Milan V. Petrovic

European Maxillofacial Trauma (EURMAT) project: A multicentre and prospective study

The purpose of this study was to analyse the demographics, causes and characteristics of maxillofacial fractures managed at several European departments of oral and maxillofacial surgery over one year. The following data were recorded: gender, age, aetiology, site of facial fractures, facial injury severity score, timing of intervention, length of hospital stay. Data for a total of 3396 patients (2655 males and 741 females) with 4155 fractures were recorded. The mean age differed from country to country, ranging between 29.9 and 43.9 years. Overall, the most frequent cause of injury was assault, which accounted for the injuries of 1309 patients; assaults and falls alternated as the most important aetiological factor in the various centres. The most frequently observed fracture involved the mandible with 1743 fractures, followed by orbital-zygomatic-maxillary (OZM) fractures. Condylar fractures were the most commonly observed mandibular fracture. The results of the EURMAT collaboration confirm the changing trend in maxillofacial trauma epidemiology in Europe, with trauma cases caused by assaults and falls now outnumbering those due to road traffic accidents. The progressive ageing of the European population, in addition to strict road and work legislation may have been responsible for this change. Men are still the most frequent victims of maxillofacial injuries.

Acute insulin resistance in ST-segment elevation myocardial infarction in non-diabetic patients is associated with incomplete myocardial reperfusion and impaired coronary microcirculatory function

BackgroundInsulin resistance (IR) assessed by the Homeostatic Model Assessment (HOMA) index in the acute phase of myocardial infarction in non-diabetic patients was recently established as an independent predictor of intrahospital mortality. In this study we postulated that acute IR is a dynamic phenomenon associated with the development of myocardial and microvascular injury and larger final infarct size in patients with ST-segment elevation myocardial infarction (STEMI) treated by primary percutaneous coronary intervention (pPCI).MethodsIn 104 consecutive patients with the first anterior STEMI without diabetes, the HOMA index was determined on the 2nd and 7th day after pPCI. Worst-lead residual ST-segment elevation (ST-E) on postprocedural ECG, coronary flow reserve (CFR) determined by transthoracic Doppler echocardiography on the 2nd day after pPCI and fixed perfusion defect on single-photon emission computed tomography myocardial perfusion imaging (SPECT-MPI) determined six weeks after pPCI were analyzed according to HOMA indices.ResultsIR was present in 55 % and 58 % of patients on day 2 and day 7, respectively. Incomplete post-procedural ST-E resolution was more frequent in patients with IR compared to patients without IR, both on day 2 (pu2009=u20090.001) and day 7 (pu2009<u20090.001). The HOMA index on day 7 correlated with SPECT-MPI perfusion defect (ru2009=u20090.331), whereas both HOMA indices correlated well with CFR (ru2009=u2009-0.331 to -0.386) (pu2009<u20090.01 for all). In multivariable backward logistic regression analysis adjusted for significant univariate predictors and potential confounding variables, IR on day 2 was an independent predictor of residual ST-E ≥ 2xa0mm (OR 11.70, 95% CI 2.46-55.51, pu2009=u20090.002) and CFRu2009<u20092 (ORu2009=u20095.98, 95% CI 1.88-19.03, pu2009=u20090.002), whereas IR on day 7 was an independent predictor of SPECT-MPI perfusion defect > 20% (OR 11.37, 95% CI 1.34-96.21, pu2009=u20090.026).ConclusionIR assessed by the HOMA index during the acute phase of the first anterior STEMI in patients without diabetes treated by pPCI is independently associated with poorer myocardial reperfusion, impaired coronary microcirculatory function and potentially with larger final infarct size.

European Maxillofacial Trauma (EURMAT) in children: A multicenter and prospective study

OBJECTIVEnThe aim of this study is to present and discuss the results of a European multicentre prospective study about pediatric maxillofacial trauma epidemiology during a year.nnnSTUDY DESIGNnThe following data were recorded: gender, age, etiology, site of fracture, date of injury. Of the 3396 patients with maxillofacial fractures admitted within the study period, 114 (3.3%) were children aged 15 years and younger, with a male/female ratio of 2.6:1. Mean age was 10.9 years. Most patients (63%) were aged 11-15 years.nnnRESULTSnThe most frequent cause of injury was fall (36 patients). Sport injuries and assaults were almost limited to the oldest group, whereas falls were more uniformly distributed in the 3 groups. The most frequently observed fracture involved the mandible with 47 fractures. In particular, 18 condylar fractures were recorded, followed by 12 body fractures.nnnCONCLUSIONSnFalls can be acknowledged as the most important cause of facial trauma during the first years of life. The high incidence of sport accidents after 10 years may be a reason to increase the use of mouthguards and other protective equipment. Finally, the mandible (and in particular the condyle) was confirmed as the most frequent fracture site.

