ABSTRACT

Not all asthmatics respond to heliox. The reason for the varying response is not clear. However, based on pathophysiology, one can expect patients with primarily small airways involvement and large amounts of retained secretions causing complete airway obstruction to be least likely to respond to heliox5. In contrast, patients with primarily large airway obstruction, where gas density determines flow, are most likely to respond. As heliox has no effect on the specific pathology of asthma, its effects are observed only during heliox use. Most responding patients demonstrate improvement within minutes when heliox is applied and demonstrate loss of effect within minutes when heliox is removed.