Therapeutic use of the helium-oxygene mixture in pulmonary medicine.

Therapeutic use of the helium-oxygene mixture (heliox) was first reported i n 1934. Medical use was further restricted to physiological studies. Densit y and viscosity of Heliox are very different from those of air or oxygene. This can explain how Heliox can induce modifications in the airway flow. In diseases of the main or small airways (upper airway obstruction, chronic o bstructive pulmonary disease, asthma), such modifications could induce a di minution in the resistive component of the work of breathing and therefore protect against the risk of developing a respiratory failure. This explains a renewed interest of clinicians for Heliox since the beginning of the eig hties. To date, the good tolerance of heliox seems to be well established. Inversely, scientific validation of the therapeutic indications of the mixt ure in airway diseases are lacking. Moreover, potential therapeutic indicat ions of the mixture are not restricted to airway diseases. Various applicat ions, such as adult respiratory distress syndrome,, pneumothorax, fiberopti c bronchoscopy, and mechanical ventilation, are suggested by preliminary re ports. Obtaining a synthetic vision of older and more recent studies is the purpose of this review.