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Pressure Components (pressure + component)

Distribution by Scientific Domains

Medical Sciences	75%

Selected Abstracts

Blood Pressure Components in Clinical Hypertension

JOURNAL OF CLINICAL HYPERTENSION, Issue 9 2006
Michel E. Safar MD
This review offers a critical evaluation of the remarkable progress in antihypertensive therapy since its inception. Despite the introduction of newer, more sophisticated drugs, treatment results have remained stable. Problems impeding further improvement include limited patient compliance, clinical inertia, incomplete adherence to guidelines, and dependence on brachial artery cuff pressures for diagnosis, risk assessment, and treatment response. Brachial artery systolic and pulse pressures do not reliably represent aortic or carotid artery pressures, which are better risk predictors for the heart and brain. Mean pressure, which is the same throughout the arterial tree, is directly measurable by cuff oscillometry, and might become the best single risk predictor. Available drugs have limited ability to decrease the aortic stiffness that is responsible for the elevated systolic blood pressure of aging. Therefore, to improve risk assessment and therapeutic benefit, we might include mean blood pressure and pulse pressure into blood pressure measurements, pursue efforts to measure central blood pressure, and search for new drugs to reduce arterial stiffness. [source]

Assessment of the intrinsic urethral sphincter component function in postprostatectomy urinary incontinence

NEUROUROLOGY AND URODYNAMICS, Issue 3 2002
Christian Pfister
Abstract Postprostatectomy incontinence remains a disabling condition. Sphincter injury, detrusor instability, and decreased bladder compliance have been previously reported as major factors. The aim of this study was to evaluate the urethral sphincter intrinsic component, which may provide passive continence. A urodynamic evaluation was performed in 20 patients undergoing a radical retropubic prostatectomy in the preoperative period and 3 months after surgery. Patients with disabled urinary incontinence underwent a new urodynamic evaluation 6 months later. The urethral pressure profile was measured just before, then 10, 20, and 30 minutes after the injection of 0.5 mg/kg moxisylyte chlorhydrate, an alpha adrenergic blocker. Three different pressure components were defined in urethral sphincter capacity: baseline, adrenergic, and voluntary. A postoperative intrinsic urethral sphincter pressure component was found in 17 patients and its value was under 6 cm H2O in five cases of severe incontinence. No significant difference was observed for these patients on urethral profile components 6 months later. In contrast, in cases of significant intrinsic component value, no incontinence was observed in most patients. Passive continence after radical prostatectomy should be a matter of concern and may also explain paradoxical incontinence, despite high voluntary urethral pressure obtained after reeducation. A follow-up evaluation of the intrinsic sphincter component is suggested, by using an alpha receptor blockage test during urodynamic studies in the management of patients with postprostatectomy incontinence. Neurourol. Urodynam. 21:194,197, 2002. © 2002 Wiley-Liss, Inc. [source]

A linear finite element acoustic fluid,structure model of ultrasonic angioplasty in vivo

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 7 2010
Mark P. Wylie
Abstract The delivery of high-power ultrasonic energy via small diameter wire waveguides represents a new alternative therapy for the treatment of chronic totally occluded arteries (CTOs). This type of energy manifests itself as a mechanical vibration at the distal-tip of the waveguide with amplitudes of vibration up to 60,µm and at frequencies of 20,50,kHz. Disruption of diseased tissue is reported to be a result of direct mechanical ablation, cavitation, pressure components and acoustic streaming and that ablation was only evident above the cavitation threshold. This work presents a linear finite element acoustic fluid,structure model of an ultrasonic angioplasty waveguide in vivo. The model was first verified against a reported analytical solution for an oscillating sphere. It was determined that 140 elements per wavelength (EPW) were required to predict the pressure profile generated by the wire waveguide distal-tip. Implementing this EPW count, the pressure field surrounding a range of distal-tip geometries was modelled. For validation, a model was developed with parameters based on a bench-top experiment from the literature of an ultrasonic wire waveguide in a phantom leg. This model showed good correlation with the experimental measurements. These models may aid in the further development of this technology. Copyright © 2010 John Wiley & Sons, Ltd. [source]