Um die anderen Arten von Veröffentlichungen zu diesem Thema anzuzeigen, folgen Sie diesem Link: Hemodynamické parametry.
Zeitschriftenartikel zum Thema „Hemodynamické parametry“
Geben Sie eine Quelle nach APA, MLA, Chicago, Harvard und anderen Zitierweisen an
Machen Sie sich mit Top-50 Zeitschriftenartikel für die Forschung zum Thema "Hemodynamické parametry" bekannt.
Neben jedem Werk im Literaturverzeichnis ist die Option "Zur Bibliographie hinzufügen" verfügbar. Nutzen Sie sie, wird Ihre bibliographische Angabe des gewählten Werkes nach der nötigen Zitierweise (APA, MLA, Harvard, Chicago, Vancouver usw.) automatisch gestaltet.
Sie können auch den vollen Text der wissenschaftlichen Publikation im PDF-Format herunterladen und eine Online-Annotation der Arbeit lesen, wenn die relevanten Parameter in den Metadaten verfügbar sind.
Sehen Sie die Zeitschriftenartikel für verschiedene Spezialgebieten durch und erstellen Sie Ihre Bibliographie auf korrekte Weise.
1
Rzheutskaya, Ryta E. „Characteristics of Hemodynamic Disorders in Patients with Severe Traumatic Brain Injury“. Critical Care Research and Practice 2012 (2012): 1–11. http://dx.doi.org/10.1155/2012/606179.
Der volle Inhalt der QuelleAnnotation:
Purpose. To define specific features of central hemodynamic parameter changes in patients with isolated severe traumatic brain injury (STBI) and in patients with clinically established brain death and to determine the required course of treatment for their correction.Data and Research Methods. A close study of central hemodynamic parameters was undertaken. The study involved 13 patients with isolated STBI (group STBI) and 15 patients with isolated STBI and clinically established brain death (group STBI-BD). The parameters of central hemodynamics were researched applying transpulmonary thermodilution.Results. In the present study, various types of hemodynamic reaction (normodynamic, hyperdynamic, and hypodynamic) were identified in patients with isolated STBI in an acute period of traumatic disease. Hyperdynamic type of blood circulation was not observed in patients with isolated STBI and clinically established brain death. Detected hemodynamic disorders led to the correction of the ongoing therapy under the control of central hemodynamic parameters.Conclusions. Monitoring of parameters of central hemodynamics allows to detect the cause of disorders, to timely carry out the required correction, and to coordinate infusion, inotropic, and vasopressor therapy.
2
Franceschi, Claude. „Definition of the venous hemodynamics parameters and concepts“. Veins and Lymphatics 2, Nr. 4 (15.04.2013): 1. http://dx.doi.org/10.4081/hemodynamics.2013.1.
Der volle Inhalt der Quelle
3
Ogilvie, Leslie M., Brittany A. Edgett, Jason S. Huber, Mathew J. Platt, Hermann J. Eberl, Sohrab Lutchmedial, Keith R. Brunt und Jeremy A. Simpson. „Hemodynamic assessment of diastolic function for experimental models“. American Journal of Physiology-Heart and Circulatory Physiology 318, Nr. 5 (01.05.2020): H1139—H1158. http://dx.doi.org/10.1152/ajpheart.00705.2019.
