Background The influence of prior coronary artery bypass surgery (CABG) versus medical therapy for reducing the risk of postoperative cardiac complications after noncardiac surgery continues to be ...debated. To further clarify this controversy we studied 24 959 participants in the Coronary Artery Surgery Study (CASS) database with suspected coronary disease by identifying those who required noncardiac surgery during more than 10 years of follow-up. Methods and Results CASS registry enrollees were either treated with CABG or medical therapy after initial entry. During follow-up, patients who required noncardiac operations were evaluated for hospital death or out-of-hospital death within 30 days of noncardiac surgery and nonfatal postoperative myocardial infarction (MI). At a mean follow-up of 4.1 years, 3368 patients underwent noncardiac surgery, with abdominal (36%), urologic (21%), orthopedic (15%), and vascular being most common. Abdominal, vascular, thoracic, and head and neck surgery each had a combined MI/death rate among patients with nonrevascularized coronary disease >4%. Among 1961 patients undergoing higher-risk surgery, prior CABG was associated with fewer postoperative deaths (1.7% versus 3.3%, P =.03) and MIs (0.8% versus 2.7%, P =.002) compared with medically managed coronary disease. Contrariwise, 1297 patients undergoing urologic, orthopedic, breast, and skin operations had mortality of <1% regardless of prior coronary treatment. Prior CABG was most protective in patients with advanced angina and/or multivessel coronary artery disease. Conclusions In patients with known coronary artery disease, noncardiac surgeries involving the thorax, abdomen, vasculature, and head and neck are associated with the highest cardiac risk, which is reduced among patients with prior CABG.
AbstractAlthough influenza has been associated with chronic obstructive pulmonary disease (COPD) exacerbations, it is not clear the extent to which this association affects healthcare use in the ...United States. The first goal of this project was to determine to what extent the incidence of COPD hospitalizations is associated with seasonal influenza. Second, as a natural experiment, we used influenza activity to help predict COPD admissions during the 2009 H1N1 influenza pandemic. To do this, we identified all hospitalizations between 1998 and 2010 in the Nationwide Inpatient Sample from the Healthcare Cost and Utilization Project (HCUP) during which a primary diagnosis of COPD was recorded. Separately, we identified all hospitalizations during which a diagnosis of influenza was recorded. We formulated time series regression models to investigate the association of monthly COPD admissions with influenza incidence. Finally, we applied these models, fit using 1998-2008 data, to forecast monthly COPD admissions during the 2009 pandemic. Based on time series regression models, a strong, significant association exists between concurrent influenza activity and incidence of COPD hospitalizations (p-value < 0.0001). The association is especially strong among older patients requiring mechanical ventilation. Use of influenza data to predict COPD admissions during the 2009 H1N1 pandemic reduced the mean-squared prediction error by 29.9%. We conclude that influenza activity is significantly associated with COPD hospitalizations in the United States and influenza activity can be exploited to more accurately forecast COPD admissions. Our results suggest that improvements in influenza surveillance, prevention, and treatment may decrease hospitalizations of patients diagnosed with COPD.
Velocimetry of ceramic particles ejected via cathode spot eruption on the surface of a biased electrode in the presence of a low-density plasma has been carried out. Witness plate measurements ...indicated the rate of powder removal to be greater than 3.0 mg/s. An expanded laser beam and fast frame-rate camera were used to perform laser-illuminated particle imaging velocimetry measurements. The velocity distribution for 45- μm-diameter ceramic particles was found to range between 0.2 and 1.5 m/s in the plane of view as they are ejected from the electrode surface. Nonuniform powder ejection in the horizontal plane is shown to be related to the presence of an applied magnetic field.
Cathode spots have been observed to form on an electrode surface covered with dielectric powder when biased at large negative voltages in the presence of a background plasma. The ignition of cathode ...spots leads to the ejection of the powder particles, which subsequently form dust streams. Particle imaging velocimetry (PIV) techniques are used to track the ejected particles and obtain the distribution of particle ejection velocities.
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