Helium-oxygen mixture for treatment in upper airway obstruction; a mini-review

In the 1930's Alan Barach introduced helium in combination with oxygen, heliox, to the medical world. He found that helium's physical properties help reduce the work of breathing, reduce airway resistance, and subsequently improve alveolar ventilation in obstructed airways. In the presence of airway narrowing, heliox has the benefits of increasing the tendency to laminar flow (which has lower resistance) and reducing resistance when turbulent flow occurs. Heliox, a helium-oxygen mixture, has since been used sporadically and only scattered reports are found on its use for treatment in patients with upper airway obstruction. The aim of the present review was to search and review the available evidence for its safe and effective clinical use. A total of 20 publications about the use of helium-containing gas mixture for the treatment of upper airway obstruction in adults were found in the search of public domain literature. Most case reports describe short-term beneficial effects, temporarily improving breathing and oxygenation. Authors of the case reports suggest helium-oxygen mixture as an optional bridge, while a more definite treatment takes action. There are, however, no prospective randomized controlled studies and thus there is lack of high-quality proof supporting its safe and efficacious use. In conclusion, the physiochemical properties promoting laminar flow in restricted airways and the sparse but still seemingly positive clinical experience favor the use of helium-oxygen mixture as a symptomatic rescue therapy. The risk for side effects, apart from the reduced oxygen concentration in the inspired gas, seems minor. There is, however, still a lack of evidence to support the general use of oxygen-helium mixture for upper airway compromise due to the sparse information available. Further studies, although not easily designed, are warranted.