Heliox Therapy: Uses, Indications, and Effects (2024)

Heliox therapy, a blend of helium and oxygen, has been a cornerstone in respiratory care for managing airway obstruction and reducing the work of breathing.

With its unique physical properties, heliox minimizes airway resistance and enhances airflow, offering a valuable solution in conditions like asthma, chronic obstructive pulmonary disease (COPD), and croup.

Originally introduced in the 1930s, heliox has since evolved to support both acute and chronic respiratory challenges. This article explores the science behind heliox, its clinical applications, benefits, and ongoing research shaping its future in respiratory medicine.

What is Heliox Therapy?

Heliox therapy is a medical treatment that utilizes a mixture of helium and oxygen, known as heliox, to assist in managing various respiratory conditions. This unique gas mixture is designed to reduce airway resistance and improve airflow, making it easier for patients to breathe.

The key benefit of heliox lies in the properties of helium, which has a much lower density compared to atmospheric air. When combined with oxygen, heliox facilitates smoother airflow through constricted or obstructed airways, decreasing the work of breathing and enhancing gas exchange. Heliox therapy is often used as a supportive measure in conditions such as asthma, chronic obstructive pulmonary disease (COPD), croup, and other respiratory ailments.

The composition of heliox can vary based on clinical needs, with common mixtures including:

• 80/20 Heliox: 80% helium and 20% oxygen, suitable for patients who need less supplemental oxygen.
• 70/30 Heliox: 70% helium and 30% oxygen, used for patients requiring slightly more oxygen.

Heliox therapy is not a cure for underlying respiratory diseases but rather a supportive intervention. By improving airflow dynamics and reducing the effort required for breathing, it helps stabilize patients while other treatments address the root causes of their conditions.

Indications for Heliox Therapy

Heliox therapy is primarily indicated for conditions that involve airway obstruction, increased work of breathing, or impaired airflow dynamics. By reducing airway resistance and promoting smoother airflow, heliox therapy provides relief in a variety of acute and chronic respiratory conditions.

Common indications include:

• Upper airway obstruction
• Chronic obstructive pulmonary disease (COPD)
• Asthma exacerbation
• Severe respiratory failure
• Acute respiratory distress syndrome (ARDS)
• Laryngeal obstruction
• Subglottic stenosis
• Acute vocal cord dysfunction
• Bilateral vocal cord paralysis
• Croup
• Pneumonia
• Bronchiolitis
• Endotracheal and endobronchial disease
• Mediastinal mass
• Congenital diaphragmatic hernia (CDH)
• Nebulized drug delivery
• Pulmonary rehabilitation
• Improved exercise performance
• Pulmonary function testing (PFT)

Note: Heliox therapy is especially useful in managing acute airway obstruction and reducing respiratory distress. While it is not a first-line treatment for all conditions, its ability to decrease turbulence and facilitate laminar flow makes it a valuable tool in specific clinical scenarios, especially when standard treatments are insufficient.

Heliox Composition

Heliox is a carefully formulated gas mixture consisting of helium and oxygen. The specific composition varies based on the clinical requirements of the patient, with the two most common blends being:

• 80/20 Heliox: This mixture comprises 80% helium and 20% oxygen. It is primarily used for patients who have adequate oxygenation but benefit from reduced airway resistance and improved airflow. The high helium content significantly lowers the density of the gas mixture, facilitating smoother, less turbulent airflow through narrowed or obstructed airways. This blend is ideal for conditions where minimizing the work of breathing is critical, such as in cases of airway obstruction or severe asthma exacerbations.
• 70/30 Heliox: Containing 70% helium and 30% oxygen, this mixture is suitable for patients who require a higher level of oxygen supplementation while still benefiting from the low-density properties of helium. It provides a balance between oxygenation and the therapeutic advantages of reduced airway resistance.

