Search results for "Pulsatile flow"
showing 10 items of 40 documents
Collapsibility of the internal jugular veins in the lateral decubitus body position: A potential protective role of the cerebral venous outflow again…
2019
Recent research has revealed that patients with neurodegenerative disease sleep longer in the supine position, while healthy controls prefer sleeping in the lateral decubitus position. Thus, sleeping in the lateral position seems to be protective against neurodegeneration. It has also been suggested that a protective role of this body position could be associated with better cerebral venous drainage in this body position, which results in more active glymphatic system of the brain (the system responsible for clearance of the cerebral tissue from waste products, e.g. amyloid-β). Since no published evidence exists regarding venous outflow from the cranial cavity in the lateral decubitus posit…
Deficient pulsatile thyrotropin secretion in the low-thyroid-hormone state of severe non-thyroidal illness
1994
Custro N, Scafidi V, Gallo S, Notarbartolo A. Deficient pulsatile thyrotropin secretion in the low-thyroid-hormone state of severe non-thyroidal illness. Eur J Endocrinol 1994;130:132–6. ISSN 0804–4643. Twenty-four-hour thyrotropin (TSH) profiles in eight severely ill patients were compared with those of six healthy subjects. The profiles were assessed using the cosinor method to evaluate circadian variations and using the Pulsar algorithm to analyze episodic secretion. In the normal subjects, the typical periodicity of TSH secretion showed a mean level in the rhythm (mesor) of 2.03 mU/l, The amplitude (half the extent of rhythmic change in the cycle) was 0.58 mU/l; the acrophase (the delay…
Optical noninvasive monitoring of skin blood pulsations
2005
Time-resolved detection and analysis of skin backscattered optical signals (remission photoplethysmography or PPG) provide rich information on skin blood volume pulsations and can serve for reliable cardiovascular assessment. Single- and multiple-channel PPG concepts are discussed. Simultaneous data flow from several locations on the human body allows us to study heartbeat pulse-wave propagation in real time and to evaluate vascular resistance. Portable single-, dual-, and four-channel PPG monitoring devices with special software have been designed for real-time data acquisition and processing. The prototype devices have been clinically studied, and their potential for monitoring heart arrh…
Accuracy of the fetal cerebroplacental ratio for the detection of intrapartum compromise in nonsmall fetuses
2018
Objective: To study the accuracy of the cerebroplacental ratio (CPR) for the detection of intrapartum fetal compromise (IFC) in fetuses growing over the 10th centile.Methods: This was a prospective...
Arterial stiffness indexes in acute ischemic stroke: Relationship with stroke subtype
2010
INTRODUCTION: No study has evaluated both arterial stiffness indexes (PWV and Aix) in patients with an acute cerebrovascular event. The aim of our study was to evaluate arterial stiffness indexes in subjects with acute ischemic stroke and to evaluate the relationship between these indexes and other clinical and laboratory variables. MATERIALS AND METHODS: We enrolled all consecutive patients with a diagnosis of acute ischemic stroke admitted to the Internal Medicine Department at the University of Palermo between November 2006 and January 2009, and hospitalized control patients without a diagnosis of acute ischemic stroke. The type of acute ischemic stroke was classified according to the TO…
The preoperative assessment of stroke risk in lesions involving the internal carotid artery.
1995
Patients with vascular or tumourous lesions involving the internal carotid artery are at risk of damage or occlusion of this vessel during surgical or endovascular procedures. To assess the stroke risk transcranial Doppler aided carotid compression tests were performed in 82 patients. Based on changes of blood flow velocity (BFV), pulsatility index, systolic/diastolic ratio and length of transient hyperaemic response three groups could be differentiated. Patients in group A (31%) showed only a slight reaction of BFV and were at minimal risk in case of carotid occlusion. Patients in group B (52%) underwent a distinct decrease of Doppler readings with partial improvement and were considered t…
Relationship of Metabolic Syndrome With Pulse Pressure in Patients With Essential Hypertension
2006
BACKGROUND: Pulse pressure is largely dependent on arterial stiffness. Recent studies have documented reduced large artery compliance in nondiabetic subjects with metabolic syndrome (MS). The aim of our study was to analyze, in a group of patients with essential hypertension and without diabetes mellitus, the influence of MS on clinic and 24-h pulse pressures. METHODS: A total of 528 hypertensive subjects, aged 18 to 72 years, who were free of cardiovascular and renal diseases were enrolled. Of the subjects, 41% had MS. In all subjects routine blood chemistry, echocardiographic examination, and 24-h ambulatory blood pressure monitoring were performed. RESULTS: When compared with subjects wi…
Feasibility of cuff-free measurement of systolic and diastolic arterial blood pressure
2011
We validated a prototype cuff-free device for noninvasive estimation of blood pressure (BP). The system assumed a linear relation between BP values and the inverse of arterial blood pulse transit time, measured as time interval between the R wave on the electrocardiograph and the onset of the peripheral pulse wave on a finger plethysmogram. Thirty-three healthy subjects were analyzed at rest and during increasing stress exercise. To estimate subject-specific linear model parameters, the system was calibrated ad personam with reference to BP measures obtained by a cuff sphygmomanometer. High correlation values (R2= 0.89 and 0.78 for systolic and diastolic BP, respectively) and differences co…
Pulsatile and steady 24-h blood pressure components as determinants of left ventricular mass in young and middle-aged essential hypertensives
2003
In order to explore the relations between left ventricular mass (LVM) and the pulsatile (pulse pressure) and steady (mean pressure) components of the blood pressure (BP) curve, 304 young and middle-aged essential hypertensive patients were studied by means of 24-h ambulatory BP monitoring and echocardiography. In the overall study population, both the BP components showed significant correlations with LVM. These correlations were unevenly distributed in the subgroups of subjects younger and in those older than 50 years. While in this latter subgroup, in multivariate analysis, both 24-h mean BP (24-MBP) (beta = 0.27; P = 0.008) and 24-h pulse pressure (24-h PP) (beta = 0.23; P = 0.02) were a…
Blood flow velocity waveforms of the fetal middle cerebral artery in a normal population: reference values from 18 weeks to 42 weeks of gestation
2002
The aim of this prospective cross-sectional study was to establish new Doppler reference curves for peak blood flow velocities (Vmax, Vmean, Vmin) and impedance indices (PI, RI) of the middle cerebral artery at 18-42 weeks of gestation by an automatic wave form analysis integrated into the ultrasound device. In 962 low-risk pregnancies, blood flow velocities were derived from the middle cerebral artery with pulsed color Doppler ultrasonography. Reference curves were constructed for the individual parameters based on a growth function from a four-parameter class of monotonic continuous functions according to the smallest square principle for maximum blood flow velocities, as well as on a pol…