Helium in the treatment of respiratory failure: Why not a standard?

Abstract

The idea of replacing inspired air by helium-oxygen mixtures for treatment of acute respiratory failure is not a new one. In fact, this therapeutic approach has been proposed since the 1930s [1]. According to basic physical laws, airway resistance is dictated by airway geometry as well as by the density and viscosity of the inspired gas mixture, and the physical qualities of inspired gases cannot be dissociated from the resistive properties of the airways. Consequently, when replacing nitrogen with helium airway, resistance is reduced mainly by a substantial decrease of inspired gas density, although viscosity increases slightly. Until now, a huge number of articles has been published reporting beneficial effects of helium- oxygen breathing in patients suffering from asthma or chronic obstructive pulmonary disease (COPD), especially highlighting the improvement in respiratory mechanics [2, 3].