scholarly journals Cuff-Method Thigh Arterial Occlusion Counteracts Cerebral Hypoperfusion Against the Push–Pull Effect in Humans

2021 ◽  
Vol 12 ◽  
Author(s):  
Changyang Xing ◽  
Yuan Gao ◽  
Xinpei Wang ◽  
Wenjuan Xing ◽  
Yunnan Liu ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
High Performance ◽  
Cerebral Blood Flow Velocity ◽  
Blood Pressure Response ◽  
Peripheral Resistance ◽  
Arterial Occlusion ◽  
Resistance Index ◽  
Systemic Blood Pressure ◽  
Cerebral Hypoperfusion

Exposure to acute transition from negative (−Gz) to positive (+ Gz) gravity significantly impairs cerebral perfusion in pilots of high-performance aircraft during push—pull maneuver. This push—pull effect may raise the risk for loss of vision or consciousness. The aim of the present study was to explore effective countermeasures against cerebral hypoperfusion induced by the push—pull effect. Twenty healthy young volunteers (male, 21 ± 1 year old) were tested during the simulated push–pull maneuver by tilting. A thigh cuff (TC) pressure of 200 mmHg was applied before and during simulated push—pull maneuver (−0.87 to + 1.00 Gz). Beat-to-beat cerebral and systemic hemodynamics were measured continuously. During rapid −Gz to + Gz transition, mean cerebral blood flow velocity (CBFV) was decreased, but to a lesser extent, in the TC bout compared with the control bout (−3.1 ± 4.9 vs. −7.8 ± 4.4 cm/s, P < 0.001). Similarly, brain-level mean blood pressure showed smaller reduction in the TC bout than in the control bout (−46 ± 12 vs. −61 ± 13 mmHg, P < 0.001). The systolic CBFV was lower but diastolic CBFV was higher in the TC bout. The systemic blood pressure response was blunted in the TC bout, along with similar heart rate increase, smaller decrease, and earlier recovery of total peripheral resistance index than control during the gravitational transition. These data demonstrated that restricting thigh blood flow can effectively mitigate the transient cerebral hypoperfusion induced by rapid shift from −Gz to + Gz, characterized by remarkable improvement of cerebral diastolic flow.

Control of Blood Pressure and the Distribution of Blood Flow

1991 ◽  
Vol 7 (S1) ◽  
pp. 79-84 ◽  
Author(s):  
Hans T. Versmold
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cardiac Output ◽  
Peripheral Resistance ◽  
Systemic Blood Pressure ◽  
Adrenergic Innervation ◽  
Systemic Blood ◽  
Low Cardiac Output ◽  
Neurohumoral Control ◽  
The Brain

Systemic blood pressure (BP) is the product of cardiac output and total peripheral resistance. Cardiac output is controlled by the heart rate, myocardial contractility, preload, and afterload. Vascular resistance (vascular hindrance × viscosity) is under local autoregulation and general neurohumoral control through sympathetic adrenergic innervation and circulating catecholamines. Sympathetic innovation predominates in organs receivingflowin excess of their metabolic demands (skin, splanchnic organs, kidney), while innervation is poor and autoregulation predominates in the brain and heart. The distribution of blood flow depends on the relative resistances of the organ circulations. During stress (hypoxia, low cardiac output), a raise in adrenergic tone and in circulating catecholamines leads to preferential vasoconstriction in highly innervated organs, so that blood flow is directed to the brain and heart. Catecholamines also control the levels of the vasoconstrictors renin, angiotensin II, and vasopressin. These general principles also apply to the neonate.

Case 31: Hypocapnic Cerebral Hypoperfusion with an Artifact

2019 ◽  
pp. 194-197
Author(s):  
Peter Novak
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Flow Velocity ◽  
Blood Flow Velocity ◽  
Cerebral Blood Flow Velocity ◽  
Cerebral Hypoperfusion ◽  
Autonomic Functions ◽  
Raw Data

In this patient, the initial decline in blood pressure at the tilt onset was physiologic since it was accompanied by the decline in cerebral blood flow velocity and heart rate responses. The testing revealed normal autonomic functions. It is important always to check the raw data. Blood pressure from the finger cuff is not always accurate.

