Australian Standard 
on 
Demand Valves
A section of the Standard
Resuscitators intended for use with humans 
AS 2488-1995
 
 

As these Standards are Copyright by Standards Australia we cannot provide a copy of them here.  Legal originals with all fees paid can be purchased from us. What we have provided here is an attempt to explain some critical elements of the standards in plain English with some pictures. 
 
 

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Sections of the standard
'Australian Standard 2488-1995 Resuscitators'
intended for use with humans
 

 Note: Not all clauses are outlined only those that are topical and of interest,
 clauses such as definitions,  scope, references etc.etc. are not included.
 
Clause Outline/Key Points Comment/Discussion
5        Connectors
5.1     Patient Connectors		 The patient connection ports of a resuscitator shall have a 15mm female fitting and a 22mm male fitting.  These fittings must comply with AS 2496 Breathing Attachments for anaesthetic purposes for human use

 

 This is so that an Endotracheal Tube or similar invasive type of airway support will connect to the 15mm female as well as face masks will connect to the 22mm male fitting.
6.2      Dismantling and reassembly
             of valves		 This clause states that the device should be easily reassembled in the correct order so it will work properly.  It should not be able to be assembled incorrectly. A diagram should be provided stating number and order of assembly.

 

 This is to prevent incorrect performance. Its also important to note that valves should not be disassembled by untrained people.
6.6       Bag refill Valves Bag Refill Valves shall not have a provision for manual operation. This is to prevent a situation where the button or lever on a demand valve being used as a bag refill valve is accidentally activated and the gas flows through the valve into a Bag Valve Mask and into the patient.

 
8.1.1.2 Gas Powered resuscitators An oxygen concentration of at least 85% oxygen must be delivered

 
8.3       Expiratory Resistance The clause states a resistance of no more than 5cmH2O is allowed

Each and every single unit that leaves our workshop is tested for this.
8.4       Inspiratory Resistance The pressure shall not be below -5cmH2O Each and every single unit that leaves our workshop is tested for this.

 
8.7       Apparatus dead space The device when tested according to the correct method shall not have a dead space of more than 5ml plus 10% of the tidal volume specified for the class of the resuscitator The importance of this clause to the user is that if a resuscitator is altered via long extension tubes etc. It may be rendered as non compliant to the standard.

 
8.8.1     Tidal Volume When intended for use with children and infants  resuscitators shall be grouped according to body weight based on 15ml per Kilogram.  All devices that deliver a tidal volume of 600ml and over shall be for adults
 This makes it almost impossible to say a demand valve is compliant for a child.  Because young lungs very are fragile we will not recommend a demand valve for them.  We generally advise a manually powered child BVM be carried in all resuscitators.  All demand valves with child settings should probably be removed from service unless they are specifically designed for infants and children alone and are volume sensitive and not only flow adjustments.

8.9      Gas-powered resuscitators
8.9.1   Pressure-limiting system		 This clause states that the airway pressure shall not exceed 60cmH20. And and an audible or physical warning should occur when the pressure-limiting device activates. All units leaving our facility are individually checked for this performance.  It is one of the tests that must be carried out on a frequent basis and recorded.

 
8.9.2    Inspiratory flow Shall be capable of delivering a flow in the range of 40L/min to 60L/min against a backpressure of 2kPa when the device is activated by a trigger or button. Plus they must be able to provide at least 100L/min if the patient breaths spontaneously.

 

 This is another test that should be done frequently.  Unfortunately it requires specialised equipment.
See our section on 
Test Equipment click to jump there.


Robert Shaw

 The demand valve on the left is a Robert Shaw head which flows up to 160L/min on trigger activation. This does not meet the standard and should be replaced.  Some units are restricted to 40 L/min and as such do not meet the "on demand" element of the standard.
The unit on the right is an MTV this meets the standard and has multiple safety features above the standard requirements.  It flows at 40L/min on trigger/button activation.  It supplies 100+L/min on patient demand.

 


MTV
8.10     Demand valves
8.10.1  Pressure for initiation		 The maximum negative pressure required to initiate a gas flow shall be no more than -2cmH20
 This is another test that should be done frequently.  Every unit leaving our facility is tested for this.  The reason for this performance requirement is to ensure a patient does not have to struggle to initiate flow if they have weak inspiratory strength. Eg.  They do not have to suck to hard!

 
8.10.2  Peak inspiratory flow Minimum peak inspiratory flow when demanded by the patient, not by the operator shall be at least 100L/min when a negative pressure of -8cmH20 is applied This another test that should be done frequently.  Every unit leaving our facility is tested for this.  This standard exists to ensure a patient can get the flow they require without finding resistance at the peak portion of the inspiratory wave.
The control system on the left is designed to limit the flow for children on trigger activation.  However, not only does it not allow at least 100L/min in demand, it does not limit the tidal volume to that which is specified for children. These type of controls are used on Robert Shaw heads in some older resuscitators and as such do not comply.
8.10.3   Termination pressure The demand valve shall stop flow when the sensing device is at ambient atmospheric pressure This is to prevent a slow constant flow. This another test that should be done frequently.  Every unit leaving our facility is tested for this.

 
If you have any questions please do not hesitate to give us a call or drop us an email click here to go to our contacts page.