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

Airway Obstruction Clinical Trial

Official title:

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

Clinical Trial Details — Status: Active, not recruiting

Administrative data

• NCT number: NCT06457399
• Other study ID #: HELIOX ON AIRWAY STENOSIS
• Status: Active, not recruiting
• Start date: April 27, 2022
• Est. completion date: November 2024

Study information

• Verified date: June 2024
• Source: Hospital Universitario 12 de Octubre
• Contact: n/a
• Is FDA regulated: No
• Study type: Observational

Clinical Trial Summary

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.

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.

Recruitment information / eligibility

• Status: Active, not recruiting
• Enrollment: 18
• Est. completion date: November 2024
• Est. primary completion date: May 31, 2023
• Accepts healthy volunteers: No
• Gender: All
• Age group: 18 Years to 80 Years

Eligibility

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.

Related Conditions & MeSH terms

• Airway Obstruction
• Constriction, Pathologic

Intervention

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.
• Oxygen
Treatment for 30 minutes with oxygen at FiO2 of 31% with Venturi mask.

Locations

Country	Name	City	State
Spain	Marta Corral Blanco	Madrid

Sponsors (1)

Lead Sponsor	Collaborator
Hospital Universitario 12 de Octubre

Country where clinical trial is conducted

Spain, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	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	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.
Secondary	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.
Secondary	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.
Secondary	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.
Secondary	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.
Secondary	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.
Secondary	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.
Secondary	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.
Secondary	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.