Assault-related maxillofacial injuries: the results from the European Maxillofacial Trauma (EURMAT) multicenter and prospective collaboration

OBJECTIVEnThe aim of this study is to present and discuss the demographic characteristics and patterns of assault-related maxillofacial fractures as reported by a European multicenter prospective study.nnnSTUDY DESIGNnDemographic and injury data were recorded for each patient who was a victim of an assault.nnnRESULTSnAssaults represented the most frequent etiology of maxillofacial trauma with an overall rate of 39% and the values ranging between 60.8% (Kiev, Ukraine) and 15.4% (Bergen, Norway). The most frequent mechanisms of assault-related maxillofacial fractures were fists in 730 cases, followed by kicks and fists. The most frequently observed fracture involved the mandible (814 fractures), followed by orbito-zygomatic-maxillary complex fractures and orbital fractures.nnnCONCLUSIONSnOur data confirmed the strong possibility that patients with maxillofacial fractures may be victims of physical aggression. The crucial role of alcohol in assault-related fractures was also confirmed by our study.

Time-dependent changes of plasma adiponectin concentration in relation to coronary microcirculatory function in patients with acute myocardial infarction treated by primary percutaneous coronary intervention

BACKGROUND AND PURPOSEnTo analyze plasma adiponectin kinetics in patients with ST-segment elevation myocardial infarction (STEMI) treated by primary percutaneous coronary intervention (pPCI) and its association with coronary flow reserve (CFR), an index of coronary microcirculatory function.nnnMETHODSnA total of 96 consecutive patients with the first anterior STEMI treated by pPCI without heart failure were included. CFR was assessed on the 7th day after pPCI. Plasma adiponectin was measured on admission before pPCI, and on the 2nd and 7th day after pPCI.nnnRESULTSnAdiponectin concentration was the highest on admission, declined to the lowest level on the 2nd day, and rose on the 7th day remaining below admission values. Impaired coronary microcirculatory function (CFR<2) was observed in 41% of the patients. Adiponectin concentrations significantly positively correlated with CFR, and the strongest correlation was with the 2nd day adiponectin (r=0.489, p<0.001). In multivariate models, adiponectin concentrations were independent predictors of impaired CFR [on admission: odds ratio (OR) 0.175, confidence interval (CI): 0.047-0.654, p=0.010; 2nd day: OR 0.146, 95% CI: 0.044-0.485, p=0.002; 7th day: OR 0.198, CI: 0.064-0.611, p=0.005]. The best power to predict impaired CFR was the 2nd day adiponectin. Delta values of adiponectin (differences between adiponectin concentrations) did not correlate with CFR.nnnCONCLUSIONSnIn patients with the first anterior STEMI treated by pPCI plasma adiponectin concentrations before and after pPCI are strongly associated with CFR. Our results support the hypothesis that low adiponectin, especially during the early post-pPCI period, carries the risk for impaired coronary microcirculatory function in STEMI patients.

Optimization of multistage turbines using a through-flow code

Abstract Fast and accurate flow calculation and performance prediction of multistage axial flow turbines at design and off-design conditions were performed using a compressible steady state inviscid through-flow code with high fidelity loss and mixing models. The code is based on a stream function model and a finite element solution procedure. A new design system has been developed which optimizes hub and shroud geometry and inlet and exit flow field parameters for each blade row of a multistage axial flow turbine. Optimization was performed using a hybrid constrained optimization code that switches among the modules automatically in order to avoid local minima and to accelerate design convergence rate. By automatically varying a relatively small number of geometric variables per turbine stage it is possible to find an optimal radial distribution of flow parameters at the inlet and outlet of every blade row. Thus, an optimized meridional flow path can be found that is defined by the optimized shape of the hub and shroud while keeping blade shapes intact. The multistage design optimization system has been demonstrated using an actual two-stage axial gas turbine as an example. The comparison of computed performance of an already very high efficiency initial design and its optimized design demonstrates more than 1 per cent improvement in the turbine efficiency at design and significant off-design conditions. The entire design optimization process is feasible on a typical single-processor computer workstation or a personal computer.

Secondary Flows, Endwall Effects and Stall Detection in Axial Compressor Design

This paper describes a methodology and a fully tested and calibrated mathematical model for the treatment of endwall effects in axial compressor aerodynamic calculations. Additional losses and deviations caused by the clearance and secondary flows are analyzed. These effects are coupled with endwall boundary layer losses (EWBL) and blockage development. Stall/surge detection is included, and mutual interaction of different loss mechanisms is considered. Individual mathematical correlations for different effects have been created or adopted from earlier papers with the aim of forming one integral model that is completely described in this paper. Separate mathematical correlations and calibration measures are discussed in detail in the first part of the paper. The developed overall model is suitable for application in two-dimensional (2D) or mean-line compressor flow calculations. During the development, it was tested, calibrated, and validated using throughflow calculations comparing numerical results with experimental data for a large number of test cases. These test cases include compressors with very different configurations and operating ranges. The data on the compressors were taken from the open literature or obtained from industrial partners.

