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Completed

NCT Number: NCT03082105

Snow Physical Properties and Human Ventilatory Response

Sufficient oxygenation is critical for completely buried avalanche victims to avoid life-threatening consequences during hypoxic exposure. Snow contains a remarkable capacity to maintain air availability; it was suspected that the snow physical properties affect the development of hypoxia and hypercapnia. The aim of this study was to evaluate the influence of different snow physical properties on the development of hypoxia and hypercapnia in subjects breathing into an artificial air pocket in snow. Twelve male healthy subjects breathed through an airtight face-mask and 40cm tube into an artificial air pocket of 4L. Every subject performed three tests on different days with varying snow characteristics. Symptoms, gas and cardiovascular parameters were monitored up to 30min. Tests were interrupted at SpO2 <75% (primary endpoint); or due to subjective symptoms like dyspnea, dizziness, and headache (i.e. related to hypercapnia). Snow density was assessed via standard methods and micro-computed tomography (CT) analysis, and permeability and penetration with the snow micro-penetrometer (SMP).

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Key information

Conditions

Hypoxic Respiratory Failure Avalanche Burial Hypercapnic Respiratory Failure Respiration Disorders Respiratory Insufficiency Respiratory Tract Diseases Snow Physical Properties

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Institute of Mountain Emergency Medicine, Eurac Research

Bolzano, Bz, 39100, Italy

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Healthy volunteers with an age above 18yr-old, physically active.
  • Volunteers have been informed and have signed consent.

Exclusion criteria

  • Lack of consent.
  • Chronic previous illness of the respiratory tract or of the cardiovascular system.
  • Acute disease at or immediately prior to the test (eg, flu-like infection, fever of unknown origin).
  • Eurac employees.

Treatment and study plan

Breathing in snow

Other

Breathing in snow with different physical properties

Primary outcomes

  1. SpO2 (%)

    Time frame: Changes from baseline (measurement at 0min) -> snow-breathing phase (5min, 15min, and timepoint immediately before interruption of snow-breathing phase [max 30min]) -> 2.5min and 5min after snow-breathing phase

    Continuous monitoring

Secondary outcomes

  1. EtCO2 (mmHg)

    Time frame: Changes from baseline (measurement at 0min) -> snow-breathing phase (5min, 15min, and timepoint immediately before interruption of snow-breathing phase [max 30min]) -> 2.5min and 5min after snow-breathing phase

    Continuous monitoring

  2. Cause of interruption

    Time frame: Timepoint immediately before interruption of snow-breathing phase (max 30min)

    SpO2 <75% or subjectives symptoms due to hypercapnia (like dyspnea, dizziness, and headache)

  3. VE (L/min)

    Time frame: Changes from baseline (measurement at 0min) -> snow-breathing phase (5min, 15min, and timepoint immediately before interruption of snow-breathing phase [max 30min]) -> 2.5min and 5min after snow-breathing phase

    Continuous monitoring

  4. rSO2 (%)

    Time frame: Changes from baseline (measurement at 0min) -> snow-breathing phase (5min, 15min, and timepoint immediately before interruption of snow-breathing phase [max 30min]) -> 2.5min and 5min after snow-breathing phase

    Continuous monitoring

Sponsors and collaborators

Lead sponsor

Institute of Mountain Emergency Medicine

Other

Collaborators

  • Medical University Innsbruck

Registry information

Official study title

Evaluation of Air Pocket Factors That Contribute to the Development of Hypoxia and Hypercapnia

Important dates

Study start
2013
Primary completion
2014
Study completion
2014
First posted
Mar 17, 2017
Registry last updated
Mar 17, 2017

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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