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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.

Background Repeat surgery of the chronically dissected aorta following repair of a Type-A acute aortic dissection (AAD) still represents a challenge. The proposed surgical options are as follows: (1) staged procedure with elephant trunk (ET) technique, (2) traditional frozen elephant trunk (FET) intervention, and (3) beating heart cerebral vessel debranching followed by thoracic endovascular aortic repair (TEVAR). However, a marked enlargement of the proximal descending thoracic aorta might make it difficult to perform FET/ET intervention. Furthermore, because in conventional surgery for AAD, a prosthetic graft replacement is generally limited to the ascending aorta, and in repeat surgery, this short Dacron graft rarely provides enough room to allow a beating heart cerebral vessel debranching and obtaining a reliable landing zone for the implantation of a firmly anchored stent graft. Methods We retrospectively reviewed all the five consecutive patients treated in our institution, between 2014 and 2017, for chronic aortic dissection after successful surgical treatment of acute Type-A aortic dissection with graft replacement limited to the ascending aorta. The five patients underwent repair utilizing a modified FET technique with total aortic arch and upper descending aorta exclusion without touching the native dissected aorta. Results No early- or midterm mortality was observed. Mean time interval between the initial and the reoperative procedure was 26 months (range, 3–80 months). No patient had a minor/major neurologic event. Mean circulatory arrest time was 16 minutes (range, 11–25 minutes). Mean follow-up time was 22 months (range, 9–42 months). Conclusions We report our initial experience with a modified FET technique realized by anastomosing the stent graft with the previously implanted ascending aortic graft in Hishimaru's zone 0 and by rerouting all cerebral vessels without “touching” the native chronically dissected aorta. A larger number of patients and a longer follow-up will be required to confirm these initial encouraging results.

Brustia, Raffaele, Giulia Enrione, Bruna Catuzzo, Luca Cavoretto, Massimo Pesenti Compagnoni, Enrico Visetti, Emmanuel Cauchy, Stefanie Ziegler, and Guido Giardini. Results of a prospective observational study on mountaineering emergencies in Western Alps: mind your head. High Alt Med Biol. 17:116-121, 2016.-In the northern Italian district Valle d'Aosta district during winter and summer season the population can increase up to 170% of the resident population. A prospective monocentric observational registry was held to obtain a precise picture of seasonal mountain-related medical and traumatic major events.From 1st January 2012 to 31st December 2013 all patients admitted to the Aosta Regional Hospital Emergency Room for any event occurred above 2500 m were screened: all those affected by High Altitude Illness, Acute Illness in High Altitude, Trauma, or Cold disease were prospectively included. Activity incidence rate is expressed as the occurrence of mountain-related events per 1000 hours of mountain activity. Event Incidence rate is expressed as the occurrence of new cases per 1000 hours of mountain activity.Two hundred two patients were included during the study period. Trauma (65.1% vs. 24.6%, p 0.001) and head commotive injury (48.1% vs. 15.1%, p 0.001) were more frequent during winter compared to the summer season. High altitude illness (36.9% vs. 9.3%, p 0.001) and cold pathologies (15.1% vs. 0.1%, p 0.001) occurred more frequently in summer than in winter. Patients (51.4%) were immediately discharged from emergency room, 8.4% after a 24-hour observation period, and 30.6% required hospitalization. During summer, the event risk is 0.013 per person and 1000 hours of mountain activity, while in winter, event risk amounts to 0.005 per person and 1000 hours of mountain activity.High altitude medical events or trauma represent1% of pathologies observed in the emergency room department of a mountain district in the western Alps. Head commotive injury is the most observed mountain-related event in high altitude, in winter and during ski practice. High altitude illness and cold injuries are observed more frequently in summer, during trekking or climbing activities.