Snow Physical Properties and Human Ventilatory Response

NCT03082105 | Completed

• 1 other identifier: V/16/13
• Study Type: interventional
• Target: 12
• Locations: 1 country
• Sites: 1

Brief Summary

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).

Conditions

Hypoxic Respiratory Failure; Hypercapnic Respiratory Failure; Avalanche Burial; Snow Physical Properties

Outcome Measures

Primary Outcomes (1)

• SpO2 (%)

  Continuous monitoring

  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

Secondary Outcomes (4)

• EtCO2 (mmHg)

  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

• Cause of interruption

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

• VE (L/min)

  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

• rSO2 (%)

  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

Study Arms (3)

Winter snow

EXPERIMENTAL

First test series breathing in dry snow in winter

Other: Breathing in snow

Intermediate snow

EXPERIMENTAL

Second test series breathing in dry/wet snow in intermediate season

Other: Breathing in snow

Spring snow

EXPERIMENTAL

Third test series breathing in very wet snow in spring

Other: Breathing in snow

Interventions

Breathing in snow OTHER

Breathing in snow with different physical properties

Intermediate snow; Spring snow; Winter snow

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

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

You may not qualify if:

• 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.

Sponsors & Collaborators

• Institute of Mountain Emergency Medicine: lead
• Medical University Innsbruck: collaborator

Study Sites (1)

Institute of Mountain Emergency Medicine, Eurac Research

Bolzano, Bz, 39100, Italy

Location

Related Publications (2)

• Brugger H, Sumann G, Meister R, Adler-Kastner L, Mair P, Gunga HC, Schobersberger W, Falk M. Hypoxia and hypercapnia during respiration into an artificial air pocket in snow: implications for avalanche survival. Resuscitation. 2003 Jul;58(1):81-8. doi: 10.1016/s0300-9572(03)00113-8.

  PMID: 12867313 BACKGROUND

• Haegeli P, Falk M, Brugger H, Etter HJ, Boyd J. Comparison of avalanche survival patterns in Canada and Switzerland. CMAJ. 2011 Apr 19;183(7):789-95. doi: 10.1503/cmaj.101435. Epub 2011 Mar 21.

  PMID: 21422139 BACKGROUND

MeSH Terms

Conditions

Respiratory Insufficiency

Interventions

Respiration; Snow

Condition Hierarchy (Ancestors)

Respiration Disorders; Respiratory Tract Diseases

Intervention Hierarchy (Ancestors)

Respiratory Physiological Phenomena; Circulatory and Respiratory Physiological Phenomena; Climatic Processes; Ecological and Environmental Phenomena; Biological Phenomena; Weather; Atmosphere; Environment; Meteorological Concepts; Environment and Public Health

Study Officials

• Giacomo Strapazzon, MD PhD

  Eurac Research

  STUDY DIRECTOR

• Hermann Brugger, MD

  Eurac Research

  STUDY DIRECTOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, INVESTIGATOR
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: March 8, 2017
• First Posted: March 17, 2017
• Study Start: December 1, 2013
• Primary Completion: March 9, 2014
• Study Completion: March 9, 2014
• Last Updated: March 17, 2017

Record last verified: 2017-03

Data Sharing

• IPD Sharing: Will not share

Locations

IT (1)