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| Name | Class |
|---|---|
| Medical University Innsbruck | OTHER |
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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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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Winter snow | Experimental | First test series breathing in dry snow in winter |
|
| Intermediate snow | Experimental | Second test series breathing in dry/wet snow in intermediate season |
|
| Spring snow | Experimental | Third test series breathing in very wet snow in spring |
|
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Breathing in snow | Other | Breathing in snow with different physical properties |
|
| Measure | Description | Time Frame |
|---|---|---|
| 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 |
| Measure | Description | Time Frame |
|---|---|---|
| EtCO2 (mmHg) | 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 |
| Cause of interruption |
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Inclusion Criteria:
Exclusion Criteria:
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| Name | Affiliation | Role |
|---|---|---|
| Giacomo Strapazzon, MD PhD | Eurac Research | Study Director |
| Hermann Brugger, MD | Eurac Research | Study Director |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Institute of Mountain Emergency Medicine, Eurac Research | Bolzano | Bz | 39100 | Italy |
| PubMed Identifier | Type | Citation | Retractions |
|---|---|---|---|
| 12867313 | Background | 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. | |
| 21422139 | 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. |
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| ID | Term |
|---|---|
| D012131 | Respiratory Insufficiency |
| ID | Term |
|---|---|
| D012120 | Respiration Disorders |
| D012140 | Respiratory Tract Diseases |
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| ID | Term |
|---|---|
| D012119 | Respiration |
| D012914 | Snow |
| ID | Term |
|---|---|
| D012143 | Respiratory Physiological Phenomena |
| D002943 | Circulatory and Respiratory Physiological Phenomena |
| D055907 | Climatic Processes |
| D055669 | Ecological and Environmental Phenomena |
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SpO2 <75% or subjectives symptoms due to hypercapnia (like dyspnea, dizziness, and headache) |
| Timepoint immediately before interruption of snow-breathing phase (max 30min) |
| VE (L/min) | 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 |
| rSO2 (%) | 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 |
| D001686 | Biological Phenomena |
| D014887 | Weather |
| D001272 | Atmosphere |
| D004777 | Environment |
| D008685 | Meteorological Concepts |
| D004778 | Environment and Public Health |