Puritan Bennett 840 Troubleshooting

Either the LOW BATTERY alarm or INOPERATIVE BATTERY alarm is active. They possibly remain active during charge.

The backup power service (BPS) provides power to the ventilator when the AC power drops below a certain level. The BPS is recharged during normal operation. Ensure that the ventilator itself is not unplugged, and that it has not been unplugged for an extended period of time. If so, make sure the BPS is connected to an operating ventilator for up to eight hours to recharge it.

If the alarm will not go off after these steps have been taken, the BPS battery might need to be replaced. See our BPS battery replacement guide here.

The compressor or humidifier seem to be inoperative or unresponsive.

The backup power service (BPS) is intended for short-term power in the event that the ventilator loses AC power. It is not a primary power source, therefore it is only intended to power the breath delivery unit (BDU) and graphical user interface (GUI). Ensure that the ventilator is connected to an AC power source and that it is not running solely off of the BPS.

Ensure that the gas source to the compressor is connected and free of water, particles, and lubricant.

When changing either the humidifier type or patient circuit, a short self test (SST) must be performed. Do not use the “gold standard” circuit. DO NOT PERFORM THIS TEST WHILE THE PATIENT IS CONNECTED TO THE VENTILATOR.

To perform a SST, press SST at the Ventilator Startup Screen. Within five seconds, press TEST on the side of the ventilator. At the SST Setup Screen, specify the patient circuit and humidifier types, then press ACCEPT. You may be prompted to fill the humidifier with water and connect. Once you have followed all of the prompts, the SST will complete itself. You may halt testing at any time by pressing EXIT SST. Press EXIT SST again to resume. At the completion of the test, press ACCEPT after pressing EXIT SST to restart the ventilator.

After running a short self test, the result is FAILURE or ALERT.

If the ventilator returns ALERT as a result, it indicates that the SST result for a specific module is not critical, but not recommended.

If the ventilator returns FAILURE as a result, the SST result for a specific module is critical and no further testing can occur until the FAILURE is cleared.

Once the SST has tested all of the modules, it will return an overall result. If the overall result returns ALERT, then one or more faults were discovered during the testing process. However, these can be overridden if deemed safe by pressing OVERRIDE > ACCEPT > EXIT SST > ACCEPT to begin regular ventilation.

If the overall result returns FAILURE, the faults that were detected are critical and cannot be overridden. The ventilator cannot proceed to regular ventilation until the critical faults have been addressed through service.

The patient circuit involves the tubing system running to and from the patient. If the circuit does not fall within the ideal testing specifications, the SST result may be faulty. To verify the specifications of your patient circuit, see page OP A-18 in the Operator’s and Technical Reference Manual here.

When using a drain bag, the tubing that connects the collection vial drain to the drain bag must be properly installed. The drain bag tubing should be clamped. If the tubing is not clamped properly, leaks may cause discrepancies during the SST process to occur. If large amounts of leakage are detected during the SST, the Circuit Leak Test SST will fail. Check to see that the drain bag tubing is clamped and properly connected.

Many times during this test module, the ventilator may return an ALERT result. However, it may be crucial to not override this ALERT as it may produce inexact pressure readings for the patient. Ensure that the tubing is properly detached from the expiratory filter. Reattach the tubing, then detach it, and then press ACCEPT to restart the test.

If the Expiratory Filter Resistance SST Test result is a FAILURE, there is a critical exhalation compartment occlusion or an expiratory filter occlusion. Inspect both the exhalation compartment and expiratory filter if possible. The expiratory filter may have to be replaced. If this is the case, see our expiratory filter replacement guide here.

Another cause of FAILURE is if the patient circuit was not attached properly. This will be known because the ventilator will prompt the user to reattach the patient circuit. To proceed, reattach the patient circuit and press ACCEPT to restart the test.

The ventilator’s oxygen monitoring feature is missing or seems to be malfunctioning.

