A demand valve, also known as a ventilation demand valve or oxygen demand valve, is a valve that allows the flow of gas – air or oxygen – only when a change in pressure occurs that indicates a demand. This means that the gas is only released when a demand is signaled by the pressure change in the patient’s inspiration or the filling of a ventilation bag after the expulsion phase. Just “ON DEMAND“
Using a membrane, the demand valve detects a negative pressure at the outlet to the patient (mask) or to the ventilation bag. The negative pressure (approx. 0.5 mbar) is created when the patient breathes in or the ventilation bag is sucked in. This triggers the demand valve to open and the patient is supplied with oxygen or air. If the negative pressure falls below the response threshold, the valve closes again (compression of the ventilation bag ends or the patient no longer breathes in).
A further advantage of using a demand valve during ventilation with a ventilation bag, in contrast to a reservoir bag supplied by constant flow, is that the patient can be supplied with 100% pure oxygen, which significantly increases the effectiveness of ventilation (oxygen supply and gas exchange). When using a reservoir bag, only a maximum O2 enrichment of up to 84% O2 is possible due to the additional intake of ambient air.
The main areas of application for demand valves are in the fields of anesthesia / pain therapy / dentistry / emergency services.
But our demand valves can do even more: in the demand valve version with manual ventilation function (QualityFLOW MTV), in addition to the normal function of supplying gas “on demand”, manual ventilation is also possible at the touch of a button without a resuscitation bag in the demand valve MTV version.
Demand valves are also suitable for the administration of nitrous oxide as required. With our QualityFLOW N2O, we offer a special version with integrated respiratory gas discharge (expiratory) for this purpose. This prevents enrichment of the ambient air with nitrous oxide.
In conjunction with our nitrous oxide/oxygen mixers from the QualityMix family, the valve can be used both with a directly connected mask and in conjunction with a breathing tube.
A ventilation bag (Ruben bag), also known as a manual resuscitation bag or self-inflation bag, is a device used to manually ventilate patients who cannot breathe on their own. Here is a description of how an Ambu bag works:
Ventilation bags are an essential part of emergency equipment in hospitals, ambulances and for first responders. They enable effective and life-saving ventilation in situations where patients cannot breathe on their own.