peripheral resistance
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Author(s):  
Brandon G Fico ◽  
Taha Ali Alhalimi ◽  
Hirofumi Tanaka

Breath-hold diving evokes a complex cardiovascular response. The degrees of hypertension induced by the diving reflex are substantial and accentuated by the underwater swimming. This condition provides a circulatory challenge to properly buffer and cushion cardiac pulsations. We determined hemodynamic changes during the diving maneuver. A total of 20 healthy young adults were studied. Hemodynamics were measured during exercise on a cycle ergometer, apnea, face immersion in cold water (trigeminal stimulation), and simulated breath-hold diving. Dynamic arterial compliance (measured by changes in carotid artery diameter via ultrasound divided by changes in carotid blood pressure as assessed by arterial tonometry) increased with simulated diving compared with rest (p=0.007) and was elevated compared with exercise and apnea alone (p<0.01). A significant increase in heart rate was observed with exercise, apnea, and facial immersion when compared with rest (p<0.001). However, simulated diving brought the heart rate down to resting levels. Cardiac output increased with all conditions (p<0.001), with an attenuated response during simulated diving compared with exercise and facial immersion (p<0.05). Mean blood pressure was elevated during all conditions (p<0.001), with a further elevation observed during simulated diving compared with exercise (p<0.001), apnea (p=0.016), and facial immersion (p<0.001). Total peripheral resistance was decreased during exercise and facial immersion compared with rest (p<0.001) but was increased during simulated diving compared with exercise (p<0.001), apnea (p=0.008), and facial immersion (p=0.003). We concluded that central artery compliance is augmented during simulated breath-hold diving to help buffer cardiac pulsations.


Author(s):  
Stephane Laurent ◽  
Claudia Agabiti-Rosei ◽  
Rosa Maria Bruno ◽  
Damiano Rizzoni

Microcirculation and macrocirculation are tightly interconnected into a dangerous cross-link in hypertension. Small artery damage includes functional (vasoconstriction, impaired vasodilatation) and structural abnormalities (mostly inward eutrophic remodeling). These abnormalities are major determinants of the increase in total peripheral resistance and mean blood pressure (BP) in primary hypertension, which in the long term induces large artery stiffening. In turn, large artery stiffening increases central systolic and pulse pressures, which are further augmented by wave reflection in response to the structural alterations in small resistance arteries. Finally, transmission of high BP and flow pulsatility to small resistance arteries further induces functional and structural abnormalities, thus leading to increased total peripheral resistance and mean BP, thus perpetuating the vicious circle. Hyperpulsatility, in addition to higher mean BP, exaggerates cardiac, brain, and kidney damages and leads to cardiovascular, cerebral, and renal complications. The dangerous cross-link between micro and macrocirculation can be reversed into a virtuous one by ACE (angiotensin-converting enzyme) inhibitors, sartans, and calcium channel blockers. These three pharmacological classes are more potent than β-blockers and diuretics for reducing arterial stiffness and small artery remodeling. The same ranking was observed for their effectiveness at reducing left ventricular hypertrophy, preserving glomerular filtration rate, and preventing dementia, suggesting that they can act beyond brachial BP reduction, by breaking the micro/macrocirculation vicious circle.


Author(s):  
Dipak K. Sah ◽  
Farzana Deeba ◽  
Saleha B. Chowdhury

Background: Pre-eclampsia (PE) complicates 2% of pregnancies and may have serious effects on mother and child, which makes it an important threat to public health in both developed and developing countries. Once high-risk women are identified, they can be targeted for more intense prenatal surveillance and preventative measures. Predicting PE in the first trimester requires the use of maternal echocardiography and the uterine artery pulsatility index (UAPI). Objective of the study was to see whether maternal echocardiography and uterine artery Doppler at 11-14 weeks can predict subsequent development of PE in nulliparous women.Methods: This prospective observational cohort study was carried out in outdoor patients of obstetrics and gynecology of Bangabandhu Sheikh Mujib Medical University (BSMMU), with collaboration with department of cardiology, National Institute of Nuclear Medicine and Allied Sciences (NINMAS), BSMMU, Dhaka, during 01 December 2013 to July 2015. A total of 135 healthy nulliparous women at 11-14 weeks of gestation were included in this study. Data was processed and analyzed by statistical package for the social sciences (SPSS) version 24.0.Results: Among 135 patients, two (1.5%) patients developed preeclampsia during 1st follow-up (20-28 weeks) and four (2.9%) patients developed preeclampsia during (29-36 weeks). Mean total peripheral resistance was found to be 1332.0±75.2 dynes/sec/cm5 in preeclampsia and 1157.0±139.2 dynes/sec/cm5 in non preeclamptic pregnancy. The difference between two groups was statistically significant. MAP and total peripheral resistance were statistically significant (p<0.05) between two groups.Conclusions: In first trimester of pregnancy UAPI is the best predictor for detection of PE.


