Emerging Therapies for Patients with Airway/Respiratory DiseaseHeliox in Airway Management
Section snippets
History
The element helium was discovered in 1868 when the French astronomer Janssen observed a bright yellow line in the sun's atmosphere during a total solar eclipse in India. The gas was given its name later that year when the English astronomer Lockyer also observed it in the solar spectrum and, concluding that it was an element in the sun not found on Earth, named it after the Greek word for sun, helios. Once its physical properties were delineated, many useful applications for helium became
Prior research
In the 1930s, A.L. Barach tested various mixtures of helium and oxygen, finding benefit across a range of concentrations in asthmatic patients and infants with airway obstruction. He concluded that the low density of helium decreased the work of breathing and significantly improved ventilation. There was a paucity of systematic research on heliox until the 1970s; at that time, investigations into its potential benefit in UAO, postextubation stridor, croup, bronchiolitis, asthma, and chronic
Current research
Research in the past decade has focused on pediatric populations with UAOs and lower airway obstructions (LAOs), particularly asthma. In adults, many case reports and case series have been published on the benefit of heliox in UAO; the only randomized clinical trials have studied the use of heliox in asthma or COPD exacerbations. Other issues of concern include determination of the ideal gas mixture (at least 60% helium seems to be most effective; 80% helium means the gas mixture is hypoxic
Physiology of heliox
In several studies, heliox has been found to decrease the work of breathing and improve gas delivery to the lungs. A review of the physical properties of helium and some of the laws of physics that apply to respiratory physiology can help to explain these results.
Helium is a colorless, odorless, tasteless, biologically inert, and therefore nontoxic gas. It is the second most abundant element in the universe (after hydrogen) but is relatively rare on Earth, requiring production by radioactive
Review of current clinical literature
In general, most heliox studies are limited by small sample sizes. Additionally, because UAO or severe LAO is generally an emergent condition, there has been a paucity of controlled studies done in these areas.
To assess objectively the value of each of the publications considered here, a classification system is used based on the study type (including case series) and the rigors of the study design (if any). This approach (Box 1) is modeled after the classification system used in the Guidelines
Research on the use of heliox in children
The small anatomy and reactive physiology of infants and young children put them at greater risk for airway obstruction than older children and adults. Their upper and lower airways are small, predisposed to blockage by secretions, and vulnerable to edema and resultant airway narrowing. As noted previously, resistance to laminar airflow increases in inverse proportion to the fourth power of the airway radius (Hagen-Poiseuille's law); therefore, a small decrease in the radius of the airway
Upper airway obstruction
There are many causes of UAO—acute, as in foreign body aspiration or acute epiglottitis, and more insidious in nature, such as a slow-growing mass. Regardless of the cause, UAO can precipitate acute ventilatory failure.2 Obstruction increases airway resistance, causing increased work of breathing; this eventually leads to respiratory muscle fatigue and the life-threatening problems of hypercapnia and hypoxemia. The obvious goal of removing the obstruction may not always be accomplishable in an
Lower airway obstruction
A study done in 2002 by Piva and colleagues10 tested 20 children with chronic LAO, randomizing them to heliox or oxygen for ventilatory scintigraphy testing (ie, ventilation/perfusion [V/Q] scan). Results showed better gas distribution (lung deposition) with heliox in those with severe LAO; however, there was no difference between oxygen and heliox in milder obstruction, as designated by prior pulmonary function tests. These findings are supported by the previously reviewed respiratory
Upper Airway Obstruction
As with the pediatric population, much of the literature on the use of heliox in adults with UAO is limited to case descriptions.
In the previously mentioned 1999 case report by Smith and Biros,9 two of the five patients were adults who had UAO: one with supraglottitis and one with laryngeal polyps and edema. This class III report examined two adults in severe respiratory distress who were treated in the ED and responded rapidly to heliox, avoiding mechanical ventilation. These investigators
Summary
Overall, the data continue to be inconclusive regarding the overall benefit of heliox in UAO and LAO; however, the following areas seem to be supported in the literature.