Der volle Inhalt der QuelleAnnotation:
Traditionally, the evaluation of cardiac function has focused on systolic function; however, there is a growing appreciation for the contribution of diastolic function to overall cardiac health. Given the emerging interest in evaluating diastolic function in all models of heart failure, there is a need for sensitivity, accuracy, and precision in the hemodynamic assessment of diastolic function. Hemodynamics measure cardiac pressures in vivo, offering a direct assessment of diastolic function. In this review, we summarize the underlying principles of diastolic function, dividing diastole into two phases: 1) relaxation and 2) filling. We identify parameters used to comprehensively evaluate diastolic function by hemodynamics, clarify how each parameter is obtained, and consider the advantages and limitations associated with each measure. We provide a summary of the sensitivity of each diastolic parameter to loading conditions. Furthermore, we discuss differences that can occur in the accuracy of diastolic and systolic indices when generated by automated software compared with custom software analysis and the magnitude each parameter is influenced during inspiration with healthy breathing and a mild breathing load, commonly expected in heart failure. Finally, we identify key variables to control (e.g., body temperature, anesthetic, sampling rate) when collecting hemodynamic data. This review provides fundamental knowledge for users to succeed in troubleshooting and guidelines for evaluating diastolic function by hemodynamics in experimental models of heart failure. Listen to this article’s corresponding podcast at https://ajpheart.podbean.com/e/assessment-of-diastolic-function/ .
4
ARYNOV, A. A., N. Z. SHAPATOVA und I. М. SMAGINA. „Diagnostics and treatment of hemodynamic disorders in cancer patients: current trends and own experience“. Oncologia i radiologia Kazakhstana 55, Nr. 1 (31.03.2020): 28–29. http://dx.doi.org/10.52532/2663-4864-2020-1-55-28-29.
Der volle Inhalt der QuelleAnnotation:
Relevance: Hemodynamic disorders occupy a central position among pathological syndromes in patients receiving intensive care. Still, their diagnostics and treatment are sometimes delayed, and hemodynamic parameters and types of blood
circulation are misinterpreted. This adds to the severity of such disorders and increases mortality.
The purpose of the study was to analyze the diagnostics and treatment of hemodynamic disorders in cancer patients.
Results: The applied methods of clinical diagnostics and non-invasive monitoring of hemodynamic parameters correlated
well with invasive monitoring methods and have proven useful in the everyday practice of intensive care.
Conclusion: A combination of methods of clinical diagnosis of hemodynamic disorders and with modern non-invasive
methods of measuring central hemodynamics parameters allows for earlier and more accurate diagnostics and correction of
hemodynamic disorders in the perioperative period in cancer patients.
5
Uedono, Hideki, Akihiro Tsuda, Eiji Ishimura, Shinya Nakatani, Masafumi Kurajoh, Katsuhito Mori, Junji Uchida, Masanori Emoto, Tatsuya Nakatani und Masaaki Inaba. „U-shaped relationship between serum uric acid levels and intrarenal hemodynamic parameters in healthy subjects“. American Journal of Physiology-Renal Physiology 312, Nr. 6 (01.06.2017): F992—F997. http://dx.doi.org/10.1152/ajprenal.00645.2016.
Der volle Inhalt der QuelleAnnotation:
Hyperuricemia has been reported to affect renal hemodynamics. In a recent study, both low and high levels of serum uric acid (SUA) were found to be associated with loss of kidney function. The goal of this study was to evaluate the relationship between SUA levels and intrarenal hemodynamic parameters in healthy subjects, using plasma clearance of para-aminohippurate (CPAH) and inulin (Cin). Renal and glomerular hemodynamics were evaluated by simultaneous measurements of CPAH and Cin in 48 healthy subjects (54.6 ± 13.4 yr). Intrarenal hemodynamic parameters, including efferent and afferent (Ra) arteriolar resistance, were calculated using Gómez’s formulas. Relationships of SUA levels with these intrarenal hemodynamic parameters were examined. In quadratic regression analysis, SUA levels had a significant inverse U-shaped relationship with Cin ( P < 0.0001, R2 = 0.350) and CPAH ( P = 0.0093, R2 = 0.188) and a U-shaped relationship with Ra ( P = 0.0011, R2 = 0.262). In multiple regression analysis with normal (3.5–6.0 mg/dl) and mildly low or high (<3.5 or >6.0 mg/dl) SUA levels entered as dummy variables of zero and one, respectively, mildly low or high SUA levels were significantly and independently associated with Ra (β = 0.230, P = 0.0403) after adjustment for several factors ( R2 = 0.597, P < 0.0001). Both mild hyperuricemia and mild hypouricemia are significantly associated with increased Ra, although weakly. The increase in Ra in subjects with mild hyperuricemia or hypouricemia may be related to renal hemodynamic abnormalities, possibly leading to a decline in renal function.
