How do I manage a patient requiring interface with heliox?

Managing Heliox Interface in Clinical Practice

Heliox must be delivered via a gas-tight sealed system (non-rebreather mask with reservoir or tight-fitting face mask) to prevent room air dilution, which significantly compromises therapeutic efficacy. 1

Primary Clinical Indication

The most appropriate use of heliox in clinical practice is for mechanical upper airway obstruction or postoperative stridor, where the reduced gas density can decrease airflow resistance and work of breathing. 1, 2 This represents the strongest indication, as lower airway diseases (asthma, COPD) lack definitive evidence of mortality or morbidity benefit. 1, 2, 3

Critical Interface Requirements

Delivery System Selection

• Standard high-concentration reservoir masks are inadequate because they allow significant room air dilution, rendering heliox ineffective. 1
• Use only systems that achieve a complete gas-tight seal with no leaks between the delivery device and surroundings. 1, 3
• Specialized delivery systems are mandatory for therapeutic effect. 2, 3

Mixture Selection Based on Clinical Need

For predominantly hypercarbic patients:

• Use Heliox 80:20 (80% helium, 20% oxygen), which has oxygen content similar to room air (21%). 1, 3, 4
• This maximizes the density reduction benefit while maintaining adequate oxygenation. 4

For hypoxemic patients:

• Use Heliox 70:30 (70% helium, 30% oxygen) to deliver higher FiO2. 1, 3
• Note that this mixture is denser than 80:20 due to higher oxygen content, reducing the therapeutic benefit. 1
• Heliox cannot be used if patients require >30% oxygen, as the mixture requires at least 70% helium for therapeutic effect. 3

Oxygen Saturation Targets During Heliox Administration

• Target SpO2 94-98% for patients with asthma or upper airway obstruction. 1
• Target SpO2 88-92% for patients with severe COPD. 1, 3
• Continuous pulse oximetry monitoring is essential throughout heliox administration. 1

Important Technical Caveats

Equipment Interference

• Heliox affects calibration and functioning of respiratory equipment, including peak flow meters and spirometry (FEV1 measurements). 1, 3
• Standard Wright peak flow meters require recalibration for heliox use. 5
• Specialized nebulizer systems are required if using heliox as a driving gas for aerosolized medications. 1, 3

Monitoring Requirements

• Vigilant continuous monitoring is mandatory to avoid technical complications, though heliox itself has no reported adverse effects beyond temporary voice alteration. 1, 6
• Monitor for adequate oxygen delivery throughout therapy. 3, 6

When NOT to Use Heliox

Heliox is not recommended for:

• Routine management of mild-to-moderate asthma or bronchiolitis. 2
• Initial treatment of asthma exacerbations (meta-analyses do not support this use). 2, 3
• COPD exacerbations (no reduction in intubation rates, ventilation duration, or mortality). 3
• Any condition outside of randomized clinical trials, except mechanical upper airway obstruction. 1

The evidence base for heliox remains weak in most respiratory conditions, with no demonstrated mortality or morbidity benefit despite higher costs compared to oxygen-air mixtures. 1, 2, 3, 7