Physiological effects of providing supplemental air for avalanche victims. A randomised trial

Brattebø, Guttorm; Østerås, Øyvind; Aßmus, Jörg; Irusta, Unai; Aramendi, Elisabete; Mydske, Sigurd; Skaalhegg, Tore; Skaiaa, Sven Christjar; Thomassen, Øyvind

doi:10.1016/j.resuscitation.2022.01.007

Cited by 6 publications

(7 citation statements)

References 25 publications

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“…The study types were 45 retrospective studies (38%), 44 case reports or case series (37%), 18 prospective studies, including seven randomised-controlled studies with volunteers [26][27][28][29][30][31][32] (15%), eight descriptions of mass casualty incidents (7%), three observational studies (surveys) of avalanche victims (2%) and two prospective studies on animals (2%).…”

Section: Resultsmentioning

confidence: 99%

On-site treatment of avalanche victims: Scoping review and 2023 recommendations of the international commission for mountain emergency medicine (ICAR MedCom)

Pasquier¹,

Strapazzon²,

Kottmann³

et al. 2023

Resuscitation

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Section: Resultsmentioning

confidence: 99%

On-site treatment of avalanche victims: Scoping review and 2023 recommendations of the international commission for mountain emergency medicine (ICAR MedCom)

Pasquier¹,

Strapazzon²,

Kottmann³

et al. 2023

Resuscitation

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“…This means that rapid brief changes in oxygen saturation are suppressed, as in the hospital settings they are usually caused by motion artifacts, bad connections or poor contact [34,35]. However, these rapid changes in SpO 2 are typical for outdoor breathing experiments in the simulated avalanche snow [8][9][10][11][12][13][14][15] as well as in breath-hold divers [7].…”

Section: Discussionmentioning

confidence: 99%

“…Moreover, the levels of oxygen (O 2 ) and carbon dioxide (CO 2 ) in the organism often serve as study endpoints. The limits are set at different values; for pulse oximetry from SpO 2 75% [8][9][10] to 85% [11,12], or even 88% [13] and for end-tidal carbon dioxide (EtCO 2 ) at 8% [10,14], or 60 mmHg [15].…”

Section: Introductionmentioning

confidence: 99%

Pulse Oximeter Performance during Rapid Desaturation

Horáková

Roubík

2022

Sensors

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The reliability of pulse oximetry is crucial, especially in cases of rapid changes in body oxygenation. In order to evaluate the performance of pulse oximeters during rapidly developing short periods of concurrent hypoxemia and hypercapnia, 13 healthy volunteers underwent 3 breathing phases during outdoor experiments (39 phases in total), monitored simultaneously by five different pulse oximeters. A significant incongruity in values displayed by the tested pulse oximeters was observed, even when the accuracy declared by the manufacturers were considered. In 28.2% of breathing phases, the five used devices did not show any congruent values. The longest uninterrupted congruent period formed 74.4% of total recorded time. Moreover, the congruent periods were rarely observed during the critical desaturation phase of the experiment. The time difference between the moments when the first and the last pulse oximeter showed the typical study endpoint values of SpO2 85% and 75% was 32.1 ± 23.6 s and 24.7 ± 19.3 s, respectively. These results suggest that SpO2 might not be a reliable parameter as a study endpoint, or more importantly as a safety limit in outdoor experiments. In the design of future studies, more parameters and continuous clinical assessment should be included.

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“…This increased ventilatory drive was possibly induced by an increased CO 2 content in the air pocket, stimulating V ˙E, favoring quicker O 2 consumption and contributing to further CO 2 accumulation. To our knowledge, 1 other study 14 has been performed with supine participants breathing into an artificial air pocket, but with the body out of the snow. Similar to our trial, a study by Wik et al 14 found that in the control trial, VT and V ˙E increased significantly, with a lower FIO 2 and a higher FICO 2 .…”

Section: Jama Network Open | Emergency Medicinementioning

confidence: 99%

“…To our knowledge, 1 other study 14 has been performed with supine participants breathing into an artificial air pocket, but with the body out of the snow. Similar to our trial, a study by Wik et al 14 found that in the control trial, VT and V ˙E increased significantly, with a lower FIO 2 and a higher FICO 2 . The faster decrease in FIO 2 might increase risk of asphyxiation.…”

Section: Jama Network Open | Emergency Medicinementioning

confidence: 99%

Comparative Effectiveness of an Artificial Air Pocket Device to Delay Asphyxiation in Supine Individuals Critically Buried in Avalanche Debris

Strapazzon,

Rauch,

Malacrida

et al. 2023

JAMA Netw Open

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ImportanceApproximately 70% of individuals critically buried in avalanche debris die within 35 minutes as a result of asphyxial cardiac arrest. An artificial air-pocket device (AAPD) that separates inhaled air from exhaled air may delay the onset of severe hypoxemia and eventual asphyxia during snow burial.ObjectiveTo investigate the efficacy of a new AAPD during snow burial in a supine position.Design, Setting, and ParticipantsThis comparative effectiveness trial was performed in winter 2016 with data analysis in November 2016 and November 2022. Each trial used a simulated critical avalanche burial scenario, in which a trough was dug in a snow pile and an additional air pocket of 0.5 L volume was punched into the lateral wall for each control trial. All participants were buried in a supine position. Trials could be voluntarily terminated at any time, with a maximum length of 60 minutes; trials were automatically terminated if the participant’s peripheral oxygen saturation (Spo2) dropped to less than 84%.ExposuresEach participant conducted 2 trials, one in which they breathed into the AAPD (intervention trial) and the other in which they breathed into the prepared air pocket (control trial).Main Outcomes and MeasuresMeasurements included Spo2, cerebral oxygenation, ventilatory parameters, respiratory gas concentrations, and visual-analogue scales. Kaplan-Meier survival curves and rank test for matched survival data were used to analyze the total burial time in each trial.ResultsA total of 13 volunteers (9 men; mean [SD] age, 33 [8] years) were exposed to the intervention and control trials. Intervention trials were terminated less often (2 of 13 trials) as a result of hypoxemia than control trials (11 of 12 trials). Similarly, survival curves showed a longer duration of burial in the intervention compared with the control trials for the time to reach an Spo2 less than 84% (rank test for matched survival data: P = .003). The intervention trials, compared with the control trials, also had slower rates of decrease in fraction of inspired oxygen (mean [SD] rate, −0.8 [0.4] %/min vs −2.2 [1.2] %/min) and of increase in fraction of inspired carbon dioxide (mean [SD] rate, 0.5 [0.3] %/min vs 1.4 [0.6] %/min) and expired ventilation per minute (mean [SD] rate, 0.5 [1.0] L/min2 vs 3.9 [2.6] L/min2).Conclusions and RelevanceThis comparative effectiveness trial found that the new AAPD was associated with delaying the development of hypoxemia and hypercapnia in supine participants in a critical burial scenario. Use of the AAPD may allow a longer burial time before asphyxial cardiac arrest, which might allow longer times for successful rescue by companions or by prehospital emergency medical services.

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Physiological effects of providing supplemental air for avalanche victims. A randomised trial

Cited by 6 publications

References 25 publications

On-site treatment of avalanche victims: Scoping review and 2023 recommendations of the international commission for mountain emergency medicine (ICAR MedCom)

On-site treatment of avalanche victims: Scoping review and 2023 recommendations of the international commission for mountain emergency medicine (ICAR MedCom)

Pulse Oximeter Performance during Rapid Desaturation

Comparative Effectiveness of an Artificial Air Pocket Device to Delay Asphyxiation in Supine Individuals Critically Buried in Avalanche Debris

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