Efficacy and Pathophysiological Implications of a New Asphyxiation Delaying Device

Study Overview
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Brief Summary
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Survival of fully buried avalanche victims depends in major part on a triad of hypoxia, hypercapnia, and hypothermia and therefore decreases rapidly after complete burial. Besides optimizing companion rescue, which still today and even by trained people often takes more than 15 minutes to the extraction of an avalanche victim, prolonging the ability to breath after critical avalanche burial increases survival probability by giving rescuers more time to find and unbury avalanche victims. Based on previous research, the Norwegian company Safeback SE (Bergen, Norway) developed a new non-medical device using an innovative functional principle. The device, called the Safeback SBX (Safeback SE, Bergen, Norway), should make it possible to prevent asphyxia by delivering fresh air to the air pocket. Company claims to achieve a prolongation of survival up to over 60 minutes, giving companion rescuers as well as professional rescue teams more time to get access to the victim. Technical tests conducted by the developing company already provided some promising results regarding the general functioning. However, this study is needed to provide the scientific evidence of the effectiveness and influence on physiologic parameters buried in snow debris humans under realistic conditions.

Official Title
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A New Device to Delay Asphyxiation in Subjects Critically Buried in Avalanche Debris: Efficacy and Pathophysiological Implications

Conditions
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Avalanche, Landslide, or Mudslide, Asphyxia; Immersion

Intervention / Treatment
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* Device: Safeback SBX
* Device: Sham device


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: - healthy ASA I subjects Exclusion Criteria: ASA class II or higher chronic high degree cardiovascular or pulmonary disease claustrophobia psychiatric or neurological disease long-term medication pregnant woman no informed consent history of fever or serious cough in the past two weeks current Covid-19 symptoms or recently tested positive for Covid-19 body temperature ≥ 37.5°on test days.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Intervention<br>Active Device | Device: Safeback SBX<br>* The intervention consists in the test of the active device.<br>|
| Sham Comparator: Control<br>Sham Device | Device: Sham device<br>* The intervention consists in a similar device to that emits same noise but does not deliver airflow.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Time limit | Reaching a predefined time limit (min) | From baseline up to 60 minutes | 
| Physiological threshold | Time to reach a SpO2 threshold up to <75% (min) | From baseline up to 60 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| End-tidal CO2 (EtCO2) | Changes in EtCO2 (mmHg) | Changes from baseline (measurement at 0 min) -> snow-breathing phase (5min, 15min, and timepoint immediately before interruption [up to 60 min) (countinuous monitoring) | 
| Minute ventilation (VE) | Changes in VE (L/min) | Changes from baseline (measurement at 0 min) -> snow-breathing phase (5min, 15min, and timepoint immediately before interruption [up to 60 min) (countinuous monitoring) | 
| Cerebral Regional Oxygen Saturation (rSO2) | Changes in rSO2 (%) | Changes from baseline (measurement at 0 min) -> snow-breathing phase (5min, 15min, and timepoint immediately before interruption [up to 60 min) (countinuous monitoring) | 
| NASA-task load index (NASA-TLX) questionnaire (perceived workload) | Changes in NASA-task load index (NASA-TLX) questionnaire (numerical scale) | Change from basal measurement (before hypoxia exposure) to post-exposure measurement (after hypoxia exposure - up to 60 min) | 
| Reactive oxygen species - ROS | Changes in ROS in saliva samples (μmol/min) | Change from basal measurement (before hypoxia exposure) to post-exposure measurement (after hypoxia exposure - up to 60 min) | 
| Total antioxidant capacity - TAC | Changes in TAC in saliva samples (mM) | Change from basal measurement (before hypoxia exposure) to post-exposure measurement (after hypoxia exposure - up to 60 min) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Avalanche, Avalanche burial, Cardiac arrest, Asphyxia, Emergengy medicine