Is heliox used to treat acute asthma exacerbations?

Heliox in the Treatment of Asthma

Heliox is not recommended for routine use in acute asthma exacerbations and should be restricted to clinical trials or exceptional circumstances under specialist supervision. 1, 2

Current Guidelines on Heliox Use

The British Thoracic Society (BTS) guidelines provide clear recommendations regarding heliox use in respiratory conditions:

• There is insufficient evidence to support the routine use of heliox in patients with acute exacerbations of asthma 1
• Heliox should only be considered in clinical trials or in specialist hands for severe asthma exacerbations that are not responding to standard treatment 1, 2
• The strongest evidence for heliox benefit exists for mechanical upper airway obstruction or postoperative stridor, not for asthma 2

Evidence Analysis

The evidence against routine heliox use in asthma is substantial:

• Cochrane systematic review found no significant improvement in pulmonary function tests when pooling data from eight trials 3
• Meta-analyses have concluded that heliox does not affect important clinical outcomes in asthma 2
• Even in severe exacerbations, heliox has not been shown to reduce mortality or need for mechanical ventilation 2

While some studies suggest potential benefits in specific scenarios:

• Patients with the most severe baseline pulmonary function impairment may show some improvement, but this is based on a small number of studies 3
• One older study (1995) showed improvements in pulsus paradoxus and peak expiratory flow in non-intubated patients with severe asthma 4, but these findings have not translated to meaningful clinical outcomes in larger trials

Practical Limitations

Several practical issues further limit heliox utility:

• Higher cost compared to standard oxygen-air mixtures 2
• At oxygen concentrations >40%, heliox loses its theoretical advantages due to increased gas density 2
• Technical challenges in administration, including room air entrainment during beta-agonist delivery, which can negate the beneficial effects of heliox 5

Clinical Application

For patients with acute asthma exacerbations:

1. Standard treatment should be prioritized:

   • Beta-agonists
   • Systemic corticosteroids
   • Oxygen therapy as needed

2. Heliox should only be considered when:

   • Patient has severe asthma not responding to standard treatments
   • Specialist supervision is available
   • Patient is enrolled in a clinical trial
   • There are contraindications to intubation in a deteriorating patient

Bottom Line

The current evidence and guidelines do not support the routine use of heliox in the management of acute asthma exacerbations. While it may have theoretical benefits in reducing airway resistance due to its lower density, these have not translated to clinically significant improvements in patient outcomes. Standard asthma treatments remain the cornerstone of therapy.