Clinical trial NCT00788788: Heliox in Experimental Upper Airway Obstruction
Official title: PoC Study of Heliox With Helium-Fractions Between 25 and 75% in Experimental Upper Airway Obstruction
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: PHASE1
PHASE2
Conditions: Airway Obstruction
Dyspnea
Keywords: Airway obstruction
Heliox
Different Helium content
Lead sponsor: University of Witten/Herdecke
Sponsor class: OTHER
First posted: 2008-11-11
Enrollment: 44
Sex: ALL
Minimum age (years): 18
Maximum age (years): 60
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Primary purpose: TREATMENT

Brief summary: Currently it is common medical wisdom that HELIOX (mixture of Helium in Oxygen) with a fraction of Helium below 60% is not effective in reducing airway obstruction. The investigators test the hypothesis that HELIOX with a fraction of Helium below 60% is still effective in relieving airway obstruction in a double-blind, randomized and controlled clinical PoC study with experimental upper airway obstruction.

Detailed description: HELIOX is a mixture of Helium and Oxygen. It is a therapeutic modality that can improve upper and lower airway obstruction. The lower density of Helium can help to relieve airway obstruction and is known to lower the work of breathing. The fraction of Helium (FHe) in HELIOX should be maximized (e.g. up to a fraction of 79% with 21% of oxygen added) in order to achieve optimal anti-obstructive outcome and according to the literature a FHe below 60% renders HELIOX ineffective.

Objective: We conducted an investigator-initiated trial using different mixtures of Helium and Oxygen in 44 healthy volunteers in a randomized and double-blinded fashion.

Methods: After an adjustment phase the subjects were breathing through two different external resistors (intratracheal tube with inner diameter of either 4.0mm or 5.0mm) while gas of different composition (medical air with 79% Nitrogen and 21% Oxygen as control gas and HELIOX with a fraction of either 25%, 50% or 75% Helium in Oxygen, respectively) was provided in a blinded and random fashion. A crossover design was used so that every subject was exposed to every HELIOX gas mixture. Subjects were asked to score their degree of dyspnea after breathing different gas mixtures for 2 minutes intervals. In addition the variability of different hemodynamic parameters was assessed (continuous non-invasive blood pressure (systolic, diastolic and mean blood pressure), impedance cardiography (stroke volume and cardiac output), ECG (heart rate variability)) were assessed non-invasively and used to detected a change in the degree of airway obstruction in respect to the added load and the gas mixture.

Eligibility criteria: Inclusion Criteria:

* Volunteers of both sexes were recruited via posting in student forum of University of Witten/Herdecke
* Willingness to spend about 2h in the clinical exp. lab.

Exclusion Criteria:

* Acute airway infection
* History of asthma
* Smokers
* Pregnancy
* Abnormal lab. screen with liver function tests, Creat./BUN, CBC, blood glucose
* Anxiety or mood disorder
* Any chronic disease (incl. lung \& heart disease, cancer, endocrine disorder)
* Mental retardation

Primary outcomes:
measure: Dyspnea score
timeFrame: Minutes
measure: Variability of systolic blood pressure
timeFrame: Minutes
Secondary outcomes:
Other outcomes:
Locations:
city: Wuppertal
country: Germany
facility: HELIOS-Klinikum / University of Witten/Herdecke
state: NRW
Study officials:
affiliation: University of Witten/Herdecke
name: Hubert Trubel, MD
role: PRINCIPAL_INVESTIGATOR
References:
citation: Truebel H, Wuester S, Boehme P, Doll H, Schmiedl S, Szymanski J, Langer T, Ostermann T, Cysarz D, Thuermann P. A proof-of-concept trial of HELIOX with different fractions of helium in a human study modeling upper airway obstruction. Eur J Appl Physiol. 2019 May;119(5):1253-1260. doi: 10.1007/s00421-019-04116-7. Epub 2019 Mar 8.