AIM To study continuously cerebral blood flow velocity in the middle cerebral artery before, during, and after tube feeding in neonates. METHOD Cerebral blood flow velocity was measured in 14 neonates using a Doppler ultrasound device. Blood pressure, respiration, and oxygen saturation were monitored. RESULTS Mean blood flow velocity decreased from 37 cm/s before feeding to 33 cm/s (P < 0.0...

Transcranial Doppler ultrasonography can map the changes in blood velocity that result from stenosis or occlusion of the middle cerebral artery. To evaluate patterns of collateral blood flow in disease of the middle cerebral artery stem, we used both cerebral angiography and transcranial Doppler ultrasonography to study the systolic blood velocities in both anterior cerebral arteries in 10 cons...

In patients with malignant hypertension, immediate blood pressure reduction is indicated to prevent further organ damage. Because cerebral autoregulatory capacity is impaired in these patients, a pharmacologically induced decline of blood pressure reduces cerebral blood flow with the danger of cerebral hypoperfusion. We compared the reduction in transcranial Doppler-determined middle cerebral a...

BACKGROUND Intermittent negative pressure (INP) applied to the lower leg and foot increases foot perfusion in healthy volunteers. The aim of the present study was to describe the effects of INP to the lower leg and foot on foot macro- and microcirculation in patients with lower extremity peripheral arterial disease (PAD). METHODS In this experimental study, we analyzed foot circulation during...

background: numerical study of angulation effects of renal arteries on blood flow has been of great interest for many researchers. objective: this paper aims at numerically determining the angulation effects of stenosed renal arteries on blood flow velocity and renal mass flow. method: an anatomically realistic model of abdominal aorta and renal arteries is reconstructed from ct-scan images and...

The high blood rate that often occurs in arteries may play a role in artery failure and tortuosity which leads to blackouts, transitory ischemic attacks and other diseases. However, vibration and instability analysis of carotid arteries are lacking. The objective of this study is to investigate the vibration and instability of the carotid arteries conveying blood under axial tension with surrou...

Background: Numerical study of angulation effects of renal arteries on blood flow has been of great interest for many researchers.Objective: This paper aims at numerically determining the angulation effects of stenosed renal arteries on blood flow velocity and renal mass flow.Method: An anatomically realistic model of abdominal aorta and renal arteries is reconstructed from CT-scan images and u...

Although the augmentation of central hemodynamics during human sexual intercourse is well established, dynamic changes in human regional cerebral blood flow have not been reported. Noninvasive transcranial Doppler ultrasonography has been well validated and allows direct, continuous measurement of phasic blood velocity in the human middle cerebral artery (a linear index of regional cerebral blo...

BACKGROUND AND PURPOSE The aim of our study was to evaluate by transcranial Doppler ultrasonography the dynamics of blood flow velocity changes in the middle cerebral artery during and after hypocapnia-induced vasoconstriction in untreated essential hypertensive patients. METHODS Sixteen hypertensive patients (10 men and six women, 29-62 years of age) and 10 healthy control subjects (six men ...