Snow Physical Properties and Human Ventilatory Response

Institute of Mountain Emergency Medicine

Status: Completed

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

Treatments: Other: Breathing in snow

Study type: Interventional

Funder types: Other

Identifiers

NCT03082105

V/16/13

Details and patient eligibility

About

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).

Enrollment: 12 patients

Sex: All

Ages: 18+ years old

Volunteers: Accepts Healthy Volunteers

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.

Trial design

Primary purpose: Basic Science

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: Double Blind

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12 participants in 3 patient groups

Winter snow

Experimental group

Description:

First test series breathing in dry snow in winter

Treatment:

Other: Breathing in snow

Intermediate snow

Experimental group

Description:

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

Treatment:

Other: Breathing in snow

Spring snow

Experimental group

Description:

Third test series breathing in very wet snow in spring

Treatment:

Other: Breathing in snow