scholarly journals Maintenance of High Blood Pressure and Early Establishment of Pulsatile Blood Flow to the Spinal Cord during Thoracoabdominal Aortic Repair

2018 ◽  
Vol 08 (10) ◽  
pp. 175-188
Author(s):  
Koji Furukawa ◽  
Eisaku Nakamura ◽  
Masanori Nishimura ◽  
Hirohito Ishii ◽  
Kunihide Nakamura
Keyword(s):  
Blood Pressure ◽  
Spinal Cord ◽  
Blood Flow ◽  
High Blood Pressure ◽  
Pulsatile Blood Flow ◽  
Aortic Repair ◽  
Early Establishment

COMPARISON OF ANTIHYPERTENSIVE EFFECT OF MOXONIDINE VERSUS CLONIDINE IN RENAL FAILURE PATIENTS.

2018 ◽  
Vol 6 (9) ◽  
Author(s):  
DR.MATHEW GEORGE ◽  
DR.LINCY JOSEPH ◽  
MRS.DEEPTHI MATHEW ◽  
ALISHA MARIA SHAJI ◽  
BIJI JOSEPH ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Renal Failure ◽  
Blood Flow ◽  
Blood Vessel ◽  
Blood Vessels ◽  
High Blood Pressure ◽  
Antihypertensive Effect ◽  
The Body ◽  
Ability To Work ◽  
Blood Flows

Blood pressure is the force of blood pushing against blood vessel walls as the heart pumps out blood, and high blood pressure, also called hypertension, is an increase in the amount of force that blood places on blood vessels as it moves through the body. Factors that can increase this force include higher blood volume due to extra fluid in the blood and blood vessels that are narrow, stiff, or clogged(1). High blood pressure can damage blood vessels in the kidneys, reducing their ability to work properly. When the force of blood flow is high, blood vessels stretch so blood flows more easily. Eventually, this stretching scars and weakens blood vessels throughout the body, including those in the kidneys.

scholarly journals Cerebral Autoregulation during Postural Change in Patients with Cervical Spinal Cord Injury—A Carotid Duplex Ultrasonography Study

Diagnostics ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1321
Author(s):  
Joo-Hyun Kee ◽  
Jun-Hyeong Han ◽  
Chang-Won Moon ◽  
Kang Hee Cho
Keyword(s):  
Blood Pressure ◽  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Blood Flow ◽  
Cerebral Autoregulation ◽  
Duplex Ultrasonography ◽  
Postural Change ◽  
Carotid Duplex ◽  
Cord Injury ◽  
Carotid Duplex Ultrasonography

Patients with a spinal cord injury (SCI) frequently experience sudden falls in blood pressure during postural change. Few studies have investigated whether the measurement of blood flow velocity within vessels can reflect brain perfusion during postural change. By performing carotid duplex ultrasonography (CDU), we investigated changes in cerebral blood flow (CBF) during postural changes in patients with a cervical SCI, determined the correlation of CBF change with presyncopal symptoms, and investigated factors affecting cerebral autoregulation. We reviewed the medical records of 100 patients with a cervical SCI who underwent CDU. The differences between the systolic blood pressure, diastolic blood pressure, and CBF volume in the supine posture and after 5 min at 50° tilt were evaluated. Presyncopal symptoms occurred when the blood flow volume of the internal carotid artery decreased by ≥21% after tilt. In the group that had orthostatic hypotension and severe CBF decrease during tilt, the body mass index and physical and functional scores were lower than in other groups, and the proportion of patients with a severe SCI was high. The higher the SCI severity and the lower the functional score, the higher the possibility of cerebral autoregulation failure. CBF should be assessed by conducting CDU in patients with a high-level SCI.

Increased vascular resistance in paralyzed legs after spinal cord injury is reversible by training

2002 ◽  
Vol 93 (6) ◽  
pp. 1966-1972 ◽  
Author(s):  
Maria T. E. Hopman ◽  
Jan T. Groothuis ◽  
Marcel Flendrie ◽  
Karin H. L. Gerrits ◽  
Sibrand Houtman
Keyword(s):  
Blood Pressure ◽  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Blood Flow ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Vascular Resistance ◽  
Arterial Blood Flow ◽  
Arterial Blood ◽  
Cord Injury

