Search results for "HEMODYNAMICS"
showing 10 items of 511 documents
Evaluation of the pulse wave arrival time as a marker for blood pressure changes in critically ill infants and children
1995
Objective. Pulse arrival time (PAT), which is the interval between the R wave of the electrocardiogram (ECG) and the arrival of the pulse wave peripherally, has been reported to be suitable for use as an indirect measure of blood pressure change. The purpose of this study was to evaluate, in critically ill infants and children, the degree to which 1/PAT covaries with systolic, diastolic, and mean blood pressure, as well as heart rate.Methods. A laboratory device was used to calculate PAT in real time from the ECG and the plethysmographic curve of pulse oximetry used for routine monitoring. Calculated PAT and corresponding blood pressures and heart rate were stored on hard disk. A total of 1…
Wall motion characteristic of the right pulmonary artery in the suprasternal echocardiogram
1980
This study describes the motion pattern of the right pulmonary artery (RPA) as it can be assessed from the suprasternal echocardiogram. The motion characteristic of the RPA is dependent on hemodynamic factors within the lumen of the RPA and those within the left atrium and the aortic arch. During atrial contraction the superior wall of the left atrium separates from the inferior wall of the RPA (IWRPA) and produces an "a" dip in the wall motion of the IWRPA. During isovolumic contraction the RPA is shifted upward (IC point). The incisura in the pulmonary artery pressure curve reflecting pulmonic valve closure can be seen by a sudden decrease in the diameter of the RPA (PC point). In conditi…
Microvascular skin blood flow following the ingestion of 75 g glucose in healthy individuals.
2009
It is expected that microvascular blood flow might be affected by blood glucose, blood insulin and C-peptide levels. In our investigation skin microvascular blood flow (LDF) was measured using laser doppler fluxometry at skin temperatures of 37 degrees C and 44 degrees C during a 75 g oral glucose load (OGT) or water in ten healthy volunteers (6 male, 4 female, age: 28.1+/-4.0) who had fasted overnight. The transcutaneous oxygen tension (tcPO2) was measured using a transcutaneous oxygen electrode at a temperature of 44 degrees C. The microvascular response to acetylcholine was investigated before the start of the ingestion period and after 30 minutes. In addition, the capillary blood cell v…
RCBF-quantification with 99mTc-HMPAO-SPECT: theory and first results.
1989
The activity concentrations of 99mTc-HMPAO in brain after intravenous injection were evaluated in 25 patients using SPECT. With additional first pass studies of heart and brain with the short lived isotope 195mAu, the cardiac output and the mean cerebral transit times of the patients were measured a short time before the HMPAO injection. The time dependence of 99mTc-HMPAO activity in the brain was registered during the first 5 min after injection over both hemispheres. Using a simplified three compartment model it was possible to calculate the mean retention fraction of HMPAO in brain from the time activity curves. It could be shown that the regional cerebral blood flow in ml/min per 100 g …
Resistive index of ophthalmic artery as an imaging biomarker of hypertension-related vascular and kidney damage
2021
Aim: Resistive index of ophthalmic artery (RI-OA) is associated with atherosclerotic diseases. The aim of this study was to evaluate the association of RI-OA and hypertension-related vascular and kidney damage. Materials and methods: Two-hundred and eighty hypertensive patients underwent evaluation of RI-OA, carotid atherosclerosis and level of 24 h albuminuria. Results: Albuminuria and carotid atherosclerosis were positively associated with RI-OA independently of other cardiovascular risk factors. Receiver-operating characteristic curve analysis allowed us to calculate a cut-off value of RI-OA >0.625, which would be suspicious about the existence of atherosclerotic disease. Conclusion:…
Gadoxetic acid-enhanced MRI of transient hepatic enhancement differences: Another cause of hypointense observation on hepatobiliary phase
2018
Purpose: To retrospectively determine the frequency, natural history and factors associated with the presence of transient hepatic enhancement difference showing hypointensity on hepatobiliary phase images of gadoxetic acid-enhanced MRI. Materials and methods: Gadoxetic acid-enhanced MRI of 125 patients (91 men; 34 women) with transient hepatic enhancement difference were retrospectively reviewed. Three readers qualitatively and quantitatively evaluated MR imaging features and evolution at follow up. The Chi-square test, Fisher's exact test and Kruskall-Wallis rank test were used for statistical analysis. Results: Transient hepatic enhancement difference were hypointense on hepatobiliary ph…
The Adverse Events and Hemodynamic Effects of Adenosine-Based Cardiac MRI
2011
OBJECTIVE We wanted to prospectively assess the adverse events and hemodynamic effects associated with an intravenous adenosine infusion in patients with suspected or known coronary artery disease and who were undergoing cardiac MRI. MATERIALS AND METHODS One hundred and sixty-eight patients (64 ± 9 years) received adenosine (140 µg/kg/min) during cardiac MRI. Before and during the administration, the heart rate, systemic blood pressure, and oxygen saturation were monitored using a MRI-compatible system. We documented any signs and symptoms of potential adverse events. RESULTS In total, 47 out of 168 patients (28%) experienced adverse effects, which were mostly mild or moderate. In 13 patie…
Chronic Thromboembolic Pulmonary Hypertension: Pre- and Postoperative Assessment with Breath-hold MR Imaging Techniques
2004
To evaluate the potential of breath-hold magnetic resonance (MR) imaging techniques in morphologic and functional assessment of patients with chronic thromboembolic pulmonary hypertension (CTEPH) before and after surgery.Thirty-four patients with CTEPH were examined before and after pulmonary thromboendarterectomy (PTE). For morphologic assessment, contrast material-enhanced MR angiography was used; for assessment of hemodynamics, velocity-encoded gradient-echo sequences and cine gradient-echo sequences along the short axis of the heart were performed. Contrast-enhanced MR angiography was compared with selective digital subtraction angiography (DSA) for depiction of central thromboembolic m…
Magnetically labeled water perfusion imaging of the uterine arteries and of normal and malignant cervical tissue: initial experiences.
1998
Purpose: The aim of this pilot study was to evaluate a magnetically labeled water perfusion imaging technique as a non-contrast-enhanced approach to demonstrate the uterine artery, its branches, and to assess the cervical uterine blood flow in healthy volunteers and in patients with advanced uterine cervical carcinoma (FIGO IIB-IVA). Methods and Materials: Seven healthy volunteers (mean age, 29 years) and twenty-two patients (mean age, 52 years) with advanced cancer of the uterine cervix (FIGO IIB-IVA) were prospectively examined by magnetically labeled water perfusion imaging at different inversion delay times (300–900 ms). The magnetic resonance imaging (MRI) findings of all patients were…
Effect of aneurysm on the mechanical dissection properties of the human ascending thoracic aorta
2012
Objectives: The acute dissection of an ascending thoracic aortic aneurysm (ATAA) represents a devastating separation of elastic layers occurring when the hemodynamic loads on the diseased wall exceed the adhesive strength between layers. At present, the mechanics underlying aortic dissection are largely unclear, and the biomechanical delamination properties of the aneurysmal aorta are not defined. Individuals with bicuspid aortic valve (BAV) are particularly predisposed to ascending aortic aneurysm formation, with a marked risk of aortic dissection. The purpose of this study was to evaluate and compare the dissection properties of nonaneurysmal and aneurysmal human ascending thoracic aorta …