Background Acute Respiratory Distress Syndrome (ARDS) is a devastating condition with an estimated mortality exceeding 30%. There are data suggesting risk factors for ARDS development in high-risk populations, but few data are available in lower incidence populations. Using risk-matched analysis and a combination of clinical and research datasets, we determined the incidence and risk factors for the development of ARDS in this general surgical population. Methods We conducted a review of common adult surgical procedures completed between January 1, 2005 and July 1, 2009 using an anesthesia information system. This dataset was merged with an ARDS registry and an institutional death registry. Preoperative variables were subjected to multivariate analysis. Matching and multivariate regression was used to determine intraoperative factors associated ARDS development. Results 50,367 separate patient admissions were identified, 93 (0.2%) of these patients developed ARDS. Preoperative risk factors for ARDS development included American Society of Anesthesiologist status 3-5(odds ratio (OR) 18.96), emergent surgery (OR 9.34), renal failure (OR 2.19), chronic obstructive pulmonary disease (OR 2.16), number of anesthetics during the admission (OR 1.37), and male sex (OR 1.65). After matching, intraoperative risk factors included drive pressure (OR 1.17), fraction inspired oxygen (OR 1.02), crystalloid administration in liters (1.43) and erythrocyte transfusion (OR 5.36). Conclusion ARDS is a rare condition postoperatively in the general surgical population and is exceptionally uncommon in low American Society of Anesthesiologists status patients undergoing scheduled surgery. Analysis after matching suggests ARDS development is associated with median drive pressure, FiO2, crystalloid volume, and transfusion.

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The use of extracorporeal membrane oxygenation (ECMO) has grown rapidly in recent years. We sought to describe the rate of ECMO use in the United States, regional variation in ECMO use, the hospitals performing ECMO, and the primary payers for ECMO patients. Detailed data were obtained using the Healthcare Cost and Utilization Project (HCUPnet) summaries of State Inpatient Databases from 34 participating states for the years 2011–2014. The ECMO rates over time were modeled, overall and within subcategories of age group, bed size, hospital ownership, teaching status, and payer type. During the study period, the overall rate of ECMO use increased from 1.06 (1.01, 1.12) to 1.77 (1.72, 1.82) cases per 100,000 persons per year (p = 0.005). The rate of ECMO use varied significantly by region. Most ECMO patients are cared for at large hospitals, and at private, not-for-profit hospitals with teaching designation. The most common payer was private insurance; a minority of patient were uninsured. The use of ECMO increased significantly during the study period, but regional variation in the rate of ECMO use suggests that this technology is not being uniformly applied. Further research is warranted to determine why differences in ECMO use persist and what impact they have on patient outcomes.

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Humanized mice are a state-of-the-art tool used to study several diseases, helping to close the gap between mice and human immunology. This review focuses on the potential obstacles in the analysis of immune system performance between humans and humanized mice in the context of severe acute inflammation as seen in sepsis or other critical care illnesses. The extent to which the reconstituted human immune system in mice adequately compares to the performance of the human immune system in human hosts is still an evolving question. Although certain viral and protozoan infections can be replicated in humanized mice, whether a highly complex and dynamic systemic inflammation like sepsis can be accurately represented by current humanized mouse models in a clinically translatable manner is unclear. Humanized mice are xenotransplant animals in the most general terms. Several organs (e.g., bone marrow mesenchymal cells, endothelium) cannot interact with the grafted human leukocytes effectively due to species specificity. Also the interaction between mice gut flora and the human immune system may be paradoxical. Often, grafting is performed utilizing an identical batch of stem cells in highly inbred animals which fails to account for human heterogeneity. Limiting factors include the substantial cost and restricting supply of animals. Finally, humanized mice offer an opportunity to gain knowledge of human-like conditions, requiring careful data interpretation just as in nonhumanized animals.