Important Considerations

While heliox offers significant advantages in terms of airflow dynamics and reduced respiratory muscle workload, its helium content inherently lowers the percentage of oxygen in the mixture. This means:

• Patients with high oxygen demands may not be suitable candidates for heliox therapy, as the reduced oxygen content might not meet their needs.
• Cautious monitoring of oxygen saturation and overall respiratory status is essential when using heliox to ensure patient safety and therapeutic efficacy.

Note: Heliox compositions are selected based on the patient’s specific respiratory condition and oxygen requirements, with the goal of achieving the best balance between improved airflow and adequate oxygenation. Proper evaluation by healthcare professionals ensures the safe and effective use of this therapy.

Physiological Effects of Heliox

Heliox has unique physical properties that create significant physiological benefits, especially in conditions involving airway obstruction or increased respiratory effort. Its low density and high thermal conductivity influence how air flows through the respiratory system, offering relief and improving breathing efficiency.

Here are the key physiological effects of heliox:

• Reduced Airway Resistance: Heliox has a much lower density compared to atmospheric air, reducing the resistance encountered during airflow. This is particularly beneficial in obstructive airway diseases like asthma, chronic obstructive pulmonary disease (COPD), or upper airway obstructions. By lowering airway resistance, heliox decreases the energy required to move air through the respiratory tract, making it easier for patients to breathe.
• Promotion of Laminar Flow: In normal air, turbulent flow occurs in narrowed airways, increasing resistance. The low density of heliox facilitates smoother, laminar flow even in constricted airways. Laminar flow is less resistant than turbulent flow, which significantly reduces the work of breathing, especially in smaller airways.
• Improved Gas Exchange: Heliox enhances the distribution of ventilation in the lungs by reducing airflow turbulence. This leads to better oxygen delivery to alveoli and more efficient carbon dioxide removal. Improved ventilation-perfusion matching helps optimize gas exchange, particularly in patients with severe airway narrowing.
• Reduced Work of Breathing: By lowering airway resistance and promoting laminar airflow, heliox reduces the effort required to ventilate the lungs. This is especially important for patients experiencing respiratory distress or fatigue, as it conserves energy and prevents respiratory muscle exhaustion.
• Enhanced Aerosolized Drug Delivery: Heliox’s low density allows aerosolized medications, such as bronchodilators, to be delivered more effectively to distal airways. The reduced turbulence helps medications penetrate deeper into the lungs, making treatments for conditions like asthma or COPD more efficient.
• Stabilization of Breathing Mechanics: In mechanically ventilated patients, heliox can lower peak airway pressures, improve carbon dioxide diffusion, and reduce dynamic hyperinflation. It provides smoother, more controlled breathing cycles, reducing the strain on the lungs.

Heliox’s ability to reduce airway resistance, improve airflow dynamics, and enhance drug delivery makes it a powerful supportive therapy for various respiratory conditions.

However, it is not a cure for underlying diseases. Its role is to stabilize patients, relieve symptoms, and improve the effectiveness of other interventions while definitive treatments address the root cause.

Heliox Contraindications

Heliox therapy is generally considered safe and well-tolerated, with no intrinsic toxic properties. However, there are specific clinical situations and patient factors where its use may be inappropriate or ineffective.

These contraindications stem primarily from the limitations of its oxygen content and its unique physical properties:

