Snow Physical Properties and Human Ventilatory Response

Hypercapnic Respiratory Failure Clinical Trial

Official title:

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

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT03082105
• Other study ID #: V/16/13
• Status: Completed
• Phase: N/A
• First received: March 8, 2017
• Last updated: March 10, 2017
• Start date: December 1, 2013
• Est. completion date: March 9, 2014

Study information

• Verified date: March 2017
• Source: Institute of Mountain Emergency Medicine
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial 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).

Recruitment information / eligibility

• Status: Completed
• Enrollment: 12
• Est. completion date: March 9, 2014
• Est. primary completion date: March 9, 2014
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 18 Years and older

Eligibility

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.

Related Conditions & MeSH terms

• Avalanche Burial
• Hypercapnia
• Hypercapnic Respiratory Failure
• Hypoxic Respiratory Failure
• Respiratory Insufficiency
• Snow Physical Properties

Intervention

Other:
• Breathing in snow
Breathing in snow with different physical properties

Locations

Country	Name	City	State
Italy	Institute of Mountain Emergency Medicine, Eurac Research	Bolzano	Bz

Sponsors (2)

Lead Sponsor	Collaborator
Institute of Mountain Emergency Medicine	Medical University Innsbruck

Country where clinical trial is conducted

Italy, 

References & 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. — View Citation

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. — View Citation

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	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	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
Secondary	Cause of interruption	SpO2 <75% or subjectives symptoms due to hypercapnia (like dyspnea, dizziness, and headache)	Timepoint immediately before interruption of snow-breathing phase (max 30min)
Secondary	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
Secondary	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