Systemic Blood Pressure and Cerebral Blood Flow Velocity During Carotid Surgery

1999 ◽  
Vol 47 (06) ◽  
pp. 381-385 ◽  
Author(s):  
G. Grubhofer ◽  
A. Lassnigg ◽  
T. Pernerstorfer ◽  
O. Ipsiroglu ◽  
M. Czerny ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Flow Velocity ◽  
Blood Flow Velocity ◽  
Cerebral Blood Flow Velocity ◽  
Systemic Blood Pressure ◽  
Carotid Surgery ◽  
Systemic Blood

Case 30: Hypocapnic Cerebral Hypoperfusion with Paced Breathing

2019 ◽  
pp. 189-193
Author(s):  
Peter Novak
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Blood Flow Velocity ◽  
Cerebral Blood Flow Velocity ◽  
Cerebral Hypoperfusion ◽  
Shortness Of Breath ◽  
Paced Breathing ◽  
Cerebral Vasoconstriction ◽  
Patient Reported

In this patient, cerebral blood flow velocity (CBFv) was reduced by 38% during the tilt. Decline in CBFv was due to hypocapnia-induced cerebral vasoconstriction, typical for hypocapnic cerebral hypoperfusion (HYCH). Patient reported dizziness, shortness of breath, and confusion during the tilt. Blood pressure during tilt showed prominent oscillations characteristic of hypovolemia.

Justification of Increasing the Blood Flow Velocity in the Arteries of the Thyroid Gland in Autoimmune Thyroiditis as a Reflection of Endothelial Changes Due to Inflammatory Status

2018 ◽  
Vol 15 (1) ◽  
pp. 61-65
Author(s):  
Nataliia I. Chekalina ◽  
Yurii H. Burmak ◽  
Yeuhen Ye. Petrov ◽  
Zinaiida O. Borysova ◽  
Tetiana A. Trybrat ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Flow Velocity ◽  
Autoimmune Thyroiditis ◽  
Blood Flow Velocity ◽  
Carotid Arteries ◽  
Resistance Index ◽  
Systemic Blood Pressure ◽  
Healthy Individuals ◽  
Systemic Blood

Objective: The aim of the research was to determine the dependence of the blood flow velocity in the thyroid arteries in patients with Autoimmune Thyroiditis (AIT) on the presence of atherosclerotic carotid disease and the level of systemic blood pressure. Methods: The research involved 20 patients with AIT in euthyroid state, 30 patients AIT in euthyroid state with stable Coronary Heart Disease (CHD), 30 patients with stable CHD and 30 healthy individuals. Participants of the research were examined using ultrasound of carotid arteries and inferior thyroid arteries. Parameters of blood flow velocity were compared with the level of systemic blood pressure. Results: In AIT peak systolic velocity and resistance index in the inferior thyroid arteries were significantly higher than in healthy individuals and patients with CHD (p<0.05). In patients with CHD velocity parameters in carotid arteries were high, unlike in the healthy individuals and patients with AIT (p<0.05). In patients with AIT without CHD the atherosclerotic changes of carotid arteries were not found. Increased systemic blood pressure was noticed in all patients with CHD without significant differences between groups. Conclusion: The value of peak systolic velocity and resistance index of inferior thyroid arteries in autoimmune thyroiditis are noticed even with euthyroidism and do not depend on systemic blood pressure and atherosclerosis of carotid arteries. Increasing the thyroid arterial blood flow velocity parameters should be considered as sign of an active inflammatory period AIT, where advanced fibrosis is not present.