• High Oxygen Requirements: Heliox mixtures, particularly the standard 80/20 and 70/30 blends, contain reduced levels of oxygen compared to atmospheric air. Patients with severe hypoxemia or conditions requiring high concentrations of oxygen (FiO₂ > 0.4) are not suitable candidates for heliox therapy, as it may not meet their oxygenation needs.
• Severe Respiratory or Cardiac Instability: In cases of profound respiratory failure or hemodynamic instability, where immediate and robust oxygen supplementation or other advanced interventions are necessary, heliox may not provide adequate support.
• High-Pressure Ventilation Needs: The low density of heliox makes it unsuitable for situations requiring high-pressure mechanical ventilation. It may not deliver sufficient driving pressure or volume for effective ventilation in these cases. Additionally, heliox should not be used with single-limb circuit ventilators (e.g., V60 or Trilogy devices) that rely on passive exhalation, as the flow inconsistencies can compromise therapy.
• Insufficient Equipment or Training: Heliox delivery requires specialized equipment, such as heliox-compatible flow meters, ventilators, and analyzers, to ensure accurate administration and monitoring. Facilities lacking the necessary tools or staff trained in heliox application may find its use impractical or unsafe.
• Cost and Resource Limitations: The expense and limited availability of helium make heliox therapy less feasible in some clinical settings. Its cost-effectiveness should be considered, especially in resource-limited environments where alternative therapies may suffice.
• Non-Obstructive Respiratory Conditions: Heliox is primarily beneficial in conditions involving airway obstruction or increased airway resistance. It offers limited or no benefit in non-obstructive conditions where the underlying issue does not affect airflow dynamics.

Note: Heliox therapy offers significant benefits in managing respiratory conditions involving airway obstruction. However, its use should be guided by a thorough clinical evaluation, with careful attention to oxygenation needs, equipment availability, and the patient’s overall stability. Inappropriate use may result in suboptimal outcomes or delayed initiation of more effective therapies.

Heliox Flow Rate Calculation

Accurately calculating the flow rate of heliox is essential for ensuring effective therapy and patient safety. The unique properties of heliox, such as its lower density compared to air, require adjustments to account for its behavior when delivered through standard oxygen flow meters.

Heliox is typically available in two common compositions:

• 80% helium and 20% oxygen (80/20)
• 70% helium and 30% oxygen (70/30)

Each mixture has a specific correction factor used to calculate the actual flow rate delivered to the patient:

• 80/20 Heliox Factor: 1.8
• 70/30 Heliox Factor: 1.6

Formula for Calculating Actual Flow Rate

To determine the actual flow rate of heliox delivered to the patient, use the following formula:

Actual Flow Rate (L/min) = Given Flow Rate (L/min) × Heliox Factor

Example Calculation

Suppose a patient is receiving heliox with an 80/20 mixture at a flow meter setting of 10 L/min. Using the correction factor for 80/20 heliox (1.8), the actual flow rate can be calculated as follows:

Actual Flow Rate = 10 L/min × 1.8 = 18 L/min

In this case, although the flow meter indicates 10 L/min, the patient is receiving an actual flow of 18 L/min due to the properties of the heliox mixture.

Heliox’s low density causes it to flow differently through standard oxygen equipment. Without these adjustments:

• Patients may receive incorrect flow rates, potentially compromising therapy effectiveness.
• The clinical goals of heliox therapy, such as reducing airway resistance and improving ventilation, might not be fully achieved.

Note: By applying the appropriate correction factor, healthcare professionals ensure precise delivery, optimizing the therapeutic benefits of heliox.

Key Considerations

• Always confirm the heliox mixture being used to apply the correct factor.
• Ensure the flow meter is calibrated for heliox or account for the correction factor if using a standard oxygen flow meter.
• Monitor patient response and adjust the flow rate as needed to maintain effective therapy.

Note: Accurate calculations are a critical step in delivering safe and effective heliox therapy.

Heliox Flow Conversion Table

This chart is a Heliox Flow Conversion Table, used to determine the actual flow rate of heliox delivered to a patient when using a standard oxygen flow meter.

Since oxygen flow meters are calibrated for oxygen and not for heliox, adjustments are necessary due to the unique physical properties of helium.

The chart consists of three columns: the given flow rate, the actual flow rate for an 80/20 heliox mixture, and the actual flow rate for a 70/30 heliox mixture.

The first column lists the flow rates as set on the oxygen flow meter. The second column shows the actual flow rate delivered when using an 80% helium and 20% oxygen mixture, calculated by multiplying the given flow rate by a conversion factor of 1.8. The third column provides the actual flow rate for a 70% helium and 30% oxygen mixture, calculated using a conversion factor of 1.6.