The purpose of the present study was to determine the effect of a spinal cord injury (SCI) on resting vascular resistance in paralyzed legs in humans. To accomplish this goal, we measured blood pressure and resting flow above and below the lesion (by using venous occlusion plethysmography) in 11 patients with SCI and in 10 healthy controls (C). Relative vascular resistance was calculated as mean arterial pressure in millimeters of mercury divided by the arterial blood flow in milliliters per minute per 100 milliliters of tissue. Arterial blood flow in the sympathetically deprived and paralyzed legs of SCI was significantly lower than leg blood flow in C. Because mean arterial pressure showed no differences between both groups, leg vascular resistance in SCI was significantly higher than in C. Within the SCI group, arterial blood flow was significantly higher and vascular resistance significantly lower in the arms than in the legs. To distinguish between the effect of loss of central neural control vs. deconditioning, a group of nine SCI patients was trained for 6 wk and showed a 30% increase in leg blood flow with unchanged blood pressure levels, indicating a marked reduction in vascular resistance. In conclusion, vascular resistance is increased in the paralyzed legs of individuals with SCI and is reversible by training.

scholarly journals Regional Neurovascular Coupling and Cognitive Performance in Those with Low Blood Pressure Secondary to High-Level Spinal Cord Injury: Improved by Alpha-1 Agonist Midodrine Hydrochloride

2014 ◽  
Vol 34 (5) ◽  
pp. 794-801 ◽  
Author(s):  
Aaron A Phillips ◽  
Darren ER Warburton ◽  
Philip N Ainslie ◽  
Andrei V Krassioukov
Keyword(s):  
Blood Pressure ◽  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Blood Flow ◽  
Cognitive Function ◽  
Neurovascular Coupling ◽  
Control Group ◽  
Cord Injury ◽  
Low Blood Pressure ◽  
High Level

Individuals with high-level spinal cord injury (SCI) experience low blood pressure (BP) and cognitive impairments. Such dysfunction may be mediated in part by impaired neurovascular coupling (NVC) (i.e., cerebral blood flow responses to neurologic demand). Ten individuals with SCI > T6 spinal segment, and 10 age- and sex-matched controls were assessed for beat-by-beat BP, as well as middle and posterior cerebral artery blood flow velocity (MCAv, PCAv) in response to a NVC test. Tests were repeated in SCI after 10 mg midodrine (alpha1-agonist). Verbal fluency was measured before and after midodrine in SCI, and in the control group as an index of cognitive function. At rest, mean BP was lower in SCI (70 ± 10 versus 92 ± 14 mm Hg; P<0.05); however, PCAv conductance was higher (0.56 ± 0.13 versus 0.39 ± 0.15 cm/second/mm Hg; P<0.05). Controls exhibited a 20% increase in PCAv during cognition; however, the response in SCI was completely absent ( P<0.01). When BP was increased with midodrine, NVC was improved 70% in SCI, which was reflected by a 13% improved cognitive function ( P<0.05). Improvements in BP were related to improved cognitive function in those with SCI ( r2 = 0.52; P<0.05). Impaired NVC, secondary to low BP, may partially mediate reduced cognitive function in individuals with high-level SCI.

Nervous System and Hypertension

1978 ◽  
Vol 55 (s4) ◽  
pp. 45s-56s ◽  
Author(s):  
J. P. Chalmers
Keyword(s):  
Blood Pressure ◽  
Spinal Cord ◽  
Nervous System ◽  
Arterial Pressure ◽  
High Blood Pressure ◽  
Sympathetic Activity ◽  
Experimental Hypertension ◽  
Primary Role ◽  
Noradrenergic Nerves ◽  
Peripheral Sympathetic Activity