6
Arynov, A. A., N. Z. Shapatova und I. M. Smagina. „Diagnostics and treatment of hemodynamic disorders in cancer patients: current trends and own experience“. Oncologia i radiologia Kazakhstana 55, Nr. 1 (31.03.2020): 32–34. http://dx.doi.org/10.52532/2521-6414-2020-1-55-32-34.
Der volle Inhalt der QuelleAnnotation:
Relevance: Hemodynamic disorders occupy a central
position among pathological syndromes in patients receiving intensive care. Still, their diagnostics and treatment are
sometimes delayed, and hemodynamic parameters and
types of blood circulation are misinterpreted. This adds to
the severity of such disorders and increases mortality.
The purpose of the study was to analyze the diagnostics and treatment of hemodynamic disorders in cancer
patients.
Results: The applied methods of clinical diagnostics
and non-invasive monitoring of hemodynamic parameters
correlated well with invasive monitoring methods and have
proven useful in the everyday practice of intensive care.
Conclusion: A combination of methods of clinical diagnosis of hemodynamic disorders and with modern non-invasive methods of measuring central hemodynamics parameters allows for earlier and more accurate diagnostics
and correction of hemodynamic disorders in the perioperative period in cancer patients.
7
Blissitt, Patricia A. „Hemodynamic Monitoring in the Care of the Critically Ill Neuroscience Patient“. AACN Advanced Critical Care 17, Nr. 3 (01.07.2006): 327–40. http://dx.doi.org/10.4037/15597768-2006-3010.
Der volle Inhalt der QuelleAnnotation:
Hemodynamic monitoring in the care of the critically ill neuroscience patient provides information that assists the clinician in minimizing secondary neuronal injury. Whereas no technology replaces the critical care nurse’s physical assessment, hemodynamic and neurological monitoring provides additional data beyond what is possible with the clinical examination alone. If neurological technology, such as intracranial pressure monitoring, is not available, hemodynamic monitoring along with the neurological examination provides limited but useful information essential to minimizing secondary neuronal injury. The use of hemodynamic monitoring in critically ill neuroscience patients is best exemplified in the management of cerebral vasospasm after aneurysmal subarachnoid hemorrhage. Although improved outcomes have not been scientifically substantiated, multimodality monitoring of intracranial dynamics and systemic hemodynamics and manipulation of these parameters during hypertensive hypervolemic hemodilution therapy may lessen the incidence of cerebral infarction secondary to vasospasm. Monitoring systemic hemodynamics and intracranial dynamics simultaneously assists in prevention, prompt recognition, and effective treatment of neurological deterioration.
8
Khokonova, Tamara Muratovna, Sofiat Khasenovna Sizhazheva, Zhaneta Huseynovna Sabanchieva, Marina Tembulatovna Nalchikova, Jannet Anvarovna Elmurzayeva, Dzhanneta Magometovna Urusbieva, Inara Aslanovna Khakuasheva und Svetlana Sergeevna Solyanik. „Analysis of hemodynamic parameters and quality of life in patients with chronic kidney disease and arterial hypertension“. Revista de la Universidad del Zulia 12, Nr. 33 (08.05.2021): 274–87. http://dx.doi.org/10.46925//rdluz.33.19.
