Respiratory controversies in the critical care setting. Should heliox be used for mechanically ventilated patients?

Helium is an inert gas with a very low density (0.18 g/L), which allows it to pass through narrowed passages with less turbulence than nitrogen or oxygen. For many years, helium-oxygen mixture (heliox) has been used for patients with severe airway obstruction. However, the data supporting the clinical application of heliox are few and clearly nondefinitive. This article reviews the medical literature on whether heliox should be used for mechanically ventilated patients. No definitive randomized studies have attempted to answer this question. Studies both support and contest the benefit of heliox during mechanical ventilation. Most studies agree that heliox is extremely safe; no adverse effects have been reported. However, heliox must be administered with vigilance and continuous monitoring to avoid technical complications. As is the case with all therapies that have not been definitively studied, the risk/benefit ratio for an individual patient must be assessed by the clinical care team.