For example, if the flow meter is set to 10 L/min, the actual flow delivered with an 80/20 mixture would be 18 L/min, while for a 70/30 mixture, it would be 16.9 L/min.

Note: This conversion ensures the patient receives the intended flow rate, as heliox flows faster than oxygen due to its lower density. Accurate flow rate calculations are crucial for effective therapy, helping reduce airway resistance and optimize the benefits of heliox.

Heliox vs. Nitric Oxide

Heliox and nitric oxide are both gases utilized in medical treatments, particularly for respiratory and cardiovascular conditions. However, they have distinct properties, mechanisms of action, and therapeutic applications:

Heliox

Heliox is a gas mixture composed of helium and oxygen, commonly available in 80/20 or 70/30 blends. Its unique properties include:

• Low Density: Heliox is significantly less dense than air, which reduces airway resistance and promotes laminar airflow in the lungs. This effect minimizes turbulence, making breathing easier for patients with airway obstruction.
• Improved Gas Exchange: By reducing resistance and work of breathing, heliox optimizes ventilation and oxygenation.
• Enhanced Drug Delivery: Heliox facilitates deeper delivery of aerosolized medications to distal airways, improving treatment efficacy in obstructive lung diseases.

The primary uses of Heliox include:

• Asthma: Helps reduce airway resistance during severe exacerbations.
• Chronic Obstructive Pulmonary Disease (COPD): Decreases the work of breathing and enhances drug delivery during exacerbations.
• Croup: Relieves airway obstruction in pediatric patients.
• Airway Obstruction: Useful in conditions like laryngeal edema, vocal cord dysfunction, or subglottic stenosis.

Nitric Oxide

Nitric oxide (NO) is a potent vasodilator with unique effects on the pulmonary vasculature. When inhaled, it selectively dilates pulmonary blood vessels in well-ventilated areas of the lung, improving the matching of ventilation to perfusion (V/Q matching).

The mechanism of action of nitric oxide includes:

• Selective Pulmonary Vasodilation: Reduces pulmonary artery pressure without causing systemic hypotension.
• Enhanced Oxygenation: Improves oxygen delivery by increasing blood flow to ventilated lung regions.

The primary uses of nitric oxide include:

• Persistent Pulmonary Hypertension of the Newborn (PPHN): Reduces pulmonary artery pressure and improves oxygenation in neonates.
• Hypoxic Respiratory Failure: Used in conditions like acute respiratory distress syndrome (ARDS) to improve oxygenation in adults.
• Pulmonary Hypertension: Manages elevated pulmonary pressures associated with right heart strain.

While heliox and nitric oxide both play significant roles in respiratory care, they address different physiological challenges. Heliox focuses on enhancing airflow and reducing work of breathing, while nitric oxide targets pulmonary vascular pressures to improve oxygenation.

Note: Both therapies require specialized equipment and careful monitoring, with treatment tailored to the patient’s specific condition and clinical needs.

Ongoing Research On Heliox

Heliox therapy, which involves administering a mixture of helium and oxygen to patients, has been a subject of medical interest since the 1930s. Its primary application has been in managing respiratory conditions characterized by airway obstruction.

Recent research continues to explore its efficacy, optimal delivery methods, and potential new applications:

• Clinical Applications and Efficacy: Heliox has shown benefits in conditions like asthma, COPD, croup, and bronchiolitis by reducing airway resistance and improving airflow. However, evidence is mixed. For example, a Cochrane review found heliox offered no significant advantage over standard treatments for croup. In mechanical ventilation, heliox can reduce peak airway pressures and improve gas exchange, but its impact on clinical outcomes like ICU stay duration remains uncertain.
• Aerosol Drug Delivery: Studies have investigated using heliox to enhance aerosolized drug delivery, such as bronchodilators, by improving medication penetration into the lower airways. While promising, more research is needed to validate its effectiveness.
• Emerging Applications: New areas of research include heliox for acute respiratory distress syndrome (ARDS) and improving exercise performance in COPD patients by reducing dynamic hyperinflation. These potential applications show promise but require further clinical trials.
• Challenges and Future Directions: Heliox therapy faces hurdles, including high costs, limited helium resources, and the need for specialized equipment. Future research aims to identify patient populations most likely to benefit, optimize delivery methods, and strengthen the evidence base with large-scale studies.

