Demand Valve Oxygen Therapy (DVOT) is a way of delivering high flowoxygen therapy using a device that only deliversoxygen when the patient breathes in and shuts off when they breathe out. DVOT is commonly used to treat conditions such ascluster headache, which affects up to four in 1000 people (0.4%),[1][2][3] and is a recommended first aid procedure for several diving disorders.[4][5] It is also a recommended prophylactic for decompression sickness in the event of minor omitted decompression without symptoms.[5]
High flow oxygen therapy, delivered at a rate of between 7 and 15 litres per minute, has been recognized as an effective treatment for cluster headache since 1981.[6] Since then, several double-blind, randomized, placebo-controlled, crossover trials have provided further clinical evidence for its efficacy.[7][8]
A portable administration set will comprise a portable high-pressure oxygen cylinder containing sufficient gas for the expected treatment, with an oxygen service cylinder valve, an oxygen compatible first stage regulator with pressure gauge, intermediate pressure hose, and demand valve with mouthpiece.
Demand valves have been proven to be particularly effective at delivering high flow oxygen therapy.[13] Unlike conventional breathing systems, oxygen demand valves only deliver gas when the patient inhales and shut off the flow when they exhale. Exhaled gas is directed to the atmosphere through side vents. This means that almost 100 percent of the oxygen is inhaled, while the amount of exhaled carbon dioxide that the patient rebreathes is minimized.
For diving first aid anoxygen compatible diving regulator may be used if a special purpose oxygen treatment demand valve is not available.Technical divers routinely use such equipment for in-waterdecompression.
When used indiving recompression chambers and multi-place medical hyperbaric chambers, abuilt-in breathing system venting to the exterior is generally used to avoid buildup of oxygen partial pressure in the chamber to dangerous levels which would otherwise require more frequent venting.
High oxygen concentrations in the surroundings constitute a fire hazard. Oxygen therapy should be accompanied by good ventilation and avoidance of ignition sources, and where reasonably practicable, removal of combustible materials.Oxygen firebreaks are a requirement in some countries for patients usingoxygen therapy.