2021 ◽  
Author(s):  
V.A. Golodnova ◽  
S.S. Ananyev ◽  
Y.Y. Bikbaeva ◽  
M.V. Balykin ◽  
I.V. Antipov

Objective: to evaluate changes in systemic and cerebral hemodynamics during percutaneous electrical stimulation of the spinal cord and in combination of electrical stimulation with mechanotherapy. Methodology. The subjects underwent percutaneous electrical stimulation of the spinal cord, the duration of the session was 5 minutes. Mechanotherapy was performed using a treadmill. The subjects performed walking at a power of 25W. for 5 minutes. Hemodynamics was evaluated before and after the electrical stimulation session, as well as before and after the mechanical therapy session on the track in combination with percutaneous electrical stimulation of the spinal cord. To study systemic and regional hemodynamics, a rheograph-polyanalyzer "REAN-POLY" was used. Results. Electrical stimulation of the spinal cord does not lead to significant changes in systemic and cerebral hemodynamics. Percutaneous electrical stimulation of the spinal cord in combination with physical exertion leads to reactive changes in systemic hemodynamics, increased blood filling and venous outflow, against the background of a decrease in peripheral resistance of cerebral vessels. Key words: electrostimulation, percutaneous electrostimulation, mechanotherapy, systemic hemodynamics, regional hemodynamics.


2021 ◽  
Vol 116 ◽  
pp. 104929
Author(s):  
Mirco Rampazzo ◽  
Eleonora Manzoni ◽  
Michele Lionello ◽  
Luigi Di Micco ◽  
Francesca Maria Susin

2021 ◽  
pp. 112972982110528
Author(s):  
Emilie K Hansen ◽  
Kristine Lindhard ◽  
Ditte Hansen

Background: The arteriovenous fistula (AVF) is the preferred vascular access for hemodialysis (HD) treatment and preservation of a stable vascular access is crucial. Long term Far Infrared Radiation (FIR) has been found to increase access flow together with an enhanced maturation and patency of the AVF. The acute effects of FIR on access flow have been sparsely described and the results are contradictory, perhaps due to differences in measurement conditions and other factors of importance for access flow. Methods: Twenty patients in HD with an AVF were included. Each patient was randomized to receive either FIR (FIR group) or no FIR (control group). The acute changes in access flow were investigated in both groups on the second dialysis day of the week and during the first 1.5 h of the dialysis session. Concomitant changes in hemodynamic parameters of importance for access flow were also explored. Results: There was no significant change in access flow in the FIR group compared with the control group (median (Interquartile Range)) (−10 (−413.8; 21.3) ml/min vs −17.5 (−83.8; 76.3) ml/min, p = 0.58). There was no significant difference in any of the hemodynamic parameters between the FIR and the control group; cardiac output (−0.7 (−1.2; −0.2) l/min vs −0.4 (−0.9; 0.1) l/min, p = 0.58), cardiac index (−0.3 (−0.5; −0.1)) l/min/m2 vs −0.3 (−0.4; 0) l/min/m2, p = 0.68), mean arterial pressure (5.5 (−1.8; 8.4) mmHg vs 1.5 (−3; 6.3) mmHg, p = 0.35) and total peripheral resistance (2 (1.8; 3.4) mmHg × min/l vs 1 (−0.3; 3.1) mmHg × min/l, p = 0.12). Conclusion: In this trial, with a highly standardized set-up, one session of FIR did not result in any acute changes in access flow. This was not due to differences in the hemodynamic parameters between the groups.


2021 ◽  
Vol 8 (3) ◽  
pp. 149-154
Author(s):  
Tat’yana A. Kamaeva

PURPOSE: improving the efficiency of diagnosis of placental insufficiency using modern diagnostic methods. MATERIALS AND METHODS: The analysis of individual cards, analysis of the gynecological history and somatic morbidity of 426 pregnant women who did not have somatic pathologies and underwent screenings in accordance with the current regulations were performed. The main group of them consisted of 290 women, who showed signs of chronic placental insufficiency at different stages of pregnancy. The control group consisted of 136 women who had no signs of placental insufficiency throughout their pregnancy. RESULTS: It was revealed that the main reasons for the development of chronic placental insufficiency of the main group are preeclampsia (68.4%), the threat of termination of pregnancy (34.7%), burdened obstetric and gynecological history (32.5%), isoserological incompatibility (25.6%), pyelonephritis during pregnancy (14.2%) and anemia of pregnant women (13.2%). It was revealed that visualization of the fetoplacental complex and measurement of peripheral resistance in the umbilical artery during the second trimester of pregnancy are not very informative. To reduce the negative impact of fetoplacental insufficiency and its timely diagnosis, it is necessary to use radiation methods for examining the motherplacentafetus system. CONCLUSIONS: For timely diagnosis of fetoplacental insufficiency and reduction of its negative impact, it is necessary to use radiation methods of studying the mother-placenta-fetus system.


