Modeling and simulation of right ventricular volume measurement system during right heart catheterization

Haemodynamic monitoring is necessary for the effective management of critically ill cardiac patients. Pulmonary artery catheterization has been used for monitoring the circulation, for measurement of intracardiac pressures and to estimate preload and afterload. However, pressures may not be accurate reflection of the circulation and simultaneous measurement of volumes would improve patient treatment. However, measurement of cardiac volumes especially of the right ventricle is difficult in everyday clinical practice In this work we propose the use of pulmonary artery catheter (PAC) with ultrasonic sensors built on it, to calculate the right ventricular end-diastolic (RVEDV) and end-systolic volume (RVESV). This is achieved by using the Ultrasonic (US) beam, to measure the distances between the transducers on the catheter and the RV walls. These distances, will be used as an input to a Volume calculating algorithm, which finally provides the RVEDV and RVESV, using a Neural Network (NN). For that reason, we have used cardiac Magnetic Resonance Imaging (MRI) and have modeled the catheter and the US transducers, to get as input the distances to the surface of the cavity. With these distances, and the known cardiac volumes (calculated using MR images) we trained and validated a NN for volume calculation. The results show that the algorithm accurately calculates the RVEDV. For the RVESV, greater deviations are observed between values calculated with our algorithm and cardiac MRI. © Springer Science+Business Media, LLC 2010

The impact of Greek publications on the international literature by scientific category

OBJECTIVE: To investigate the penetration of Greek publications in the international literature by scientific category. METHOD: We used the publications database of the Institute for Scientific Information® (ISI), the search engine that is available through its web pages as well as a re-tabulation of the 120 scientific categories of ISI into 50 broader categories. We counted the publications that appeared during the decade 1994-2003 in the 30 journals of each category with the highest impact factor (IF) and, among them, the proportion of the Greek publications. A more valid comparison between scientific categories was attempted using a new index, the index of Greek contribution (IGC), that takes into account the relative number (‰) of Greek publications among the sum of publications of each category in the 30 most prominent journals as well as the journals' IFs. RESULTS: The 20528 Greek publications represent the 4.73‰ of all the 4,340,793 publications appearing in the above ISI journals during the decade 1994-2003. The distribution of Greek publications by scientific category indicates that more than 55% of the publications originated from medical specialties. Among them, Oncology and Heart Diseases were the specialties with the highest international penetration. CONCLUSIONS: The presence of Greek scientific publications in the international literature is noticeable, if the population of the country is taken in account, but further improvement is necessary. Among all publication in the international scientific literature, the ones with medical content represent more than 55% of the total or the quality adjusted total

Injuries in public and private playgrounds: the relative contribution of structural, equipment and human factors

The aim of this case-control Study was to identify and quantify risk factors of injuries in playgrounds, where children spend an increasing amount of time in developed Countries. The study took place in Greater Athens during 1999. A continuous Emergency Departments Injury Surveillance System (EDISS) of hospitals that cover about 30% of the children’s time at risk in Greater Athens identified 777 injuries in public and private playgrounds out of a total of 17 497 injuries. Public playgrounds differ from private ones, because the former generally have more equipment. usually of greater height, with less resilient surfaces. and supervision relies mainly on parents or guardians. Patterns of type of playground use were assessed in a sample of 294 children from the same study base who served as a control group in a hierarchical case-control design. The annual incidence of playground injuries in Greater Athens vas about 7 in 1000 among boys and 4 in 1000 among girls, with a 2.2 times higher risk for an injury in public than in private playgrounds (95% confidence interval 1.61-3.07). Children in public vs private playgrounds had a statistically significant eight times higher odds for concussion and six times higher for open wounds, whereas the odds for long bone fractures were four and for other fractures two; swings, slides and seesaws were the types of equipment most frequently associated with injuries. It was further shown that supervision of children was suboptimal (<60%) in both public and private playgrounds. and children in private playgrounds sustained an unduly high frequency of sprain/ dislocation injuries (odds ratio 1.75) because they were encouraged to play bare-footed. Conclusion: Close to 50%, of playground injuries could be prevented by structural and equipment changes. while further reduction could be accomplished through simple measures including closer supervision and encouraging children to wear proper shoes and use, whenever necessary