Heliox, because of its lower density than air or oxygen regardless of the concentration of helium in the mixture, increases gas particle deposition and improves air flow through constricted passageways by transforming turbulent flow into laminar flow; some studies have shown a concomitant decrease in the work of breathing.
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Safety and efficacy of heliox as a treatment for upper airway obstruction due to radiation-induced laryngeal dysfunction
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Helium-oxygen mixtures in intubated patients with status asthmaticus and respiratory acidosis
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Helium oxygen breathing in severe chronic obstructive pulmonary disease
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The Effect of heliox on nebulizer function using a beta-agonist bronchodilator
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Room air entrainment during β-agonist delivery with heliox
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Guidelines for the acute medical management of severe traumatic brain injury in infants, children, and adolescents
Pediatr Crit Care Med
Helium-oxygen mixture in the treatment of postextubation stridor in pediatric trauma patients
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Helium-oxygen in the postextubation period decreases inspiratory effort
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Use of a helium-oxygen mixture in the treatment of postextubation stridor in pediatric patients with burns
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The use of heliox and the laryngeal mask airway in a child with an anterior mediastinal mass
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The effect of heliox on croup: a pilot study
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A randomized comparison of helium-oxygen mixture (Heliox) and racemic epinephrine for the treatment of moderate to severe croup
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Relief of imminent respiratory failure from upper airway obstruction by use of helium-oxygen: a case series and brief review
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Heliox vs. oxygen for nebulized aerosol therapy in children with lower airway obstruction
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Management of malignancy-induced, life-threatening hypoxemic respiratory failure using a self-expanding Y stent
2023, Respiratory Medicine Case ReportsCitation Excerpt :Another salvage therapy that was attempted was heliox at an 80%/20% mixture. Helium with its smaller atomic size offers greater potential for laminar flow and can be useful as a temporizing measure [1,2]. In this case, heliox was not a successful strategy because of the difficulties encountered in delivering the heliox mixture effectively through non-invasive ventilation.
Update on Tracheostomy and Upper Airway Considerations in the Head and Neck Cancer Patient
2022, Surgical Clinics of North AmericaCitation Excerpt :In the patient with respiratory distress related to upper airway compromise, medications such as heliox, steroids, and racemic epinephrine may bridge patients before intubation or establishment of a surgical airway. Heliox is a biologically inert gas, which decreases work of breathing and improves gas delivery to the lungs by reducing airflow resistance and transforming turbulent airflow into laminar airflow.10 Although more widely studied in pediatric populations and most benefits being reported in small, observational studies, it is a safe temporizing measure.10
Noninvasive Ventilation as a Temporizing Measure in Critical Fixed Central Airway Obstruction: A Case Report
2018, Journal of Emergency MedicineCitation Excerpt :Helium-oxygen mixture (heliox) is an infrequently cited example of such a therapeutic bridge (2,17). Although existing literature of its use is limited to application mainly in pediatric respiratory diseases and obstruction of small airways like asthma and chronic obstructive pulmonary disease, the low density of helium enables greater and more laminar flow of gases down a smaller pressure gradient across a partially obstructed airway (18). This physical property may be extrapolated to benefit patients with CAO by decreasing turbulent airflow at the point of obstruction.
Helium–oxygen mixture for treatment in upper airway obstruction; a mini-review
2016, Journal of Acute MedicineCitation Excerpt :However, there is still limited and inconsistent data to support that the theory works in practice. The potential benefits around helium for the handling of upper airway obstruction is addressed is several review papers but the actual critical information in humans is limited to the papers presented in our results.1–4,25–32 We found only sparse information and there are obvious deficits in the evidence to support its general use.
Descriptive study on the use of heliox in Pediatric Intensive Care patients in the Ortopedia Infantil Roosevelt Institute, Colombia
2015, Acta Colombiana de Cuidado IntensivoModified slide tracheoplasty in a newborn with bronchial and carinal stenosis
2013, International Journal of Pediatric Otorhinolaryngology