Note: While heliox therapy offers significant potential, ongoing research is essential to clarify its role in respiratory care.

FAQs About Heliox

What is Heliox Therapy, and How Does It Work?

Heliox therapy is a medical treatment that uses a mixture of helium and oxygen to assist patients with breathing difficulties. The therapy works by taking advantage of helium’s low density, which reduces airway resistance and promotes smoother airflow.

This property makes breathing easier for patients with obstructive airway conditions, such as asthma or chronic obstructive pulmonary disease (COPD). By improving airflow dynamics, heliox decreases the work of breathing and enhances the delivery of oxygen to the lungs, providing relief from respiratory distress.

Why is Helium Used in Heliox Therapy?

Helium is used in heliox therapy because it has a much lower density than air. This low density reduces turbulence in the airways, allowing for smoother and more efficient airflow.

Helium’s unique properties facilitate laminar (smooth) flow, even in narrowed or obstructed airways, which decreases airway resistance and the effort required to breathe. Its inert and non-toxic nature also makes it safe for medical use, ensuring it does not interact with tissues or medications.

When is Heliox Therapy Indicated?

Heliox therapy is indicated for conditions where reducing airway resistance and respiratory effort is beneficial. Common indications include:

• Upper Airway Obstructions: Such as croup, laryngeal edema, or subglottic stenosis.
• Obstructive Lung Diseases: Including asthma exacerbations and COPD.
• Post-Extubation Stridor: To ease breathing after the removal of an endotracheal tube.
• Severe Respiratory Distress: To stabilize patients while addressing the underlying cause.

Note: Heliox is often used as a supportive therapy when conventional treatments are insufficient to manage respiratory challenges effectively.

What Ii Heliox 80/20 vs. 70/30?

Heliox 80/20 and 70/30 refer to the two most common mixtures of helium and oxygen used in heliox therapy.

• Heliox 80/20: This mixture contains 80% helium and 20% oxygen. It is typically used for patients with adequate oxygen levels who primarily need the benefits of reduced airway resistance and improved airflow dynamics.
• Heliox 70/30: This mixture consists of 70% helium and 30% oxygen. It is used for patients who require more oxygen while still benefiting from helium’s properties.

Note: The choice between these mixtures depends on the patient’s oxygenation needs and respiratory condition, as determined by the healthcare provider.

What is the Mechanism of Action of Heliox Therapy?

The mechanism of action of heliox therapy is rooted in helium’s low density. This property reduces airway resistance by promoting laminar airflow in the lungs, even through narrowed or obstructed airways.

In turbulent flow conditions, resistance is directly proportional to gas density, and the reduced density of heliox significantly lowers this resistance. As a result:

• The work of breathing is decreased.
• Ventilation is more evenly distributed, improving oxygen delivery and carbon dioxide removal.
• Heliox can enhance the effectiveness of aerosolized medications by allowing them to reach deeper parts of the lungs.

Note: These effects make heliox a valuable tool for managing respiratory distress and airway obstruction.

How Does Heliox Help Stridor?

Stridor is a high-pitched sound caused by airflow obstruction in the upper airway. Heliox helps alleviate stridor by reducing airway resistance and improving airflow through the narrowed or obstructed areas.

The low density of helium minimizes turbulence, allowing smoother and more efficient airflow. This can provide immediate relief from breathing difficulties associated with stridor while underlying causes, such as swelling or obstruction, are addressed.

Why Would Heliox Be Considered for Treating an Asthma Exacerbation?

