What are the potential complications of using a helium inhaler?

Potential Complications of Helium Inhalers

Helium inhalers (Heliox) have limited therapeutic benefits and several potential complications, making them unsuitable for routine clinical use outside of specialized settings and clinical trials.

What is Heliox?

Heliox is a mixture of helium and oxygen, typically in ratios of 80:20 or 70:30 (helium:oxygen), that has been used in specific respiratory conditions:

• Heliox has lower density than ambient air, which can reduce resistance in large airways where flow is predominantly turbulent 1
• It's typically delivered through specialized delivery systems that maintain a gas-tight seal to prevent room air dilution 1

Potential Complications and Risks

Technical and Administration Complications

• Requires specialized delivery systems - standard oxygen masks lead to significant dilution by room air 1
• Cannot be used if patient requires >30% oxygen (the helium mixture requires at least 70% helium for therapeutic effect) 1
• Risk of inadequate oxygen delivery if not properly monitored 1
• Requires continuous monitoring to avoid technical complications 2

Direct Physical Complications

• When inhaled directly from pressurized tanks (rather than through proper medical delivery systems):
  • Risk of cerebral gas embolism, which can cause loss of consciousness, seizures, and neurological deficits 3
  • Potential for barotrauma to the lungs 4
  • Risk of pneumomediastinum from pressurized delivery 3

Clinical Limitations

• Limited evidence of clinical benefit in most respiratory conditions 1
• Does not reduce rates of intubation or length of mechanical ventilation in COPD or asthma patients 1
• No demonstrated reduction in mortality in patients with COPD or asthma 1
• Not recommended for routine use outside of clinical trials 1

Specific Clinical Applications and Complications

For Asthma Management

• Limited evidence for benefit in severe asthma exacerbations 1
• May improve delivery of nebulized bronchodilators but meta-analyses don't support its use as initial treatment 1
• Three pediatric guidelines support its use in severe asthma exacerbations, but note it should not be routinely used 1

For COPD and Hypercapnic Respiratory Failure

• A large RCT found Heliox with non-invasive ventilation did not reduce intubation rates, duration of ventilatory support, or mortality in AECOPD 1
• May temporarily reduce PaCO2 and airway pressures in intubated patients with severe asthma, but doesn't affect clinical outcomes 1

For Upper Airway Obstruction

• Most likely clinical use is for patients with mechanical upper airway obstruction or post-operative stridor 1, 5
• May provide temporary relief while definitive treatment is arranged 5, 6

Practical Considerations

• Heliox affects the delivery of aerosolized treatments in complex ways, requiring specialized nebulizer systems 1
• Heliox 80:20 mixture has similar oxygen content to air (21%) 1
• Heliox 70:30 delivers higher FiO2 but is more dense due to higher oxygen content 1
• Clinicians should aim to maintain appropriate oxygen saturation targets:
  • 94-98% for patients with asthma or upper airway obstruction 1
  • 88-92% for patients with severe COPD 1

Conclusion

Helium inhalers have specific but limited applications in clinical practice. The British Thoracic Society guidelines clearly state that "the evidence base for the use of this gas mixture is weak and the use of Heliox as an inspired gas or as the driving gas for nebuliser therapy is not recommended outside of randomised clinical trials" 1. When considering helium therapy, the risks of improper administration and limited clinical benefit must be carefully weighed against potential benefits in specific clinical scenarios.