Hypercapnia and Gas Exchange Under the Avalanche Snow Model (HyperAvaSM)

Study Overview
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Brief Summary
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The aim of the study is to investigate respiratory parameters of a person in the simulated avalanche snow and consequent use of the measured data for development of a mathematical-physical model of breathing during increasing hypercapnia in the avalanche.

Detailed Description
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The study is a part of a university research project aimed at studying physiological conditions and development of breathing parameters of a person breathing in the simulated avalanche snow. Presence of an air pocket and its size play an important role in survival of victims buried in the avalanche snow. Even small air pockets facilitate breathing, yet they do not provide a significant amount of fresh air for breathing. The investigators hypothesize that the size of the air pocket significantly affects the airflow resistance and work of breathing. The aim of the study is to investigate the effect of the air pocket volume on gas exchange and work of breathing in subjects breathing into the simulated avalanche snow and to test, whether it is possible to breathe with zero air pocket.

Official Title
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Hypercapnia and Gas Exchange Under the Simulated Avalanche Snow

Conditions
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Accident Caused by Snow Avalanche

Intervention / Treatment
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* Other: Breathing in the simulated avalanche snow.
* Device: air pocket


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Participants were volunteers from the Czech Army forces, studying at the Military Department of the Faculty of Physical Education and Sport, Charles University in Prague. All subjects were healthy and fit, classified as ASA I, all without a smoking history. The volunteers were highly motivated to participate in the experiment. The entrance examination, completed before the start of the study, included these tests: electrocardiography, blood pressure, spirometry, and assessment of the health conditions and family anamnesis by a physician with a specialty in anesthesia and critical care. Exclusion Criteria: The exclusion criteria were Tiffeneau Index less than 0.70 and any cardiovascular or respiratory condition.

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 30 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Intervention Model: Single Group Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: air pocket<br>Breathing in the simulated avalanche snow. | Other: Breathing in the simulated avalanche snow.<br>* Breathing in the simulated avalanche snow with zero air pocket and one-liter air pocket.<br>Device: air pocket<br>* Zero air pocket or one-liter air pocket in the snow.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The length of breathing | Time to termination of the breathing experiment due to the decision of the subject, or determined by high End-Tidal CO2 value or by the order by the clinician assessing the health status of the subjects. | Continuously within 30 minute interval from the beginning of the breathing experiment |