1. Presynaptic regulation. The regulation of noradrenaline release by a wide variety of substances acting on presynaptic receptors suggests that local factors may play a greater role in the control of blood pressure than was previously believed and that a number of new approaches to the drug treatment of hypertension could be developed. It also raises the possibility that there might be differences in the presynaptic receptor populations of hypertensive and normotensive subjects or animals. 2. Central nerve pathways. There is a need for more precise delineation of central nerve tracts subserving a cardiovascular function and for greater use of morphological techniques to confirm the reliability of biochemical and physiological experiments in the central nervous system. Two appropriate techniques are described. 3. Models of experimental hypertension. (a) Neurogenic hypertension: interference with baroreceptor afferents can cause a permanent elevation of arterial pressure mediated by increased activity of peripheral sympathetic nerves and of descending noradrenergic nerves terminating in the spinal cord. Catecholamine nerve connections of the nucleus tractus solitarius serve mainly to modulate rather than to mediate baroreceptor reflexes. (b) DOCA—salt hypertension: increased peripheral sympathetic activity is important in both the initiation and the maintenance of this form of hypertension. The decrease in brain-stem noradrenaline turnover found in this model could play a determinant role in the development of the high blood pressure. (c) Renal hypertension: both central and peripheral nervous mechanisms contribute to the development and the early phase of ‘one-kidney’ hypertension in animals. Their role in the maintenance of this form of hypertension is still controversial. (d) Spontaneously hypertensive rats: peripheral and central mechanisms do not appear to have a major role in the maintenance of this form of hypertension. However, it seems possible that centrally evoked increases in peripheral sympathetic activity could be important in the initiation of the high blood pressure. (e) Central catecholamines and blood pressure control; central catecholaminergic nerves do not make up a single homogeneous system. For example, the activity of descending noradrenergic nerves in the spinal cord contributes to an elevation of arterial pressure, whereas the activity of catecholaminergic nerves in the dorsomedial medulla appears to have a depressor effect. 4. Human essential hypertension. (a) There is no good evidence that the nervous system plays the major primary role in the development or maintenance of essential human hypertension. (b) Effective treatment of raised blood pressure through nervous mechanisms requires an understanding of the factors that normally control the pressure and does not necessarily depend on reversing specific nervous processes responsible for producing the increase in pressure.

scholarly journals In Vivo Pulse Wave Measurement Through a Multimode Fiber Diffuse Speckle Analysis System

2021 ◽  
Vol 8 ◽  
Author(s):  
Zhongshuai Teng ◽  
Feng Gao ◽  
Hua Xia ◽  
Wenliang Chen ◽  
Chenxi Li
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Pulse Wave Velocity ◽  
Wave Velocity ◽  
Continuous Monitoring ◽  
Pulse Wave ◽  
Cost Effective ◽  
Multimode Fiber ◽  
Pulsatile Blood Flow

Continuous monitoring of in vivo pulsatile blood flow and pulse wave velocity (PWV) is important for clinical applications. These parameters are correlated with physiological parameters, such as blood pressure and elasticity of blood vessels. A multimode fiber diffuse speckle contrast analysis (MMF-DSCA) system was developed for fast measurement of in vivo pulsatile blood flow and pulse wave velocity. With MMF and CCD sensor, the diffuse speckle could be captured and processed with higher temporal resolution of 3 ms. We also induced for the first time an MMF-DSCA for evaluation of PWV, which allows estimation of the blood pressure continuously. To validate its performance, both phantom and in vivo experiments were conducted. The results demonstrate that MMF-DSCA could achieve fast pulsatile blood flow measurement with detailed information of the pulse wave profile and velocity. Taking the advantages of being simple and cost-effective, the flexible system can be easily adapted for continuous monitoring of vital biosigns, such as heart rate, pulse wave, and blood pressure.

Edema, Fainting, and Strokes

2021 ◽  
pp. 216-240
Author(s):  
Graham Mitchell
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Blood Vessels ◽  
High Blood Pressure ◽  
Fluid Pressure ◽  
Basement Membranes ◽  
Tissue Pressure ◽  
Efficient Mechanisms ◽  
The Brain ◽  
Mediated Reduction

High blood pressure in humans is often associated with heart failure, edema, strokes, and episodes of fainting. Giraffes never show these. Edema, the abnormal collection of fluid in the lower legs, is prevented in giraffes by a combination of thick basement membranes of capillary blood vessels, which probably reduce their permeability to proteins, a very high tissue pressure that resists flow of fluid out of capillaries, and efficient mechanisms for returning blood to the heart. Fainting occurs when blood flow (and thus oxygen and glucose supply) to the brain is reduced. When a giraffe lifts its head after drinking water there is a sudden reduction of blood flow to the head, and fainting should result. Fainting is avoided because the blood flow that remains is diverted completely to the brain by a unique arrangement of blood vessels and nerves, and by structures that maintain the perfusion pressure of the blood flowing through the brain. Strokes can be caused by rupture of small blood vessels in the brain when they are exposed to high blood pressure of the kind reached in the head of a giraffe when it drinks surface water. Rupture of brain blood vessels is prevented in giraffes by mechanisms that reduce pressure. The posture adopted while drinking, baroreceptor-mediated reduction in cardiac output, the effects of the carotid rete, diversion of blood away from the brain, an increase in cerebrospinal fluid pressure, and passive and active constriction of blood vessels, all contribute.

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