Search results for " blood flow"
showing 10 items of 305 documents
Effect of chest compressions only during experimental basic life support on alveolar collapse and recruitment
2007
Summary Aim The importance of ventilatory support during cardiac arrest and basic life support is controversial. This experimental study used dynamic computed tomography (CT) to assess the effects of chest compressions only during cardiopulmonary resuscitation (CCO-CPR) on alveolar recruitment and haemodynamic parameters in porcine model of ventricular fibrillation. Materials and methods Twelve anaesthetized pigs (26±1kg) were randomly assigned to one of the following groups: (1) intermittent positive pressure ventilation (IPPV) both during basic life support and advanced cardiac life support, or (2) CCO during basic life support and IPPV during advanced cardiac life support. Measurements w…
Echocardiographic assessment of coronary microvascular dysfunction: Basic concepts, technical aspects, and clinical settings
2021
Abstract Coronary flow reserve is the capacity of the coronary circulation to augment the blood flow in response an increase in myocardial metabolic demands and has a powerful prognostic significance in different clinical situations. It might assess with invasive and noninvasive technique. Transthoracic echocardiography Doppler is an emerging diagnostic technique, noninvasive, highly feasible, safe for patient and physician, without radiation, and able to detect macrovascular and microvascular anomalies in the coronary circulation. This review aims to describe the benefit and limits of echocardiographic assessment of coronary flow reserve.
Endothelial function testing and cardiovascular disease: focus on peripheral arterial tonometry
2014
During recent decades, a number of methods have been developed to assess endothelial function, contributing to a better understanding of the pathophysiology of cardiovascular disease. Recently, the advent of noninvasive, reproducible techniques for assessment of endothelial function has opened novel possibilities of application in the clinical setting. Peripheral arterial tonometry is a relatively novel, user-friendly technique measuring finger pulse volume amplitude changes induced by reactive hyperemia following 5 minutes of ischemia in the upper limb. Current evidence indicates that this technique has the potential to significantly impact the field of cardiovascular research and preventi…
The Effects of Renal Denervation on Renal Hemodynamics and Renal Vasculature in a Porcine Model
2015
Rationale Recently, the efficacy of renal denervation (RDN) has been debated. It is discussed whether RDN is able to adequately target the renal nerves. Objective We aimed to investigate how effective RDN was by means of functional hemodynamic measurements and nerve damage on histology. Methods and Results We performed hemodynamic measurements in both renal arteries of healthy pigs using a Doppler flow and pressure wire. Subsequently unilateral denervation was performed, followed by repeated bilateral hemodynamic measurements. Pigs were terminated directly after RDN or were followed for 3 weeks or 3 months after the procedure. After termination, both treated and control arteries were prepar…
On the Number of Measurements Necessary to Assess Regional Cerebral Blood Flow by Local Laser Doppler Recordings: A Simulation Study with Data from 4…
1995
Laser Doppler fluxmetry may improve the monitoring of cortical blood flow in neurosurgical patients. So far, however, the variability of laser Doppler readings found in the cerebral cortex has prevented a consequent usage of the technique in clinical practice. The current report analyzes the regional variability of laser Doppler readings from experimental animals. Typical frequency histograms of observed flow values display non-Gaussian distributions. A simulation technique is used to assess the number of measuring sites required for valid estimates of regional cortical flow. From a total of 990 local flow measurements from 45 rabbits random samples of sizes between 5 and 100 were repeatedl…
Muscle Free Fatty-Acid Uptake Associates to Mechanical Efficiency During Exercise in Humans
2018
Intrinsic factors related to muscle metabolism may explain the differences in mechanical efficiency (ME) during exercise. Therefore, this study aimed to investigate the relationship between muscle metabolism and ME. Totally 17 healthy recreationally active male participants were recruited and divided into efficient (EF; n = 8) and inefficient (IE; n = 9) groups, which were matched for age (mean ± SD 24 ± 2 vs. 23 ± 2 years), BMI (23 ± 1 vs. 23 ± 2 kg m−2), physical activity levels (3.4 ± 1.0 vs. 4.1 ± 1.0 sessions/week), and V˙O2peak (53 ± 3 vs. 52 ± 3 mL kg−1 min−1), respectively, but differed for ME at 45% of V˙O2peak intensity during submaximal bicycle ergometer test (EF 20.5 ± 3.5 vs. I…
Chronifizierte paranoid-halluzinatorische Psychose als Erstmanifestation einer HIV-Infektion?
2008
In a 36-year-old patient an acute onset of psychosis occurred, probably due to HIV infection. For one year HIV-infection with reduced T4/T8 ratio had been known without clinical manifestation (stage IV B of the CDC-classification). He developed chronic delusional hallucinations, which persisted for more than one year in spite of adequate psychoactive drug therapy. So far AIDS-related dementia has not become evident. Focal lesions caused by opportunistic infections or tumour were excluded by computed tomography and magnetic resonance imaging. The latter revealed several small lesions and the brain scan showed a nonhomogeneous pattern of cerebral blood flow. CSF-examination disclosed a mild l…
Neural conservation in skull base surgery
2002
Surgical treatment of lesions of the skull base carries significant risk to the functioning of the cerebral hemispheres, brainstem, and cranial nerves. This risk is due to both (1) problems associated with maintaining an adequate blood flow while exposing and removing the tumor and (2) direct or indirect trauma to the brain, perineural tissues, and cranial nerves. These risks may be reduced if information about possible implications of surgical maneuvers on the cerebral blood flow and on the function of the patient’s CNS and cranial nerves is available and can be monitored during surgery of the skull base. The use of EMG neuromonitoring for the facial nerve and of brainstem evoked response …
Changes in the adrenergic mechanisms of cerebral arteries after subarachnoid hemorrhage in goats.
1994
We have examined the effects of experimental subarachnoid hemorrhage (SAH), induced by delivering autologous blood into the subarachnoid space, on the adrenergic mechanisms of the goat cerebrovascular bed. To achieve this, the response to noradrenaline was recorded both in vivo, by measuring cerebral blood flow in unanesthetized animals, and in vitro, by recording isometric tension in isolated cerebral arteries. In addition, we checked the function of adrenergic innervation by measuring the tritium efflux evoked by electrical stimulation in cerebral arteries preloaded with [3H]-noradrenaline, and we examined this innervation by using both fluorescent and electron transmission microscopy. Al…
nrCBF for Timing of Angiography and Operation in Subarachnoid Hemorrhage
1983
Early operation on cerebral aneurysms is demanded not least because of the threat of spasm of the cerebral vessels. As is generally recognized, this is to be expected in a very high percentage within a few days after the first aneurysm hemorrhage and frequently cannot be diagnosed clinically (4, 5). Many neurosurgeons have rated the risk of operating in the presence of vasospasm so high that, like C.G. DRAKE in 1975 (2), they demanded control angiography with its own risk, especially in existing vasospasm in early angiography and the aneurysm operation itself could not take place rapidly.