Résumé
First described in the 1930s', there is a good theoretical rationale for using helium as an adjuvant treatment in the respiratory care of patients with severe airway obstruction. Pure helium has been replaced in clinical practice by "helium-oxygen'' mixtures that are safer to use. Helium has no pharmacological effect. The physical properties of this light, single-element gas allow mechanical and physiological effects on the respiratory system that can be used in asthma and chronic obstructive pulmonary disease patients. Helium-oxygen can be used in different conditions (e.g. spontaneous ventilation, noninvasive ventilation (NIV) or mechanical ventilation) and with different aims (to increase drug delivery in bronchodilator aerosols, to decrease work of breathing, and to decrease ventilation pressures and air trapping during mechanical ventilation). The clinical success of helium treatment probably depends on technical conditions and devices. In the absence of adapted medical devices it is often used only as a last resort in critical patients. With more information, adapted equipment and experienced intensive care unit teams, more patients could potentially benefit from this very old therapeutic gas.