Ultrasound features of peripheral angiodistonic syndrome of the upper extremities in vibration disease

2020 ◽  
Vol 60 (11) ◽  
pp. 815-817
Author(s):  
Nadezhda I. Kuprina ◽  
Ekaterina V. Ulanovskaya ◽  
Olga A. Kochetova
Keyword(s):  
Blood Flow ◽  
Heart Defects ◽  
Peripheral Resistance ◽  
Resistance Index ◽  
Ulnar Artery ◽  
Upper Extremities ◽  
Disease Stage ◽  
Peripheral Blood Flow ◽  
Pronounced Increase ◽  
Vibration Disease

Introduction. Vibration disease (VD) is an example of the most common pathology due to the systematic exposure of the worker to intense vibration with sufficient work experience, the main manifestation of which is peripheral angiodystonic syndrome. The aim of study was to learn the features of peripheral blood flow in the arteries of the forearm in vibration disease using the ultrasound method. Materials and methods. The radial and ulnar arteries in patients with vibration disease were examined by ultrasound in B- and PW-mode. These materials present the results of an ultrasound assessment of the speed indicators of the main arteries of the forearm in vibration disease stages 1 and 2. The selection criteria for patients in the study ware the presence of pronounced clinical manifestations of angiodystonic syndrome in vibration disease, confirmed by instrumental research methods and data on the sanitary and hygienic characteristics of working conditions, the absence of cardiovascular chronic diseases (ischemic heart disease, heart defects, rhythm and conduction disturbances), rheumatic, oncological, infectious diseases, osteo-traumatic changes in the upper extremities. Results. The groups of patients with the established diagnosis of vibration disease of 1 and 2 degrees were studied. With vibration disease stage 1 a decrease in the pulse velocity of blood flow was observed in isolation on the ulnar artery and an increase in peripheral resistance (pulsation index and resistance index) in the radial and ulnar arteries symmetrically on both upper extremities. The second stage of vibration disease differed from the first by a more significant decrease in speed indicators both on the ulnar and radial arteries on both sides, symmetrically in combination with a more pronounced increase in peripheral resistance indicators on both main arteries of the forearm (pulsation index and resistance index). The revealed changes were determined with the same frequency in men and women. Conclusions. A significant decrease in speed indicators on the ulnar artery and an increase in peripheral resistance indicators are detected already at the initial stages of vibration disease. Thus, the method of ultrasound examination of the main arteries of the middle caliber of the upper extremities is currently the only available and objective method for examining the vascular system in vibration disease.

RATIONALIZATION FOR THE DIFFERENTIAL DIAGNOSIS OF OVARIAN CANCER AND CHRONIC SALPINGOOPHORITIS IN THE PARAMETERS OF DISINTEGRATION AND NETWORK MODELING CHANGES OF BLOOD FLOW IN UTERINE AND OVARIAN ARTERIES AND VEINS

2017 ◽  
Vol 63 (5) ◽  
pp. 766-769
Author(s):  
Nikolay Agarkov ◽  
Pavel Tkachenko ◽  
Dmitriy Kicha ◽  
Vitaliy Aksenov ◽  
Aleksandr Ivanov ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Blood Flow ◽  
Diagnostic Criteria ◽  
Peripheral Resistance ◽  
Resistance Index ◽  
Diagnostic Process ◽  
Venous Outflow ◽  
Flow Changes ◽  
Arteries And Veins ◽  
Selection Of

Analysis of ultrasonic blood flow changes in uterine and ovarian arteries and veins in 92 patients with ovarian cancer and 87 patients with chronic salpingoophoritis has allowed to identify the leading differential diagnostic criteria, which include minimum diastolic blood flow velocity, resistance index, while fast hyperemia, the index of venous outflow diastolic index and index of peripheral resistance. Based on a selection of leading differential diagnostic criteria for ovarian cancer and chronic salpingoophoritis developed a network model of differentiation of these groups of patients, streamlining the differential diagnostic process

Diurnal variation in time to presyncope and associated circulatory changes during a controlled orthostatic challenge

2010 ◽  
Vol 299 (1) ◽  
pp. R55-R61 ◽  
Author(s):  
N. C. S. Lewis ◽  
G. Atkinson ◽  
S. J. E. Lucas ◽  
E. J. M. Grant ◽  
H. Jones ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Diurnal Variation ◽  
Flow Velocity ◽  
Blood Flow Velocity ◽  
Cerebral Blood Flow Velocity ◽  
Orthostatic Challenge ◽  
Arterial Blood ◽  
Neurally Mediated Syncope