Off-Design Flow Analysis and Performance Prediction of Axial Turbines

Through-flow methods for calculations in axial flow turbines are limited by two facts: they cannot handle local flow reversal, and loss prediction at off-design operating conditions is not sufficiently accurate. An attempt to overcome these limitations is presented in this paper. The developed calculation method is based on the through-flow theory and the finite element solution procedure, but it also includes extensions and improvements. Consequently, the method may be used to predict the flow field and the turbine performance at the design load as well as for wide range of part loads. The code is able to calculate flow in axial turbines at subsonic and transonic conditions. The reliability of the method is verified by calculations for several gas and steam turbines. Results of flow calculation and performance prediction of 4-stage experimental air turbine and LP steam turbine are also presented herein. Low load operation with flow reversal in the hub region behind the last rotor blade row and loads, at which part of blading operates with power consumption, are especially analyzed. All numerical results are compared to the results of extensive experimental investigations. The correspondence, even for low loads, is very good.Copyright

Fully Coupled Through-Flow Method for Industrial Gas Turbine Analysis

A fully coupled method for calculation of the entire flow in single- and twin-shaft industrial gas turbines is described. It is based on individual through-flow methods for axial compressors and air-cooled gas turbines developed by the authors that are coupled using simple combustion and cooling flow models connecting compressor and turbine flow paths. The through-flow computation for the analysis of cooled axial multistage turbines is fed by air from the compressor bleeds, which are part of the through-flow model of the compressor. The through-flow methods are based on a stream function approach and a finite element solution procedure. They include high-fidelity loss and deviation models with improved correlations. Advanced radial mixing and endwall boundary layer models are applied to simulate 3D flow effects. For air-cooled turbine analysis, various types of cooling air injection were adopted: film cooling, trailing edge injection and disc/endwall coolant flow. Compressor and turbine flow path computations were extensively validated individually and previously published by the authors.The coupled method was applied to operation analysis and performance prediction of a newly developed industrial gas turbine in single- and twin-shaft configurations. In the latter case, the matching point of the compressor and high-pressure turbine has to be determined iteratively as a function of the compressor speed line, firing temperature, cooling and bleed-off characteristics, which may be important for strong part-load behavior. This process is explained in the paper.Predicted gas turbine operation points are compared with experimental test data. It is demonstrated that the new method presented is an essential tool for overall gas turbine design and matching of the gas turbine components based on test rig experience. In addition, it is useful for diagnosis and supports the root-cause analysis of misbehaving field engines.Copyright

Coronary flow of the infarct artery assessed by transthoracic Doppler after primary percutaneous coronary intervention predicts final infarct size

Coronary microcirculatory function after primary percutaneous coronary intervention (pPCI) in patients with acute myocardial infarction is important determinant of infarct size (IS). Our aim was to investigate the utility of coronary flow reserve (CFR) and diastolic deceleration time (DDT) of the infarct artery (IRA) assessed by transthoracic Doppler echocardiography after pPCI for final IS prediction. In 59 patients, on the 2nd day after pPCI for acute anterior myocardial infarction, transthoracic Doppler analysis of IRA blood flow was done including measurements of CFR, baseline DDT and DDT during adenosine infusion (DDT adeno). Killip class, myocardial blush grade, resolution of ST segment elevation, peak creatine kinase-myocardial band and conventional echocardiographic parameters were determined. Single-photon emission computed tomography myocardial perfusion imaging was done 6xa0weeks later to define final IS (percentage of myocardium with fixed perfusion abnormality). IS significantly correlated with CFR (rxa0=xa0−0.686, pxa0<xa00.01), DDT (rxa0=xa0−0.727, pxa0<xa00.01), and DDT adeno (rxa0=xa0−0.780, pxa0<xa00.01). CFR and DDT adeno in multivariate analysis remained independent IS predictors after adjustment for other covariates and offered incremental prognostic value in models based on conventional clinical, angiographic, electrocardiographic and enzymatic variables. In predicting large infarction (ISxa0>xa020xa0%), the best cut-off for CFR was <1.73 (sensitivity 65xa0%, specificity 96xa0%) and for DDT adeno ≤720xa0ms (sensitivity 81xa0%, specificity 96xa0%). CFR and DDT during adenosine are independent and powerful early predictors of final IS offering incremental prognostic information over conventional parameters of myocardial and microvascular damage and tissue reperfusion.