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Circulation Journal : Official Journal... 2016
Topics: Animals; Blood Circulation; Humans; Periodicals as Topic
PubMed: 26658432
DOI: 10.1253/circj.CJ-66-0113 -
Journal of Applied Physiology... Oct 2005Short-term cardiovascular responses to postural change from sitting to standing involve complex interactions between the autonomic nervous system, which regulates blood...
Short-term cardiovascular responses to postural change from sitting to standing involve complex interactions between the autonomic nervous system, which regulates blood pressure, and cerebral autoregulation, which maintains cerebral perfusion. We present a mathematical model that can predict dynamic changes in beat-to-beat arterial blood pressure and middle cerebral artery blood flow velocity during postural change from sitting to standing. Our cardiovascular model utilizes 11 compartments to describe blood pressure, blood flow, compliance, and resistance in the heart and systemic circulation. To include dynamics due to the pulsatile nature of blood pressure and blood flow, resistances in the large systemic arteries are modeled using nonlinear functions of pressure. A physiologically based submodel is used to describe effects of gravity on venous blood pooling during postural change. Two types of control mechanisms are included: 1) autonomic regulation mediated by sympathetic and parasympathetic responses, which affect heart rate, cardiac contractility, resistance, and compliance, and 2) autoregulation mediated by responses to local changes in myogenic tone, metabolic demand, and CO(2) concentration, which affect cerebrovascular resistance. Finally, we formulate an inverse least-squares problem to estimate parameters and demonstrate that our mathematical model is in agreement with physiological data from a young subject during postural change from sitting to standing.
Topics: Autonomic Nervous System; Blood Circulation; Blood Pressure; Cerebrovascular Circulation; Homeostasis; Humans; Linear Models; Models, Cardiovascular; Posture
PubMed: 15860687
DOI: 10.1152/japplphysiol.00177.2005 -
Artificial Organs Aug 2020Having physiological correct flow waveforms is a key feature for experimental studies of blood flow, especially in the process of developing and testing a new medical...
Having physiological correct flow waveforms is a key feature for experimental studies of blood flow, especially in the process of developing and testing a new medical device such as stent, mechanical heart valve, or any implantable medical device that involves circulation of blood through the device. It is also a critical part of a perfusion system for cardiopulmonary bypass and extracorporeal membrane oxygenation procedures. This study investigated the feasibility of a novel roller pump for use in experimental flow phantoms. Flow rates of carotid flow profile measured directly with the ultrasonic flow meter matched well with the reference flow rates programmed into the machine with similarity index of 0.97 and measured versus programmed flow rates at specific time-points of peak systolic velocity (PSV): 0.894 vs 0.880, end systolic velocity (ESV): 0.333 vs 0.319, and peak diastolic velocity (PDV): 0.514 vs 0.520 L/min. Flow rates derived from video analysis of the pump motion for carotid, suprarenal, and infrarenal flows also matched well with references with similarity indices of 0.99, 0.99, and 0.96, respectively. Measured flow rates (mean/standard deviation) at PSV, ESV, and PDV time-points for carotid: 0.883/0.016 vs 0.880, 0.342/0.007 vs 0.319, and 0.485/0.009 vs 0.520; suprarenal: 3.497/0.014 vs 3.500, 0.004/0.003 vs 0, and 1.656/0.073 vs 1.453; infrarenal: 4.179/0.024 vs 4.250, -1.147/0.015 vs -1.213, and 0.339/0.017 vs 0.391 L/min, respectively. The novel roller pump is suitable for benchtop testing of physiological flow.
Topics: Blood Circulation; Carotid Arteries; Heart-Assist Devices; Humans; Models, Biological; Prosthesis Design; Renal Artery
PubMed: 32065666
DOI: 10.1111/aor.13670 -
Circulation Journal : Official Journal... Dec 2016
Topics: Animals; Blood Circulation; Humans; Periodicals as Topic
PubMed: 27941301
DOI: 10.1253/circj.CJ-66-0136 -
Journal of Clinical Hypertension... Apr 2010The two most common vital signs, ie, pulse and blood pressure (BP), are obtained to seek guidance in clinical management of patients in virtually all primary care... (Review)
Review
The two most common vital signs, ie, pulse and blood pressure (BP), are obtained to seek guidance in clinical management of patients in virtually all primary care practices. Even a cursory glance at their values, whether it is within a person over time or between patients on a particular day, reflects an amazing degree of variability. In this brief editorial we provide a focused review of the assessment and the importance of variability in within-patient heart rate and BP and conclude with a few thoughts about the discordance in significance attached to these ubiquitous clinical measures.
