ABSTRACT
The effects of aorto-femoral bypass grafts on the vascular input impedance, and the ratio of pulsatile to total power were studied in eight dogs. Unilateral ileo-femoral stenosis was simulated and comparisons were made between the input impedance and power distribution in healthy and simulated disease situations. Input impedance magnitude spectra and phase were displayed graphically and it was shown that the presence of the simulated disease increases the ratio of pulsatile to total power as measured in the abdominal aorta from 7.5 to 14.8% (p less than 0.05). This suggests that the presence of the stenosis creates an impedance mismatch thus causing reflected waves to propagate proximally towards the heart. It was concluded that the way in which the heart transfers fluid power into the arterial bed was compromised by the presence of the ileo-femoral partial stenoses. It is further suggested that the system described in the paper makes it possible to quantitatively assess afterload, vascular input impedance and cardiovascular power distribution as a quasi-real time diagnostic procedure.
Subject(s)
Aorta, Abdominal/surgery , Femoral Artery/surgery , Thrombophlebitis/physiopathology , Thrombophlebitis/surgery , Vascular Resistance , Anastomosis, Surgical , Animals , Aorta, Abdominal/physiopathology , Dogs , Femoral Artery/physiopathology , Monitoring, Physiologic , Pressure , Pulsatile FlowABSTRACT
This communication presents the development of an optimal digital differentiating filter based on the Wiener theory for estimating the peak derivative of the left ventricular pressure (LVP) signal. The magnitude coherence function is used to estimate the signal and noise spectra. The peak derivative obtained by this method is found to be within 2% of the results obtained by a seven-point second-order data fit and a DFT technique.
Subject(s)
Models, Cardiovascular , Signal Processing, Computer-Assisted , Ventricular Function , Algorithms , Humans , PressureSubject(s)
Computers , Microcomputers , Myocardial Contraction , Coronary Disease/physiopathology , Hemodynamics , Humans , MathematicsABSTRACT
OBJECTIVE: To review the current status of psychiatry in selected countries of Central and Eastern Europe: Bulgaria, Croatia, Czech Republic, Hungary, Poland, Romania, Russia, Slovakia, and Slovenia. METHOD: A group of psychiatrists from the region evaluated the status of psychiatry at the end of 2004 based on data from their countries and information available on WHO homepages. RESULTS: There is a shift from traditional in-patient facilities towards out-patient and community services as evidenced by a decreasing number of hospital beds. Economic pressures affect the financing of psychiatric services, and reimbursement for novel psychotropics. Political changes were followed by updated legislation. Psychiatric training, pre-, postgraduate and continuous medical education, are gradually being transformed. Scientific output as measured by publications in peer-reviewed journals has been significantly lower than in the West. CONCLUSION: The major changes in the period of transition documented in the review pose new challenges for psychiatry.
Subject(s)
Mental Health Services/organization & administration , Psychiatry/organization & administration , Bulgaria/epidemiology , Croatia/epidemiology , Czech Republic/epidemiology , Humans , Hungary/epidemiology , Insurance, Health, Reimbursement/economics , Insurance, Health, Reimbursement/legislation & jurisprudence , Mental Health Services/economics , Mental Health Services/legislation & jurisprudence , Poland/epidemiology , Psychiatry/economics , Psychiatry/legislation & jurisprudence , Psychotropic Drugs/economics , Psychotropic Drugs/therapeutic use , Romania/epidemiology , Russia/epidemiology , Slovakia/epidemiology , Slovenia/epidemiologyABSTRACT
A new suture-holding clamp is described which simplifies single-layer colorectal anastomosis performed deep in the pelvis.
Subject(s)
Colon/surgery , Rectum/surgery , Suture Techniques/instrumentation , HumansABSTRACT
An algorithm, based on correlation techniques, is proposed for estimating the signal-to-noise ratio of very low frequency signals contaminated by white and flicker noise. Sampling techniques based on converting a single continuous signal into two time series that satisfy the requirements of cross-correlation functions are proposed. The algorithm has been tested on simulated data and the electrocardiogram transduced from ten patients.