Epidemiological data indicate that the risk of neurally mediated syncope is substantially higher in the morning. Syncope is precipitated by cerebral hypoperfusion, yet no chronobiological experiment has been undertaken to examine whether the major circulatory factors, which influence perfusion, show diurnal variation during a controlled orthostatic challenge. Therefore, we examined the diurnal variation in orthostatic tolerance and circulatory function measured at baseline and at presyncope. In a repeated-measures experiment, conducted at 0600 and 1600, 17 normotensive volunteers, aged 26 ± 4 yr (mean ± SD), rested supine at baseline and then underwent a 60° head-up tilt with 5-min incremental stages of lower body negative pressure until standardized symptoms of presyncope were apparent. Pretest hydration status was similar at both times of day. Continuous beat-to-beat measurements of cerebral blood flow velocity, blood pressure, heart rate, stroke volume, cardiac output, and end-tidal Pco2 were obtained. At baseline, mean cerebral blood flow velocity was 9 ± 2 cm/s (15%) lower in the morning than the afternoon ( P < 0.0001). The mean time to presyncope was shorter in the morning than in the afternoon (27.2 ± 10.5 min vs. 33.1 ± 7.9 min; 95% CI: 0.4 to 11.4 min, P = 0.01). All measurements made at presyncope did not show diurnal variation ( P > 0.05), but the changes over time (from baseline to presyncope time) in arterial blood pressure, estimated peripheral vascular resistance, and α-index baroreflex sensitivity were greater during the morning tests ( P < 0.05). These data indicate that tolerance to an incremental orthostatic challenge is markedly reduced in the morning due to diurnal variations in the time-based decline in blood pressure and the initial cerebral blood flow velocity “reserve” rather than the circulatory status at eventual presyncope. Such information may be used to help identify individuals who are particularly prone to orthostatic intolerance in the morning.

Effect of the Ace Inhibitor Ceronapril on Cerebral Blood flow in Hypertensive Patients

1996 ◽  
Vol 30 (6) ◽  
pp. 578-582 ◽  
Author(s):  
Neal R Cutler ◽  
John J Sramek ◽  
Azucena Luna ◽  
Ismael Mena ◽  
Eric P Brass ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Diastolic Blood Pressure ◽  
Arterial Blood Pressure ◽  
Mean Arterial Blood Pressure ◽  
Enzyme Inhibitor ◽  
Blood Pressure Response ◽  
Combined Therapy ◽  
Arterial Blood

Objective To assess the effect of the angiotensin-converting enzyme inhibitor ceronapril on cerebral blood flow (CBF) in patients with moderate hypertension. Design Patients received chlorthalidone 25 mg for 4 weeks, and if diastolic blood pressure remained in the range of 100–115 mm Hg, they were given titrated doses of ceronapril (10–40 mg/d based on blood pressure response) in addition to chlorthalidone for 9 weeks. Setting Outpatient research clinic. Subjects Eligible patients had moderate essential hypertension (diastolic blood pressure 100–115 mm Hg) assessed when the patients were receiving no medications. Thirteen patients were entered into the study; 1 withdrew for reasons unrelated to the study drug. Twelve patients (11 men, 1 woman; mean age 52 y) completed the study. Intervention Ceronapril, given with chlorthalidone. Main Outcome Measures CBF measurements were taken at the start and end of ceronapril therapy using intravenous 133Xe; blood pressures were determined weekly. Results Mean arterial blood pressure decreased from 130 ± 4 to 120 ±7 mm Hg after 4 weeks of chlorthalidone administration, and fell further to 108 ± 8 mm Hg after an additional 9 weeks of combined chlorthalidone-ceronapril therapy (p < 0.05). CBF fell from 44 ± 15 to 34 ± 5 mL/min/100 g during the 9 weeks of combined therapy (p = 0.05). No adverse effects consistent with decreased CBF were observed. The decrease in CBF was not linearly correlated with the change in systemic blood pressure, but was strongly correlated (r = –0.937; p < 0.001) with the initial CBF. Conclusions The decrease in mean arterial blood pressure was not associated with a decrease in CBF. Patients with high CBF may be predisposed to a decrease in CBF when treated with ceronapril and chlorthalidone.

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