Der volle Inhalt der QuelleAnnotation:
Purpose. The work is devoted to study the effects of antihypertensive, lipid-lowering and metabolic therapy in office and the average hemodynamic parameters, the parameters of central pressure in the aorta, vascular wall stiffness and quality of life in patients with CKD stage 3 in combination with arterial hypertension of 1-2 degrees, and without it. Materials and methods. Were examined patients with arterial hypertension of 1-2 degrees and CKD stage 3. Measured hemodynamic parameters with the help of a daily BP monitor “BPLab”. The quality of life of patients was assessed by the questionnaire MOS SF36. Results. The greatest changes in the indicators of central hemodynamics and vascular stiffness were noted in the group of patients with comorbidity. Conclusion. The combination of antihypertensive therapy (losartan and diltiazem) with meldonium and rosuvastatin significantly decreases indices of central and peripheral hemodynamics and vascular stiffness. Add meldonium part of therapy significantly improves the quality of life of patients.
9
Darowski, M., G. Ferrari, F. Clemente, M. Guaragno und De Lazzari. „Computer Simulation of Hemodynamic Parameter Changes by Mechanical Ventilation and Biventricular Circulatory Support“. Methods of Information in Medicine 39, Nr. 04/05 (2000): 332–38. http://dx.doi.org/10.1055/s-0038-1634451.
Der volle Inhalt der QuelleAnnotation:
Abstract:When a Bi-Ventricular Assist Device (BVAD) is used in conjunction with mechanical ventilation (MV) of the lungs with positive intrathoracic pressure (Pt), the latter influences hemodynamics. The aim of our study was to assess the simultaneous influence of BVAD and MV on hemodynamics. We assumed ventricular pathological conditions as reduced elastances and increased rest volumes. Peripheral systemic arterial resistance was assumed to have different values. Data were obtained by computer simulation. Trends in main hemodynamic variables were compared with clinical data from literature. Simulation showed that systemic venous, pulmonary arterial and left atrial pressures are very sensitive to Pt (-2 to 5 mmHg).
10
Tang, Hong, Ziyin Dai, Miao Wang, Binbin Guo, Shunyu Wang, Jiabin Wen und Ting Li. „Lumped-Parameter Circuit Platform for Simulating Typical Cases of Pulmonary Hypertensions from Point of Hemodynamics“. Journal of Cardiovascular Translational Research 13, Nr. 5 (13.01.2020): 826–52. http://dx.doi.org/10.1007/s12265-020-09953-y.
Der volle Inhalt der QuelleAnnotation:
Abstract Pulmonary hypertension (PH) presents unusual hemodynamic states characterized by abnormal high blood pressure in pulmonary artery. The objective of this study is to simulate how the hemodynamics develops in typical PH cases without treatment. A lumped-parameter circuit platform of human circulation system is set up to simulate hemodynamic abnormalities of PH in different etiologies and pathogenesis. Four typical cases are considered, which are distal pulmonary artery stenosis, left ventricular diastolic dysfunction, ventricular septal defect, and mitral stenosis. The authors propose regulation laws for chambers and vessels to adapt the abnormal hemodynamic conditions for each PH case. The occurrence and development of each PH case are simulated over time using the lumped-parameter circuit platform. The blood pressure, blood flow, pressure-volume relations for chambers and vessels are numerically calculated for each case of PH progression. The model results could be a quite helpful to understand the hemodynamic mechanism of typical PHs.
11
Wong, Kelvin K. L., Jianhuang Wu, Guiying Liu, Wenhua Huang und Dhanjoo N. Ghista. „Coronary arteries hemodynamics: effect of arterial geometry on hemodynamic parameters causing atherosclerosis“. Medical & Biological Engineering & Computing 58, Nr. 8 (09.06.2020): 1831–43. http://dx.doi.org/10.1007/s11517-020-02185-x.
Der volle Inhalt der Quelle
12
Zheng, Hai, Yunlong Huo, Mark Svendsen und Ghassan S. Kassab. „Effect of blood pressure on vascular hemodynamics in acute tachycardia“. Journal of Applied Physiology 109, Nr. 6 (Dezember 2010): 1619–27. http://dx.doi.org/10.1152/japplphysiol.01356.2009.