Heliox may be considered for treating severe asthma exacerbations because it reduces airway resistance and the effort required to breathe. During an exacerbation, inflamed and narrowed airways increase turbulence and resistance, making it harder for patients to exhale.

Heliox’s low density promotes laminar airflow, easing respiratory effort. Additionally, heliox enhances the delivery of aerosolized medications, such as bronchodilators, ensuring they reach deeper parts of the lungs, improving their effectiveness. It is particularly useful when standard therapies are insufficient to manage the condition.

What Mask is Used for Heliox?

The most common masks used for heliox therapy are non-rebreather masks (NRB) and Venturi masks.

Nonrebreather Mask: This mask delivers a high concentration of the heliox mixture and prevents room air from diluting the gas, ensuring the patient receives the intended therapeutic benefits.
Venturi Mask: This can also be used but may require adjustments to ensure proper flow rates of heliox.

Note: Proper mask fit is critical to minimize gas leakage and ensure optimal delivery of the heliox mixture.

How Do You Administer Heliox Therapy?

Heliox therapy is administered via inhalation using specialized equipment and techniques. Common delivery methods include:

• Nonrebreather Masks: For patients needing higher concentrations of heliox without mechanical ventilation.
  Nasal Cannulas: For mild cases requiring lower flow rates.
• Mechanical Ventilators: For patients who are intubated or require noninvasive positive pressure ventilation. Ventilators must be compatible with heliox to ensure accurate gas delivery.

Note: Flow meters calibrated for heliox are preferred. If using an oxygen flow meter, a correction factor (1.8 for 80/20 and 1.6 for 70/30) is applied to calculate the actual flow rate.

What Devices Are Used for Heliox Therapy?

Several devices are used to deliver heliox therapy, including:

• Heliox Flow Meters: Calibrated specifically for heliox to provide accurate flow rates.
• Mechanical Ventilators: Some models are compatible with heliox and allow for precise delivery during invasive or noninvasive ventilation.
• Nebulizers: Used to deliver aerosolized medications in conjunction with heliox for deeper drug penetration.
• High-Flow Nasal Cannulas (HFNC): For delivering heliox at higher flow rates while maintaining patient comfort.

Note: Specialized equipment ensures that the unique properties of heliox are utilized effectively and safely.

Does Heliox Change Your Voice?

Yes, heliox can temporarily change your voice. Because helium is less dense than air, it alters the speed of sound waves traveling through the vocal cords.

This results in a higher-pitched, “squeaky” voice while inhaling the heliox mixture. The effect is harmless and reverses as soon as the heliox therapy is discontinued.

Is Heliox Still Used?

Yes, heliox is still used, though its application is limited to specific respiratory conditions and clinical scenarios. It remains a valuable tool in managing acute airway obstruction, croup, severe asthma exacerbations, and COPD.

However, the high cost of helium and the availability of alternative therapies have somewhat restricted its routine use. Heliox continues to be an important option in cases where reducing airway resistance is critical.

Is There a Role for Heliox Therapy in COVID-19?

Research suggests that heliox may have a role in managing severe respiratory distress caused by COVID-19, particularly in cases of acute respiratory distress syndrome (ARDS). Studies have documented its ability to improve gas exchange, reduce respiratory effort, and potentially prevent intubation in select cases.

However, its use is generally considered adjunctive and depends on the availability of resources and the patient’s specific condition. Further research is needed to establish definitive guidelines for its role in COVID-19 care.

Final Thoughts

Heliox therapy represents a unique approach to respiratory care, leveraging the low density of helium to improve breathing mechanics and enhance treatment efficacy.

While its benefits in managing airway obstruction and reducing respiratory effort are well-documented, its broader adoption is limited by factors like cost and availability. Continued research is critical to unlock new applications, refine delivery methods, and expand its accessibility in clinical settings.

As heliox continues to evolve, it remains an essential tool in the respiratory therapist’s arsenal, bridging gaps in care for patients with complex breathing difficulties.