Medical gas therapy

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Medical gas therapy
Other namesTherapeutic gas
Specialtypulmonology
gaseous signaling molecules

Medical gas therapy is a treatment involving the administration of various gases. It has been used in medicine since the use of oxygen therapy.[1] Many other gases, collectively known as factitious airs, were explored for medicinal value in the late eighteenth century.

Nitric oxide

See also: Biological functions of nitric oxide § Vasodilation and smooth muscles

premature infants.[1]

Helium and oxygen

In medicine,

air
) and 79% He, although other combinations are available.

Heliox generates less airway resistance than air and thereby requires less mechanical energy to ventilate the lungs.[3] "Work of Breathing" (WOB) is reduced. It does this by two mechanisms:

  1. increased tendency to laminar flow;
  2. reduced resistance in
    turbulent flow
    .

Heliox has a similar

turbulent flow. The tendency for each type of flow is described by the Reynolds number. Heliox's low density produces a lower Reynolds number and hence higher probability of laminar flow for any given airway. Laminar flow
tends to generate less resistance than turbulent flow.

In the small airways where flow is laminar, resistance is proportional to gas viscosity and is not related to density and so heliox has little effect. The Hagen–Poiseuille equation describes laminar resistance. In the large airways where flow is turbulent, resistance is proportional to density, so heliox has a significant effect.

Heliox has been used medically since the early 1930s. It was the mainstay of treatment in acute

bronchodilators. Currently, heliox is mainly used in conditions of large airway narrowing (upper airway obstruction from tumors or foreign bodies and vocal cord dysfunction). There is also some use of heliox in conditions of the medium airways (croup, asthma and chronic obstructive pulmonary disease
).

Patients with these conditions may develop a range of symptoms including

anaesthesia.[6]

References

  1. ^
    PMID 10450191
    .
  2. S2CID 34231129
    .
  3. ^ "Heliox21". Linde Gas Therapeutics. 27 January 2009. Retrieved 13 April 2011.
  4. ^ BOC Medical. "Heliox data sheet" (PDF).
  5. PMID 16141015
    . Retrieved 2008-07-08.
  6. PMID 16143576
    .
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