Replace old Draeger APL valves

The Draeger anaesthetic machine has a poorly understood issue with its APL valve. When lifted it is actually open – even though it appears closed – creating an inability to pressurise the breathing circuit.


It can be jammed open (see valve on right above) particularly when the gas sample line becomes trapped underneath. In turn patients can’t be ventilated – anaesthetists are often unable to diagnose the cause placing patients at unnecessary risk.

Draeger know about this problem and have introduced a bevelled APL valve on newer anaesthetic machines (see valve on right below):


There are numerous anaesthetic machines being used with the old hazardous APL valve. The new beveled APL valve can be retro-fixed onto older machines – we should ensure this is done.

Sign the petition to promote the recall of old Draeger APL valves.

Numerous episodes of APL trapping have been reported in the literature:

1. Gas leak related to Draeger Primus Anaesthetic Machine. Anaesthesia, July 2010.

2. Cable trapped under Drager Fabius automatic pressure limiting valve causes inability to ventilate. Anesthesiology, March 2007.

3. Wires block APL valve interfering with ventilation. APSF newsletter Summer 2011.

4. Failure of ventilation due to trapped gas sample line in the adjustable pressure limit (APL) valve. BJA, April 2010.

5. Draeger APL valve. FDA – Adverse Event Report. Sept 2012.

6. A potential hazard involving the gas sampling line and the adjustable pressure limiting valve on the Drager Apollo Anesthesia Workstation. Anesthesia & Analgesia. August 2010

7. Temporary malfunction of an APL valve. BJA, March 2006.

8. Massive Leak During Manual Ventilation: Adjustable Pressure Limiting Valve Malfunction Not Detected by Pre-Anesthetic Checkout. Anesthesia & Analgesia. August 2010.

9. Failure to Ventilate with the Drager Apollo Anesthesia Workstation. Anesthesiology, March 2011.

10. Apollo Anesthesia Workplace. FDA – Adverse Event Report. Sept 2012.

11. Accidentally opened adjustable pressure-limiting valve. Failure of manual ventilation. Anaesthesist, March 2009

12. Drager Apollo Anesthesia Workstation APL Valve on Workstation. FDA Adverse Event Report. Sept 2014.

13. Cable Trapped Under Dräger Fabius Automatic Pressure Limiting Valve Causes Inability to Ventilate. Anesthesiology, March 2007.

14. A Malfunction of the APL Valve (in German). Anästh Intensivmed, Feb 2011.

15. Circuit leak from capnograph sampling line lodged underneath adjustable pressure limiting valve. Anaesthesia and Analgesia, August 2010.

16. Page 29 of Anaesthesia News. June 2012.

17. MAUDE report (despite sample line being clipped away) Sept 2012

In all of these cases the reporting anaesthetist is caught unaware – this is despite alerts (see below) demonstrating the inefficiency of alerts on their own as a safety solution. Still many anaesthetists are unaware of this problem.


The function of the APL valve being open when elevated is unique to Draeger machines. It is not a function intuitive to the majority of anaesthetists.

The case reports above represent only a fraction of the actual events. The author  is aware of numerous other cases not  reported here.

Several similar events have been reported to the FDA. We’re suspicious they may be due to APL trapping – there’s an inability to pressurise the circuit with manual ventilation mode on induction, in some instances being able to with mechanical modes which bypass the APL valve.

1. Draeger Medical AG KGAA Anesthesia Machine. Adverse Event Report. July 2006.

2. Primus Anaesthesia Unit. Permanent brain injury. Adverse Event Report. April 2013.

3. ‘Could not ventilate in manual mode but automatic mode ventilation worked as expected’. Adverse Event Report. June 2015.

4. ‘No positive pressure ventilation could be achieved in manual/spontaneous mode. Automatic ventilation worked as expected’. July 2011.

5. Patient became hypoxic, hypotensive and bradycardic. July 2011.

6. ‘The user almost lost the patient’. February 2009.

7. Unable to deliver gas flow on induction – however issue seems to exist in automatic mode also. Investigation ongoing. October 2013.

8. Significant circuit leak. January 2013.

9. ‘After uneventful induction…unable to apply O2 flush or breathing pressure to the patient’. January 2008.

We reported this issue on 12.2.2016 to the TGA – report #40091. Responses from Draeger (see below) and the TGA (see here) have so far been unproductive – we will continue to pursue this issue.

To our knowledge there are 78 of the old APL valves in Australia, unfortunately we don’t know where they are. They would cost Draeger approximately $350 each to replace.

We should ensure these old APL valves are replaced in the interest of patient safety.

Sign the petition to promote the recall of old Draeger APL valves.

APL valve open left (notice gap at base of valve)
APL valve on right open (notice gap) despite appearing closed
Gas sample line trapped (left).  Newer bevelled APL valve (right)

Letter from Draeger 26th July 2016:


6 thoughts on “Replace old Draeger APL valves

  1. Hi Patientsafe,

    We appreciate your interest in the community’s safety, which we, too, hold it in high regard. Please know the Dräger team has been fully aware of this topic. We improved the user friendliness of this specific valve design already in 2010 in all our new machines. Since then and until today we continue to offer customers upgrades to their devices with the new APL valves. Please contact Dräger Service if you require support.


    1. Perhaps the title should be “Replace all Draeger Machines”?
      Had a nasty episode myself and they are generally unreliable compared
      To the usual alternatives .


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