Programme Hospitalier Recherche Clinique, Institut Pasteur, Inserm, French Public Health Agency.

IntroductionPre-hospital triage is a key element in a trauma system that aims to admit patients to the most suitable trauma center, and may decrease intra-hospital mortality. We evaluated the performance of a pre-hospital procedure in a regional trauma system through measurements of the quality of pre-hospital medical assessment and the efficacy of a triage protocol.MethodsOur regional trauma system included 13 hospitals categorized as Level I, II or III trauma centers according to their technical facilities. Each patient was graded A, B or C by an emergency physician, according to the seriousness of their injuries at presentation on scene. The triage was performed according to this grading and the categorization of centers. This study is a registry analysis of a three-year period (2009 to 2011).ResultsOf the 3,428 studied patients, 2,572 were graded using the pre-hospital grading system (Graded group). The pre-hospital gradation was closely related with injury severity score (ISS) and intra-hospital mortality rate. The triage protocol had a sensitivity of 92% (95% confidence interval (CI) 90% to 93%) and a specificity of 41% (95% CI 39% to 44%) to predict adequate admission of patients with ISS more than 15. A total of 856 patients were not graded at the scene (Non-graded group). Undertriage rate was significantly reduced in the Graded group compared with the Non-graded group, with a relative risk of 0.47 (95% CI 0.40 to 0.56) according to the definition of the American College of Surgeons Committee on Trauma (P <0.001). Where adjusted for trauma severity, the expected mortality rate at discharge from hospital was higher than observed mortality, with a difference of +2.0% (95% CI 1.4 to 2.6%; P <0.01).ConclusionsImplementation of a regional trauma system with a pre-hospital triage procedure was effective in detecting severe trauma patients and in lowering the rate of pre-hospital undertriage. A beneficial effect on outcome of such an organization is suggested.Electronic supplementary materialThe online version of this article (doi:10.1186/s13054-015-0835-7) contains supplementary material, which is available to authorized users.

The study evaluated seven intensive care unit (ICU) ventilators (Veolar FT, Galileo, Evita 2, Evita 4, Servo 900C, Servo 300, Nellcor Puritan Bennett 7200 Series) with helium-oxygen (HeO 2 ), using a lung model, to develop correction factors for the safe use of HeO 2 . A 70:28 helium-O 2 mixture (heliox) replaced air and combined with O 2 (HeO 2 ). Theoretical impact of HeO 2 on inspiratory valves and gas mixing was computed. True fraction of inspired oxygen (F I O2 del) was compared with fraction of inspired oxygen (F I O2 ) set on the ventilator (F I O2 set). True tidal volume (V T del) was compared with V T set on the ventilator (V T set) in volume control and with control V T del at F I O2 1.0 in pressure control. F I O2 del minimally exceeded F I O2 set ( р 5%) except with the 7200 Series (F I O2 del Ͼ F I O2 set by 125%). In volume control, with the Veolar FT, Galileo, Evita 2, and Servo 900C, V T del Ͼ V T set, with the 7200 Series V T del Ͻ V T set (linear relationship, magnitude of discrepancy inversely related to F I O2 set). With the Evita 4, V T del Ͼ V T set (nonlinear relationship), whereas with the Servo 300 V T del ϭ V T set. In pressure control, V T del was identical to control measurements, except with the 7200 Series (ventilator malfunction). Correction factors were developed that can be applied to most ventilators. Tassaux D, Jolliet P, Thouret J-M, Roeseler J, Dorne R, Chevrolet J-C. Calibration of seven ICU ventilators for mechanical ventilation with helium-oxygen mixtures. AM J RESPIR CRIT CARE MED 1999;160:22-32.Reducing the density of inspired gas by using a mixture of helium and O 2 (HeO 2 ) instead of air and O 2 (airO 2 ) can be beneficial in spontaneously breathing patients with upper or lower airway obstructive disease (1, 2). In acute severe asthma, breathing HeO 2 increases peak expiratory flow and Pa O2 , and decreases pulsus paradoxus, Pa CO 2 , and dyspnea (3-5). In patients with COPD, breathing HeO 2 increases expiratory flow and decreases airway resistance (6, 7). Moreover, evidence suggests that these favorable effects can also be obtained during mechanical ventilation in status asthmaticus (8) and in patients with COPD (9, 10), even though the data are still preliminary in the latter patient population, and await confirmation by prospective studies. However, the physical properties of helium could interfere with several key ventilator functions such as gas mixing, inspiratory and expiratory valve accuracy, flow measurement, triggering, positive end-expiratory pressure (PEEP), and automatic leakage compensation, thus raising issues regarding the accuracy of ventilator performance (11) and patient safety.The present study was designed to test the performances of seven standard intensive care unit (ICU) ventilators available in Europe during HeO 2 utilization, compared with theoretical predictions based on the physical properties of helium, and to develop correction factors (12) to ensure the safe use of HeO 2 during mechanical ventilation.

In decompensated COPD patients, noninvasive pressure support ventilation with helium:oxygen reduced dyspnea and PaCO2 more than air:oxygen, modified respiratory cycle times, and did not modify systemic blood pressure. These effects could prove beneficial in COPD patients with severe acute respiratory failure and might reduce the need for endotracheal intubation.