Author(s):  
Daniela Carnevale ◽  
Lorenzo Carnevale ◽  
Sara Perrotta ◽  
Fabio Pallante ◽  
Agnese Migliaccio ◽  
...  

Chronic exposure of the arterial vasculature to high blood pressure recruits immune cells and contributes to the vascular remodeling, dysfunction, and inflammation observed in hypertension. The mechanisms underlying the interaction between vascular and immune cells remain unknown, hampering the development of effective therapies targeting the vascular-immune interface. Overcoming these limitations requires a reliable, physiologically relevant experimental model of vascular-immune interface. By coculturing a 3-dimensional organ culture vascular system with immune cells of interest, we reproduced ex vivo the vascular-immune interface that occurs in hypertension. In the 3-dimensional vascular-immune interface model, CD8 but not CD4 T cells isolated from hypertensive mice increased the contractile properties of resistance arteries in naive mice, indicating that CD8 lymphocytes directly contribute to enhanced peripheral resistance in hypertension. RNA sequencing of CD8 lymphocytes isolated from prehypertensive mice revealed upregulation of gene pathways involved in chemotaxis, response to IFN-γ and other external stimuli, MAPK cascade activation, and positive regulation of intracellular calcium fluxes, as compared with CD4 T cells. Taken together, these results indicate that hypertensive stimuli program CD8 T cells toward a phenotype with promigratory properties that might account for their ability to enhance myogenic tone of resistance arteries when cocultured in the 3-dimensional system. Here, we demonstrate modeling a 3-dimensional organ culture vascular system that recapitulates the in vivo physiological properties of resistance arteries. This platform holds on a substantial translational potential, not only for hypertension but also for other cardiovascular diseases where vascular-immune interfaces are established and relevant for onset and progression of the disease.


Author(s):  
O.V. Zhbankova ◽  
◽  
O.I. Yushkova ◽  
A.V. Kapustina

Abstract. Introduction. Professional selection of workers in extreme occupations associated with increased danger and responsibility is an important task of labor physiology. The study of psychomotor skills under conditions of acute stress, the assessment of the physiological reactions of the cardiovascular system will determine the professional suitability of candidates for various specialties (technical or intellectual-analytical). Purpose of work. The study of diagnostic methodological approaches to assessing the professional suitability of persons in hazardous professions in psychophysiological professional selection. Materials and methods. Psychophysiological studies included the study of psychomotor skills, psychological testing according to the MMIL and 16 FLO tests, physiological studies of hemodynamic features in candidates with different resistance to stress (calculation of stroke blood volume - SV, MC blood minute volume and peripheral resistance of PS), professional analysis of the labor activity of workers to identify the requirements that hazardous professions place on the body of workers, Research results. In candidates for engineering and technical specialties, the tension of the circulatory system reflected high values of the average dynamic pressure (105.73 ± 1.45 mm Hg), changes in the optimal hyperkinetic type of blood circulation to hypokinetic: 66.7% of those examined with low resistance to stress. In candidates for communicative specialties, a sufficient level of physical activity contributed to the stability of the indicators of the cardiovascular system. Conclusions. Informative indicators have been established for assessing the professional suitability of candidates to perform official tasks in extreme conditions: changes in handwriting signs, peculiarities of psychological status (anxiety, conformism), hemodynamic characteristics


2021 ◽  
Author(s):  
Siobhán M Griffin ◽  
Siobhán Howard

Instructed use of reappraisal to regulate stress in the laboratory is typically associated with a more adaptive cardiovascular response to stress, indexed by either: (i) lower cardiovascular reactivity (CVR; e.g., lower blood pressure); or (ii) a challenge-oriented response profile (i.e., greater cardiac output paired with lower total peripheral resistance). In contrast, instructed use of suppression is associated with exaggerated CVR (e.g., greater heart rate, blood pressure). Despite this, few studies have examined if the habitual use of these strategies are related to cardiovascular responding during stress. The current study examined the relationship between cardiovascular responses to acute stress and individual differences in emotion regulation style: trait reappraisal, suppression, and emotion regulation difficulties. Forty-eight participants (25 women, 23 men) completed a standardised laboratory stress paradigm incorporating a 20-minute acclimatization period, a 10-minute baseline, and two 5-minute speech tasks separated by a 10-minute inter-task rest period. The emotional valence of the speech task was examined as a potential moderating factor; participants spoke about a block of negative-emotion words and a block of neutral-emotion words. Cardiovascular parameters were measured using the Finometer Pro. Greater habitual use of suppression was associated with exaggerated blood pressure responding to both tasks. However, only in response to the negative-emotion task was greater use of reappraisal associated with a challenge-oriented cardiovascular response. The findings suggest that individual differences in emotion regulation translate to differing patterns of CVR to stress, but the emotional valence of the stressor may play a role.


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