Heliox on the Work of Breathing in Adult Patients With Lower Airway Stenosis

The Effect of Heliox on the Work of Breathing in Adult Patients With Lower Airway Stenosis

Heliox (a mixture of Helium and Oxygen) can reduce the work of breathing in patients with airway stenosis by modifying turbulent flow into laminar flow. The aim of this study was to analyze the effect of Heliox versus conventional oxygen therapy in patients with lower airway stenosis on muscular effort measured by electromyography and diaphragmatic ultrasound, thoracoabdominal synchrony assessed with plethysmographic bands, dyspnea, stridor, oxygen saturation, transcutaneous carbon dioxide value, blood pressure, heart rate and respiratory rate.

Study Overview

• Status: Active, not recruiting
• Conditions: Airway Obstruction
• Intervention / Treatment: Drug: Heliox; Drug: Oxygen

Detailed Description

Lower airway stenosis results in increased work of breathing with stridor and dyspnea, as a consequence of the increased resistances caused by the reduction in airway diameter. Airway resistance also depends on the length of the airway and the type of gas flow. Heliox (a mixture of Helium and Oxygen) is a gas less dense than air, which can change the flow from turbulent to laminar, reducing airway resistance by 20 to 40%, and therefore decreasing the work of breathing. Heliox is an inert gas that does not react with biological membranes, so there are few complications associated with its use, the most relevant being hypoxemia when fixed mixtures are not used and the the fraction of inspired oxygen (FiO2) supplied is less than 21%. The aim of the study was to evaluate if during the perioperative period of lower airway stenosis the administration of Heliox compared to oxygen could reduce the work of breathing and improve dyspnea. For this purpose, patients were treated for 30 minutes with Heliox (fixed mixture of 70% helium and 30% oxygen) using a non rebreather mask or reservoir bag versus 30 minutes with oxygen 31% using a Venturi mask.

• Study Type: Observational
• Enrollment (Actual): 18

Contacts and Locations

Study Locations

• Spain
  • Madrid, Spain, 28041
    • Marta Corral Blanco

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Patients will be recluted from the pneumology outpatient clinic of the Hospital 12 de Octubre

Description

Inclusion Criteria:

• Patients with lower airway stenosis evaluated at the Respiratory Endoscopy Unit of the Hospital Universitario 12 de Octubre on the waiting list for endoscopic intervention on stenosis.
• Stenosis grade ≥ 3 and Borg scale score > 2.

Exclusion Criteria:

• Presence of relevant comorbidities (uncontrolled ischemic heart disease, ventricular dysfunction, pneumopathies with severe respiratory insufficiency, severe pulmonary hypertension).
• Inability to perform the test due to severe dyspnea or need for emergency intervention.
• Patient on continuous mechanical ventilation, invasive or non-invasive.

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Airway Stenosis; Patients with lower airway stenosis on waiting list for endoscopic intervention on stenosis by respiratory endoscopy unit.	Drug: Heliox; Treatment for 30 minutes with Heliox from a commercial tank (Oxhelⓒ, Air Liquideⓒ) with a fixed mixture of 70% helium and 30% oxygen with non-rebreather mask or reservoir bag at a flow of 12-15 lpm.; Other Names: Helium - Oxygen; Drug: Oxygen; Treatment for 30 minutes with oxygen at FiO2 of 31% with Venturi mask.; Other Names: Oxygen 31%

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes in Neural Ventilatory Drive (%):	Percentage over the Root Mean Square peak for parasternal electromyography (EMG): averaged of the square root of the peak value and the area under the curve of parasternal EMG (%RootMeanSquare) adjusted for respiratory frequency, as a surrogate of diaphragmatic EMG, and sternocleidomastoid EMG, which will give us information on accessory muscle activation.	30 minutes with Heliox and 30 minutes with Oxygen 31%

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Diaphragmatic excursion assessed with ultrasound	Assessment of muscular effort by measuring the diaphragmatic excursion (mm) at tidal volume and at vital capacity.	At minute 15 during the Heliox test and at minute 15 during the Oxygen 31% test.
Thickening fraction of the diaphragm assessed by ultrasound	Assessment of muscular effort by measuring the thickening fraction of the diaphragm in the apposition zone (%).	At minute 15 during the Heliox test and at minute 15 during the Oxygen 31% test.
Changes in thoracoabdominal synchrony	Assessment of thoracoabdominal synchrony using thoracic and abdominal belts by calculating the phase angle with the Lissajoux loop method (plotting abdominal motion on the x-axis against thoracic motion on the y-axis).	Phase angle was calculated from 10 consecutive breaths at minutes 1, 5, 15 and 30 during the Heliox test and the Oxygen 31% test.
Borg Scale Dyspnea evolution (points)	Degree of dyspnea will be determined by this validated scale with a result between 1 and 10 points.0: Not at all 0.5: Very, very light (hardly noticeable) 1: Very light, 2: Light, 3: Moderate , 4: Somewhat intense, 5: Intense, 6: Between 5 and 7, 7: Very intense, 8: Between 7 and 9, 9: Very, very intense (almost maximum ), 10: Maximum	Basal value and at minutes 1, 5, 15 and 30 during the Heliox test and the Oxygen 31% test.
Oxygen saturation	Measured by pulse-oximetry	Basal value and at minutes 1, 5, 15 and 30 during the Heliox test and the Oxygen 31% test.
Transcutaneous partial pressure of carbon dioxide	Transcutaneous monitor uses a noninvasive technique to measure the skin-surface partial pressure of carbon dioxide (PtcCO2)	Basal value and at minutes 1, 5, 15 and 30 during the Heliox test and the Oxygen 31% test.
Blood pressure	Non-invasive measurement with a sphygmomanometer	Basal value and at minutes 1, 5, 15 and 30 during the Heliox test and the Oxygen 31% test.
Heart rate	number of beats per minute	Basal value and at minutes 1, 5, 15 and 30 during the Heliox test and the Oxygen 31% test.
Respiratory rate	Number of breaths per minute	Basal value and at minutes 1, 5, 15 and 30 during the Heliox test and the Oxygen 31% test.

Collaborators and Investigators

• Sponsor: Hospital Universitario 12 de Octubre
• Investigators: Principal Investigator: Marta Corral Blanco, MD, Hospital 12 de Octubre

Study record dates

Study Major Dates

• Study Start (Actual): April 27, 2022
• Primary Completion (Actual): May 31, 2023
• Study Completion (Estimated): November 1, 2024

Study Registration Dates

• First Submitted: May 30, 2024
• First Submitted That Met QC Criteria: June 7, 2024
• First Posted (Actual): June 13, 2024

Study Record Updates

• Last Update Posted (Actual): June 13, 2024
• Last Update Submitted That Met QC Criteria: June 7, 2024
• Last Verified: June 1, 2024

More Information

Terms related to this study

• Keywords: Work of breathing; Heliox; Airway resistance; Airway Stenosis
• Additional Relevant MeSH Terms: Respiratory Tract Diseases; Respiration Disorders; Pathological Conditions, Anatomical; Respiratory Insufficiency; Constriction, Pathologic; Airway Obstruction
• Other Study ID Numbers: HELIOX ON AIRWAY STENOSIS

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No