Der volle Inhalt der QuelleAnnotation:
Paroxysmal supraventricular tachycardia is accompanied by hypotension, which can affect vascular hemodynamics. Here, we hypothesized that a fall in blood flow as a result of hypotension has a larger effect on hemodynamics in medium-sized peripheral arteries compared with increased pulsatility in rapid pacing. To test this hypothesis, we experimentally and theoretically investigated hemodynamic changes in femoral, carotid, and subclavian arteries at heart rates of 95–170 beats/min after acute pacing. The arterial pressure, blood flow, and other hemodynamic parameters remained statistically unchanged for heart rates ≤135 beats/min. Systemic pressure and flow velocities, however, showed an abrupt decrease, resulting in larger alteration of hemodynamic parameters for heart rates ≥155 beats/min after pacing (initial period) and then recovered close to baseline after several minutes of pacing (recovery period). During the initial period, the pressure dropped from 88 mmHg (baseline) to 44 mmHg, and the flow velocity decreased to about one-third of baseline at heart rate of 170 beats/min. A hemodynamic analysis showed a velocity profile with a near-wall retrograde flow or a fully reversed flow during the initial period, which vanished at the recovery period. It was concluded that the initial fall of blood flow due to pressure drop led to transient flow reversal and negative wall shear stress because this phenomena was not observed at the recovery period. This study underscores the significant effects of hypotension on vascular hemodynamics, which may have relevance to physiology and chronic pathophysiology in paroxysmal supraventricular tachycardia.
13
Hidaka, O., M. Yanagi und K. Takada. „Mental Stress-induced Physiological Changes in the Human Masseter Muscle“. Journal of Dental Research 83, Nr. 3 (März 2004): 227–31. http://dx.doi.org/10.1177/154405910408300308.
Der volle Inhalt der QuelleAnnotation:
The effect of a long mental stress on the hemodynamics of masticatory muscles has not been investigated to date. We hypothesized some hemodynamic and electromyographic changes in jaw-closure muscles related to sympathetic nervous system activity. While healthy adult female volunteers performed a two-hour mental stress task, electromyographic activity of the temporal and masseteric muscles was recorded, and hemodynamic changes of the masseter muscle were measured non-invasively. Autonomic function was assessed by heart rate spectral analysis. Integrated electromyographic activity of the temporalis muscle, but not the masseter muscle, showed an increase that coincided with the increase in sympathetic nervous activity. In the masseter muscle, despite little change in integrated electromyographic activity, notable changes were found in hemodynamic parameters. These results suggest that hemodynamics of jaw muscles is susceptible to mental stress, implying a potential role in the etiology of jaw muscle dysfunction associated with mental stress.
14
Konecny, Filip. „Rodent General Anesthesia Suitable for Measurement of Experimental Invasive Hemodynamics“. European Journal of Biology and Biotechnology 2, Nr. 4 (23.08.2021): 33–43. http://dx.doi.org/10.24018/ejbio.2021.2.4.259.
Der volle Inhalt der QuelleAnnotation:
In cases of experimentally performed invasive rodent cardiovascular measurements, selected general anesthesia for a non-recovery procedure and its proper pain control plays a fundamental role in obtaining good data recordings. Rodent anesthesia is challenging for several reasons including high metabolic rate with elevated possibility of hypothermia and hypoglycemia during the procedure, large body surface area to adjust drug medication and anticipate drug clearance. In this review article, suitable analgesia, and anesthesia to collect rodent hemodynamics is discussed with examples of commonly used methods and anesthetic combinations to assess rodent hemodynamics. In case of injectable anesthesia, hemodynamic parameters should be measured when HR and mean arterial pressure (MAP) becomes stable. If re-injection is necessary, re-evaluation of HR and MAP is crucial for data integrity. Likewise, to safeguard data quality, longitudinal collection of HRs, HR variability, MAP and body temperature should be provided. For this reason, creation of a rodent hemodynamic anesthesia protocol might be necessary. In many cases, to refine surgical anesthetic protocol suitable for hemodynamic study, pilot experiments might be required to find the correct dose, and to probe for adequacy and duration of anesthesia, anticipating technical and procedural problems. Additionally, ensuring repeatability of the hemodynamic exam, selected experimental anesthetics should not be extensively metabolized. If metabolized, the effects on central and peripheral hemodynamics (HR, pre, afterload and contractility) should be well-known and documented.
