|
|Over Current Fault||I ≥ Imax = 4.5A|
This alarm detects the motor being pushed too hard. It indicates something may be stuck in the mechanism, or there may be a blockage in the breathing tube.
|One complete breathing cycle without an overcurrent event||Emergency Tone||Immediately stop compression, open completely, resume normal operation at start of breathing cycle||“OVER CURRENT FAULT”|
|Tidal Volume not Delivered||Vfinal<Vset – Vthres = 50mL||Delivered tidal volume in the correct range||Emergency Tone||Continue normal operation||“UNMET TIDAL VOLUME”|
|Tidal Pressure Not Detected||Ppeak – Ppeep < Ptidal-min = 5cmH20|
This alarm detects situations where the pressure does not reflect inspiration but there may not be a leak. For example, if the bag is removed from the machine.
|One complete breathing cycle without a tidal pressure failure||Emergency Tone||Continue normal operation||“NO TIDAL PRESSURE”|