11 research outputs found
Determination of thermophysical characteristics of solid materials by electrical modelling of the solutions to the inverse problems in nonsteady heat conduction
The solution of the inverse problem of nonsteady heat conduction is discussed, based on finding the coefficient of the heat conduction and the coefficient of specific volumetric heat capacity. These findings are included in the equation used for the electrical model of this phenomenon
Distal Versus Conventional Radial Access for Coronary Angiography and Intervention: The DISCO RADIAL Trial.
BACKGROUND: Currently, transradial access (TRA) is the recommended access for coronary procedures because of increased safety, with radial artery occlusion (RAO) being its most frequent complication, which will increasingly affect patients undergoing multiple procedures during their lifetimes. Recently, distal radial access (DRA) has emerged as a promising alternative access to minimize RAO risk. A large-scale, international, randomized trial comparing RAO with TRA and DRA is lacking. OBJECTIVES: The aim of this study was to assess the superiority of DRA compared with conventional TRA with respect to forearm RAO. METHODS: DISCO RADIAL (Distal vs Conventional Radial Access) was an international, multicenter, randomized controlled trial in which patients with indications for percutaneous coronary procedure using a 6-F Slender sheath were randomized to DRA or TRA with systematic implementation of best practices to reduce RAO. The primary endpoint was the incidence of forearm RAO assessed by vascular ultrasound at discharge. Secondary endpoints include crossover, hemostasis time, and access site-related complications. RESULTS: Overall, 657 patients underwent TRA, and 650 patients underwent DRA. Forearm RAO did not differ between groups (0.91% vs 0.31%; P = 0.29). Patent hemostasis was achieved in 94.4% of TRA patients. Crossover rates were higher with DRA (3.5% vs 7.4%; P = 0.002), and median hemostasis time was shorter (180 vs 153 minutes; P < 0.001). Radial artery spasm occurred more with DRA (2.7% vs 5.4%; P = 0.015). Overall bleeding events and vascular complications did not differ between groups. CONCLUSIONS: With the implementation of a rigorous hemostasis protocol, DRA and TRA have equally low RAO rates. DRA is associated with a higher crossover rate but a shorter hemostasis time
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Pulse rate variability in cardiovascular health: a review on its applications and relationship with heart rate variability
Heart rate variability has been largely used for the assessment of cardiac autonomic activity, due to the direct relationship between cardiac rhythm and the activity of the sympathetic and parasympathetic nervous system. In recent years, another technique, pulse rate variability, has been used for assessing heart rate variability information from pulse wave signals, especially from photoplethysmography, a non-invasive, non-intrusive, optical technique that measures the blood volume in tissue. The relationship, however, between pulse rate variability and heart rate variability is not entirely understood, and the effects of cardiovascular changes in pulse rate variability have not been thoroughly elucidated. In this review, a comprehensive summary of the applications in which pulse rate variability has been used, with a special focus on cardiovascular health, and of the studies that have compared heart rate variability and pulse rate variability is presented. It was found that the relationship between heart rate variability and pulse rate variability is not entirely understood yet, and that pulse rate variability might be influenced not only due to technical aspects but also by physiological factors that might affect the measurements obtained from pulse-to-pulse time series extracted from pulse waves. Hence, pulse rate variability must not be considered as a valid surrogate of heart rate variability in all scenarios, and care must be taken when using pulse rate variability instead of heart rate variability. Specifically, the way pulse rate variability is affected by cardiovascular changes does not necessarily reflect the same information as heart rate variability, and might contain further valuable information. More research regarding the relationship between cardiovascular changes and pulse rate variability should be performed to evaluate if pulse rate variability might be useful for the assessment of not only cardiac autonomic activity but also for the analysis of mechanical and vascular autonomic responses to these changes