15
Loomba, Rohit S., Vincent Dorsey, Enrique G. Villarreal und Saul Flores. „The effect of milrinone on hemodynamic and gas exchange parameters in children“. Cardiology in the Young 30, Nr. 1 (17.12.2019): 55–61. http://dx.doi.org/10.1017/s1047951119002865.
Der volle Inhalt der QuelleAnnotation:
AbstractMilrinone is a drug frequently used for hemodynamic support in children during critical illness. Although the hemodynamic changes induced by milrinone in children may appear similar to those of adults, the physiologic contributors of these changes remain vastly unknown. A systematic review was conducted to identify studies characterising the hemodynamic effects of milrinone in children during critical illness for hemodynamic support for various medical conditions. Studies were assessed for quality and those of satisfactory quality with pre- and post-operative hemodynamics for each patient were included in the final analyses. Those not limited to children and those not limited to patients with critical illness were excluded from the final analyses. A total of six studies with 791 patients were included in the final analyses. Milrinone infusion doses ranged from 0.3 to 0.75 mcg/kg/minute with the mean infusion dose being 0.5 mcg/kg/minute. Patients whom received milrinone infusion had greater cardiac output, greater left ventricle shortening fraction, lower right ventricular systolic pressure, and lower serum lactate levels. Systolic blood pressure mean arterial blood pressure and arterial oxygen concentration did not significantly change with administration of milrinone. These results were irrespective of milrinone infusion dose, infusion duration, and study size. Milrinone was found to have several beneficial hemodynamic effects in children during critical illness when used at usual clinical doses.
16
Häfner, H. M., E. Piche und M. Jünger. „The ratio of working pressure to resting pressure under compression stockings: Its significance for the improvement of venous perfusion in the legs“. Phlebologie 30, Nr. 04 (April 2001): 88–93. http://dx.doi.org/10.1055/s-0037-1617300.
Der volle Inhalt der QuelleAnnotation:
Summary Aim: A variety of medical compression products are available for the treatment of chronic venous insufficiency. Aim of this study was to quantify the acute effects of different compression class 2 (CCL2) stockings on venous hemodynamics. We examined the pressure exerted by the stockings as a biophysical parameter and tested for correlations between it and an improvement in venous hemodynamics. Methods: A total of 42 patients with chronic venous insufficiency in stages C1-4 Ep AS, A14, Ap, PR (CEAP classification) took part in the study. Venous hemodynamics were measured by dynamic strain-gauge plethysmography with and without a variety of different CCL2 compression stockings. At the same time, the pressure exerted by the stockings was measured under static conditions (resting pressure) and under dynamic conditions (working pressure). Results: Each of the CCL2 medical compression stockings tested here brought about a different degree of hemodynamic improvement. The amount by which venous refilling time was lengthened varied from one stocking to the next. Hemodynamic improvement was closely correlated with the ratio of working pressure to resting pressure exerted by the stockings (r = 0.90, p <0.001). Conclusion: The degree of hemodynamic improvement attained depended on the elasticity of the compression stocking, i.e. the ratio of maximum working pressure to resting pressure exerted by the stocking.
17
Voitikova, M. V., und R. V. Khursa. „Classification of Hemodynamics Using a Diagnostic Nomogram and Ambulatory Blood Pressure Data“. Nonlinear Phenomena in Complex Systems 23, Nr. 3 (28.10.2020): 291–98. http://dx.doi.org/10.33581/1561-4085-2020-23-3-291-298.
