The number of wires for sternal closure has a significant influence on sternal complications in high-risk patients

Abstract OBJECTIVES: Sternal dehiscence and mediastinitis are rare but serious complications following cardiac surgery. The aim of this study was to investigate the influence of the number of sternal wires used for chest closure on sternal complications. RESULTS: Sternal complications occurred in 2.4%, and hospital mortality with or without sternal complications were 2.8 and 2.7%, respectively (P = 0.60). Mean numbers of sternal wires were 7.8 in both patient groups with or without sternal complications (P = 0.79). Multivariate analysis revealed diabetes mellitus [odds ratio (OR) 1.54, 95% CI 1.01-2.34, P = 0.04], chronic obstructive pulmonary disease (OR 1.85, 95% CI 1.12-2.79, P = 0.01) and renal insufficiency (OR 1.70, 95% CI 1.11-2.59, P = 0.001) as significant risk factors for sternal complications. In high-risk patients, the use of less than eight wires was significantly associated with postoperative sternal complications. CONCLUSIONS: Particularly in high-risk patients, careful haemostasis should be done and eight or more wires should be used to avoid sternal complications

Multiplexed identification, quantification and genotyping of infectious agents using a semiconductor biochip

The emergence of pathogens resistant to existing antimicrobial drugs is a growing worldwide health crisis that threatens a return to the pre-antibiotic era. To decrease the overuse of antibiotics, molecular diagnostics systems are needed that can rapidly identify pathogens in a clinical sample and determine the presence of mutations that confer drug resistance at the point of care. We developed a fully integrated, miniaturized semiconductor biochip and closed-tube detection chemistry that performs multiplex nucleic acid amplification and sequence analysis. The approach had a high dynamic range of quantification of microbial load and was able to perform comprehensive mutation analysis on up to 1,000 sequences or strands simultaneously in <2 h. We detected and quantified multiple DNA and RNA respiratory viruses in clinical samples with complete concordance to a commercially available test. We also identified 54 drug-resistance-associated mutations that were present in six genes of Mycobacterium tuberculosis, all of which were confirmed by next-generation sequencing

Alternating Priority Versus FCFS Scheduling in a Two-Class Queueing System

For the single-server two-class queueing system studied in the classical text of Conway et al. (1967), we compare the mean flow times for First-Come, First-Served (FCFS) and Alternating Priority (AP) scheduling rules assuming zero setup costs for switching between classes. We show that the condition for the superiority of AP over FCFS stated in that text is incorrect, provide the correct conditions, and establish a lower bound on the difference between the mean flow times under the two rules

Comparing Functional and Cellular Layouts: A Simulation Study Based on Standardization

In the last decade, over two dozen simulation studies have focused on comparing cellular and functional layouts. The results reported by these studies vary widely, however. This remains true even when the key performance measure is flow time. These variations reflect the disparate manufacturing and operating environments, as well as differences in parts demands, set-up economies, overall loads and other factors. This work attempts to reduce the sources of variation due to different operating assumptions while retaining the variability associated with differences in part mix and demand characteristics. Instead of focusing on a single data source, this study uses a test bed of six problems extracted from the literature and ensures they share the same operational rules. The simulation results show that conversion to CMS can reduce flow times (relative to the job shop configuration) consistently across all data sets, provided the same operating rules and ranges for key parameter are used. We investigate the reduction in flow time while controlling for the key factors of set-up reduction, overall load on the system and batch size. We also assess the benefits of using transfer batches as a further factor in reducing flow time. Our overall conclusion is that set-up reductions in cells can overcome pooling losses, even under the conservative assumptions where batch size remain unchanged and the material transport times in the job shop are assumed to be negligible

Computational fluid dynamics in patients with continuous-flow left ventricular assist device support show hemodynamic alterations in the ascending aorta

Increased use of continuous-flow left ventricular assist devices for long-term mechanical support necessitates a better understanding of hemodynamic changes in the native heart and the ascending aorta. By using patient-specific computational models, correlations of potentially adverse hemodynamic conditions with the orientation of the left ventricular assist device outflow graft and their relationship with aortic insufficiency and ischemic events were investigated. Computed hemodynamic parameters, including wall shear stress, pressure in the ascending aorta, and dissipation of turbulent energy, were correlated with the orientation of the left ventricular assist device graft outflow in 5 patients (4 with the HeartMate II device [Thoratec Corp, Pleasanton, Calif] and 1 with the HeartWare Ventricular Assist Device [HeartWare Inc, Framingham, Mass]; 3 patients experienced moderate aortic insufficiency, and 2 patients experienced ischemic events). Hemodynamic conditions for aortic insufficiency and ischemic events were differentiated by linear discriminant analysis. Positive correlations between left ventricular assist device outflow graft orientation and wall shear stress, pressure, and turbulent energy dissipation in the ascending aorta were found (R(2) > 0.68). Linear discriminant analysis indicated a relationship of the velocity magnitude of retrograde flow toward the aortic root with aortic insufficiency and of the turbulent energy and wall shear stress with ischemic events. Computational fluid dynamic simulations using clinical image data indicate altered hemodynamic conditions after left ventricular assist device implantation. Consequently, the left ventricular assist device outflow graft should be placed so the jet of blood is aimed toward the lumen of the aortic arch to avoid turbulences that will increase wall shear stress and retrograde pressure of the aortic root. Further investigations are warranted to confirm these findings in a larger patient cohort

Essen-Commando:How we do it

In rare cases of extensive aortic root or mitral valve infective endocarditis (IE), severe calcification of the aortic and mitral valves, or double-valve procedures in patients with small aortic and mitral annuli, surgical reconstruction of the intervalvular fibrous body (IVFB) is required. A high mortality is generally associated with this procedure, and it is frequently avoided by surgeons due to a lack of experience. It is crucial to radically resect all tissues that are severely affected by IE to prevent recurrence in the patient. Our experience with the Commando procedure in patients with extensive double-valve IE involving the IVFB is presented in this article.</p