Since Bert (1878) and Barcroft (1925), studies on hypoxia are realized by lowering ambient O(2) partial pressure (PO(2)) either by barometric pressure reduction (hypobaric hypoxia HH) or by lowering the O(2) fraction (normobaric hypoxia NH). Today, a question is still debated: "are there any physiological differences between HH and NH for the same ambient PO(2)?" Since published studies are scarce and controversial, we submitted 18 subjects in a random order to a 40-min HH test and to a 40-min NH test at an ambient PO(2) equal to 120 hPa (4500 m). Cardioventilatory variables [breathing frequency (f), tidal volume (V(t)), minute ventilation (V(E)), O(2) and CO(2) end-tidal fractions or pressures (FET(O2) and FET(CO2) or PET(O2) and PET(CO2) respectively), heart rate (HR) and O(2) arterial saturation by pulse oxymetry (SpO(2))] were measured throughout the tests. At the end of the tests, arterial blood samples were taken to measure arterial blood gases [O(2) and CO(2) arterial partial pressures ( Pa(O2) and Pa(CO2)), pH and O(2) arterial saturation (SaO(2))]. Results show that during HH compared to NH, f is greater (P

The association between total prehospital time and mortality in physician-staffed trauma systems remains uncertain.OBJECTIVE To describe the association of total prehospital time and in-hospital mortality in prehospital, physician-staffed trauma systems in France, with the hypothesis that total prehospital time is associated with increased mortality. DESIGN, SETTING, AND PARTICIPANTSThis cohort study was conducted from January 2009 to December 2016. Data for this study were derived from 2 distinct regional trauma registries in France (1 urban and 1 rural) that both have a physician-staffed emergency medical service. Consecutive adult trauma patients admitted to either of the regional trauma referral centers during the study period were included. Data analysis took place from March 2018 to September 2018. MAIN OUTCOMES AND MEASURESThe association between death and prehospital time was assessed with a multivariable model adjusted with confounders. Total prehospital time was the primary exposure variable, recorded as the time from the arrival of the physician-led prehospital care team on scene to the arrival at the hospital. The main outcome of interest was all-cause in-hospital mortality.RESULTS A total of 10 216 patients were included (mean [SD] age, 41 [18] years; 7937 men [78.3%]) affected by predominantly nonpenetrating injuries (9265 [91.5%]), with a mean (SD) Injury Severity Score of 17 ( 14) points. Of the patients, 6737 (66.5%) had at least 1 body region with an Abbreviated Injury Scale score of 3 or more. A total of 1259 patients (12.4%) presented in shock (with systolic pressure <90 mm Hg) and 2724 (26.9%) with severe head injury (Abbreviated Injury Scale score Ն3 points). On unadjusted analysis, increasing prehospital times (in 30-minute categories) were associated with a markedly and constant increase in the risk of in-hospital death. The odds of death increased by 9% for each 10-minute increase in prehospital time (odds ratio, 1.09 [95% CI, 1.07-1.11]) and after adjustment by 4% (odds ratio, 1.04 [95% CI, 1.01-1.07]). CONCLUSIONS AND RELEVANCEIn this study, an increase in total prehospital time was associated with increasing in-hospital all-cause mortality in trauma patients at a physician-staffed emergency medical system, after adjustment for case complexity. Prehospital time is a management objective in analogy to physiological targets. These findings plead for a further streamlining of prehospital trauma care and the need to define the optimal intervention-to-time ratio.

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BACKGROUND French military operations in the Sahel conducted since 2013 over more than 5 million square kilometers have challenged the French Military Health Service with specific problems in prolonged field care. STUDY DESIGN AND METHODS To describe these challenges, we retrospectively analyzed the prehospital data from the first 5 years of these operations within a delimited area. RESULTS One hundred eighty‐three servicemen of different nationalities were evacuated, mainly as a result of explosions (73.2%) or gunshots (21.9%). Their mean number evacuation was 2.2 (minimum, 1; maximum, 8) per medical evacuation with a direct evacuation from the field to a Role 2 medical treatment facility (MTF) for 62% of them. For the highest‐priority casualties (N = 46), the median time [interquartile range] from injury to a Role 2 MTF was 130 minutes [70 minutes to 252 minutes], exceeding 120 minutes in 57% of cases and 240 minutes in 26%. The most frequent out‐of‐hospital medical interventions were external hemostasis, airway and hemopneumothorax management, hypotensive resuscitation, analgesia, immobilization, and antibiotic administration. Prehospital transfusion (RBCs and/or lyophilized plasma) was started three times in the field, two times during helicopter medical evacuation, and five times in tactical fixed wing medical aircraft. Lyophilized plasma was confirmed to be particularly suitable in these settings. One of the specific issues involved in lengthy prehospital time was the importance to reassess and convert tourniquets prior to Role 2 MTF admission. CONCLUSION Main challenges identified include reducing evacuation times as much as possible, preserving ground deployment of sufficiently trained medics and medical teams, optimization of transfusion strategies, and strengthening specific prolonged field care equipment and training.

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