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Background Although acute respiratory distress syndrome (ARDS) is associated with high mortality, its direct causal link with death is unclear. Clarifying this link is important to justify costly research on prevention of ARDS. Objective To estimate the attributable mortality, if any, of ARDS. Design First, we performed a systematic review and meta-analysis of observational studies reporting mortality of critically ill patients with and without ARDS matched for underlying risk factor. Next, we conducted a survival analysis of prospectively collected patient-level data from subjects enrolled in three intensive care unit (ICU) cohorts to estimate the attributable mortality of critically ill septic patients with and without ARDS using a novel causal inference method. Results In the meta-analysis, 44 studies (47 cohorts) involving 56 081 critically ill patients were included. Mortality was higher in patients with versus without ARDS (risk ratio 2.48, 95% CI 1.86 to 3.30; p

Background Acute respiratory distress syndrome (ARDS) is heterogeneous. As an indication of the heterogeneity of ARDS, there are patients whose syndrome improves rapidly (i.e., within 24 hours), others whose hypoxemia improves gradually and still others whose severe hypoxemia persists for several days. The latter group of patients with persistent severe ARDS poses challenges to clinicians. We attempted to assess the baseline characteristics and outcomes of persistent severe ARDS and to identify which variables are useful to predict it. Methods A secondary analysis of patient-level data from the ALTA, EDEN and SAILS ARDSNet clinical trials was conducted. We defined persistent severe ARDS as a partial pressure of arterial oxygen to fraction of inspired oxygen ratio (PaO2:FiO(2)) of equal to or less than 100 mmHg on the second study day following enrollment. Regularized logistic regression with an L1 penalty [Least Absolute Shrinkage and Selection Operator (LASSO)] techniques were used to identify predictive variables of persistent severe ARDS. Results Of the 1531 individuals with ARDS alive on the second study day after enrollment, 232 (15%) had persistent severe ARDS. Of the latter, 100 (43%) individuals had mild or moderate hypoxemia at baseline. Usage of vasopressors was greater [144/232 (62%) versus 623/1299 (48%); p< 0.001] and baseline severity of illness was higher in patients with versus without persistent severe ARDS. Mortality at 60 days [95/232 (41%) versus 233/1299 (18%); p< 0.001] was higher, and ventilator-free (p< 0.001), intensive care unit-free [0 (0-14) versus 19 (7-23); p< 0.001] and non-pulmonary organ failure-free [3 (0-21) versus 20 (1-26); p

BACKGROUND. In sepsis, there may be dysregulation in programed cell death pathways, typified by apoptosis and necroptosis. Programmed cell death pathways may contribute to variability in the immune response. TRAIL is a potent inducer of apoptosis. Receptor-interacting serine/threonine protein kinase-3 (RIPK3) is integral to the execution of necroptosis. We explored whether plasma TRAIL levels were associated with in-hospital mortality, organ dysfunction, and septic shock. We also explored the relationship between TRAIL and RIPK3. METHODS. We performed an observational study of critically ill adults admitted to intensive care units at 3 academic medical centers across 2 continents, using 1 as derivation and the other 2 as validation cohorts. Levels of TRAIL were measured in the plasma of 570 subjects by E LISA. RESULTS. In all cohorts, lower (

An aircraft configuration for a deck launched intercept mission was investigated. The mission requirements for the carrier-launched and recovered aircraft included Mach 6 cruise out to a 1000 nautical mile combat radius and 20 minutes of combat followed by return to the carrier. A conical-flow waverider served as the starting point for the aircraft configuration. A hydrocarbon scramjet was integrated with the waverider body. The aft end of the waverider was faired to decrease the base area thereby reducing the transonic base drag. A numerical optimization was then completed to maximize the product of L/D (lift to drag ratio) and I sub sp (specific impulse). Variables for the optimization included the cone shock angle (used to derive the conical flow waverider) and the geometry of both the waverider body and the integrated propulsion system. The vehicle was constrained to a minimum volume of 3240 cubic feet, a maximum span of 60 feet and a fixed length of 60 feet. The integrated propulsion system was constrained to produce a minimum contraction ratio of 12.0 and assurance that the cowl shock was within an acceptable distance of the inlet shoulder of the combustor. The optimum configuration met or exceeded all constraints. L/D comparisons were made between the integrated configuration (i.e., the subject of this study), pure Mach 6 optimized waveriders and historical trends. http://archive.org/details/optimizationndpe1094539832 Lieutenant, United States Navy Approved for public release; distribution is unlimited.

Aircraft Design, Systems, and Operations Meeting, 09 August 1993 - 11 August 1993 The article of record as published may be located at https://doi.org/10.2514/6.1993-4007 The graduate program of the Department of Aeronautics and Astronautics at the Naval Postgraduate School uniquely supports a comprehensive design program in aircraft, spacecraft, missile, helicopter, and engine design. This paper is focused on four aircraft configuration designs proposed by AA 4273 Military Aircraft Design course team members. The AA 4273 course is, in turn, supported by a growing research program to enhance and further develop the methodology of aircraft design. This design effort has received considerable support from the NASA/USRA Advanced Design Program in Aeronautics. Specifically, two design solutions for a long-range,carrier based, tactical, wave-rider configured fighter/interceptor aircraft are reviewed herein, as are two solutions for a global range military transport. Both types of aircraft were developed as a graduate student team response to specific design RFPs.