The oxygen monitoring feature is always enabled at power-up by default. However, it can be disabled. To check whether or not this setting is enabled, locate the following on the lower touch screen: OTHER SCREENS -> MORE SETTINGS. Once you have enabled the oxygen sensor, press ACCEPT.

If the oxygen monitoring feature is enabled in settings and any effort to restore its functionality fails, then the oxygen sensor may be faulty. Typically, you will see the O2 SENSOR alarm, indicating the need to calibrate or replace the sensor. The oxygen sensor may be calibrated by pressing the 100% O2/CAL 2 MIN key and waiting for two minutes. If no changes result, see our oxygen sensor replacement guide here.

Upon connecting a patient to the ventilator, the ventilator refuses to function or declares an error.

If a patient is attached before the patient setup process is complete, the ventilator will begin safety ventilation and the PROCEDURE ERROR alarm will go off. The patient setup process begins after turning on the ventilator, or after running a short self test (SST). On the ventilator startup screen, either select SAME PATIENT to continue ventilating with previous settings, or NEW PATIENT to begin calibrating new settings.

If you selected NEW PATIENT, you must change the settings in the IBW menu before pressing CONTINUE. When all settings are adjusted, put them into effect by pressing ACCEPT. The oxygen sensor may be calibrated by pressing the 100% O2/CAL 2 MIN key and waiting for two minutes.

Ventilation will only begin if the ventilator senses a patient attached. Check the connections in your patient circuit to make sure nothing is disconnected. To check the patient circuit for leaks, run a short self test (SST). See “Humidifier Must Be Calibrated” above for SST instructions. DO NOT RUN A SST WHILE THE PATIENT IS CONNECTED.

If the TEST button is pressed while powering on the ventilator, the ventilator will go into Service Mode. The display will have different options. To exit Service Mode, press the EXIT button on the lower touch screen, then press ACCEPT.

Inspiratory or expiratory pause maneuvers are not behaving as specified or do not appear to be working.

If the patient triggers breaths during the waiting period prior to the start of the Expiratory Pause maneuver, the ventilator will wait approximately one minute while it detects the appropriate conditions to start the maneuver. If the conditions are not met during the wait period, the ventilator cancels the pause maneuver. Consider switching from automatic pauses to manual.

If the patient initiates a breath or an alarm occurs during the Expiratory Pause maneuver, the ventilator cancels the maneuver, and returns to normal ventilation. Consider switching from automatic pauses to manual.

If the ventilator detects a patient circuit disconnect, the ventilator enters idle mode and pause maneuvers are cancelled. Restart automatic or manual inspiratory and expiratory pauses.

For all invalid results, check the patient-ventilator interaction, the breathing waveforms, and the patient circuit. Check for insufficient expiratory interval, and if possible, shorten inspiration time and reduce respiratory rate. If the plateau is unstable, check the circuit for moisture condensation or movement.

Asterisks (******) mean variables fall below noise-level bounds. This indicates ruptured filters that need to be discarded and replaced. See our expiratory filter replacement guide here.

Flashing Cstat or Rstat values are out of bounds. This can indicate occlusion. In this case, you can change the ventilator settings and/or replace the filter with our expiratory filter replacement guide above as well.

The safety valve alarm will not turn off, even if the oxygen is running.

First, try simply pressing the TEST button on the side of the ventilator. If this does not work, running a successful EST will silence the safety valve alarm. To run this test, ensure you have full AC power, and air and oxygen supplies, then press TEST while powering on the ventilator. This will cause the ventilator to go into Service Mode. On the lower touch screen, press EST. This test must be run with the “gold standard” test circuit, or it may fail. WARNING: If the EST fails once, the ventilator will remain inoperative until a successful EST is passed.

While the ventilator is performing its tests, you may have to provide input. You may halt testing at any time by pressing EXIT EST, and pressing EXIT EST once more to resume. If the test is successful, press ACCEPT after pressing EXIT EST to begin ventilation. To exit Service Mode, see “Ventilator Is in Service Mode” above.