Topics: Blood Circulation; Blood Pressure; Blood Pressure Monitoring, Ambulatory; Cardiovascular Diseases; Circadian Rhythm; Heart Rate; Humans
PubMed: 20433549
DOI: 10.1111/j.1751-7176.2009.00262.x -
Circulation Research Apr 2019
Topics: Blood Circulation; Education; History, 16th Century; History, 17th Century; Italy; United Kingdom
PubMed: 30973803
DOI: 10.1161/CIRCRESAHA.119.314976 -
Journal of the Royal Society of Medicine Dec 2007Even though Lazarus phenomenon is rare, it is probably under reported. There is no doubt that Lazarus phenomenon is a reality but so far the scientific explanations have... (Review)
Review
Even though Lazarus phenomenon is rare, it is probably under reported. There is no doubt that Lazarus phenomenon is a reality but so far the scientific explanations have been inadequate. So far the only plausible explanation at least in some cases is auto-PEEP and impaired venous return. In patients with PEA or asystole, dynamic hyperinflation should considered as a cause and a short period of apnoea (30-60 seconds) should be tried before stopping resuscitation. Since ROSC occurred within 10 minutes in most cases, patients should be passively monitored for at least 10 minutes after the cessation of CPR before confirming death.
Topics: Blood Circulation; Cardiopulmonary Resuscitation; Heart Arrest; Humans; Recovery of Function; Time Factors
PubMed: 18065707
DOI: 10.1177/0141076807100012013 -
Ultrasound in Obstetrics & Gynecology :... Apr 2006
Topics: Adrenal Glands; Animals; Blood Circulation; Brain; Fetal Heart; Fetus; Heart Septum; Homeostasis; Humans; Liver; Models, Animal; Oxygen; Regional Blood Flow; Sheep
PubMed: 16565990
DOI: 10.1002/uog.2762 -
Medicine Sep 2019Climacteric women experience various disorders, including hot flush, depression, insomnia, arthralgia, and hand and foot numbness. Dangguijakyaksan is among the most...
Effects of dangguijakyaksan on lower-extremity blood circulation disturbances in climacteric and postmenopausal women: Study protocol for a randomized, double-blind, placebo-controlled pilot trial.
BACKGROUND
Climacteric women experience various disorders, including hot flush, depression, insomnia, arthralgia, and hand and foot numbness. Dangguijakyaksan is among the most common treatments for climacteric syndrome, and its effect on depression, insomnia, hot flush and quality of life (QOL) in climacteric women has been reported multiple times. A recent animal study found dangguijakyaksan decreased serum lipid factors and improved blood circulation in a menopausal rat model; however, these effects have not been assessed in clinical trials. This study aims to assess the clinical effects and safety of dangguijakyaksan for lower-extremity blood circulation disturbances in climacteric women.
METHODS
This is a single-center, randomized, double-blinded, placebo-controlled pilot study that will be conducted at Dunsan Korean Medicine Hospital at Daejeon University. Forty-six climacteric women with lower-extremity blood circulation disturbances will be recruited and randomized (1:1) into either the dangguijakyaksan or placebo group. After 8 weeks of administration, the effects and safety of dangguijakyaksan will be assessed.The primary outcome is the visual analogue scale for lower-extremity blood circulation disturbances, and it will be assessed on visits 1, 2, and 3. The secondary outcomes, Kupperman's index and blood deficiency scoring system, will be assessed on visits 1, 2, and 3, and accelerated photoplethysmography and digital infrared thermal imaging will be performed on visits 1 and 3. Moreover, blood lipid profile, follicle-stimulating hormone, and estradiol levels will be measured at the screening visit and visit 3. Blood tests will be performed at the screening visit and visit 3 to assess the safety of dangguijakyaksan. Statistical analysis will be performed using R-3.3.3 (Another Canoe), and within-group study variable differences after drug administration will be analyzed using paired t-test or Wilcoxon signed-rank test.
DISCUSSION
We expect to confirm the effects and safety of dangguijakyaksan on lower-extremity blood circulation disturbances in menopause, which would provide foundational data for planning subsequent studies.
Topics: Blood Circulation; Cardiovascular Agents; Climacteric; Double-Blind Method; Drugs, Chinese Herbal; Female; Humans; Lower Extremity; Middle Aged; Pilot Projects; Randomized Controlled Trials as Topic
PubMed: 31517823
DOI: 10.1097/MD.0000000000017039 -
Journal of Cellular and Molecular... May 2010It has been known for some considerable time that sustained hypertension changes the circulatory architecture both in the heart and blood vessels. The histopathological... (Review)
Review
It has been known for some considerable time that sustained hypertension changes the circulatory architecture both in the heart and blood vessels. The histopathological alterations are of considerable interest because once they have developed they appear to carry an adverse prognostic risk. In the heart it is apparent that there is hypertrophy. This extends also to the large- and medium-sized blood vessels but at the level of the smaller arteries that contribute to vascular resistance, this is not the case: it is clear that the physiological response to higher pressures is a change in the positional conformation of the pre-existing tissue constituents and as a result of this the lumen is narrowed. This brief review looks at our knowledge in this area and attempts to clarify our understanding of how hypertension brings these about and what happens when these homeostatic mechanisms break down. From a therapeutic perspective it appears imperative to control blood pressure in an attempt to reverse or prevent such alterations to cardiovascular structure. Our knowledge is fast expanding in this field and it is only to be anticipated that as detection methodology improves everyday practice will alter as we profile our patients in terms of structural alterations in the ventricle and blood vessels.
Topics: Arteries; Blood Circulation; Humans; Hypertension; Hypertrophy
PubMed: 20455998
DOI: 10.1111/j.1582-4934.2010.01080.x