Der volle Inhalt der QuelleAnnotation:
This article provides a detailed overview of the hemodynamic nomogram, a new diagnostic tool in hemodynamics based on the linear regression modeling of ambulatory blood pressure monitoring data (ABPM) and the Support Vector Machine (SVM) classifier. We investigated the classification capability and practical usage of the diagnostic nomogram, as well as cardiovascular phenomena described and limitations of linear modeling.One of the practical applications of the nomogram is the ability to retrace changes in ABPM parameters due to antihypertensive therapy. Misclassifications are explained by nonlinear properties of the hemodynamics of diastolic type.
18
Zhang, Xin, Tamrakar Karuna, Zhi-Qiang Yao, Chuan-Zhi Duan, Xue-Min Wang, Shun-Ting Jiang, Xi-Feng Li et al. „High wall shear stress beyond a certain range in the parent artery could predict the risk of anterior communicating artery aneurysm rupture at follow-up“. Journal of Neurosurgery 131, Nr. 3 (September 2019): 868–75. http://dx.doi.org/10.3171/2018.4.jns173179.
Der volle Inhalt der QuelleAnnotation:
OBJECTIVEAmong clinical and morphological criteria, hemodynamics is the main predictor of aneurysm growth and rupture. This study aimed to identify which hemodynamic parameter in the parent artery could independently predict the rupture of anterior communicating artery (ACoA) aneurysms by using multivariate logistic regression and two-piecewise linear regression models. An additional objective was to look for a more simplified and convenient alternative to the widely used computational fluid dynamics (CFD) techniques to detect wall shear stress (WSS) as a screening tool for predicting the risk of aneurysm rupture during the follow-up of patients who did not undergo embolization or surgery.METHODSOne hundred sixty-two patients harboring ACoA aneurysms (130 ruptured and 32 unruptured) confirmed by 3D digital subtraction angiography at three centers were selected for this study. Morphological and hemodynamic parameters were evaluated for significance with respect to aneurysm rupture. Local hemodynamic parameters were obtained by MR angiography and transcranial color-coded duplex sonography to calculate WSS magnitude. Multivariate logistic regression and a two-piecewise linear regression analysis were performed to identify which hemodynamic parameter independently characterizes the rupture status of ACoA aneurysms.RESULTSUnivariate analysis showed that WSS (p < 0.001), circumferential wall tension (p = 0.005), age (p < 0.001), the angle between the A1 and A2 segments of the anterior cerebral artery (p < 0.001), size ratio (p = 0.023), aneurysm angle (p < 0.001), irregular shape (p = 0.005), and hypertension (grade II) (p = 0.006) were significant parameters. Multivariate analyses showed significant association between WSS in the parent artery and ACoA aneurysm rupture (p = 0.0001). WSS magnitude, evaluated by a two-piecewise linear regression model, was significantly correlated with the rupture of the ACoA aneurysm when the magnitude was higher than 12.3 dyne/cm2 (HR 7.2, 95% CI 1.5–33.6, p = 0.013).CONCLUSIONSWSS in the parent artery may be one of the reliable hemodynamic parameters characterizing the rupture status of ACoA aneurysms when the WSS magnitude is higher than 12.3 dyne/cm2. Analysis showed that with each additional unit of WSS (even with a 1-unit increase of WSS), there was a 6.2-fold increase in the risk of rupture for ACoA aneurysms.
19
Soldozy, Sauson, Pedro Norat, Mazin Elsarrag, Ajay Chatrath, John S. Costello, Jennifer D. Sokolowski, Petr Tvrdik, M. Yashar S. Kalani und Min S. Park. „The biophysical role of hemodynamics in the pathogenesis of cerebral aneurysm formation and rupture“. Neurosurgical Focus 47, Nr. 1 (Juli 2019): E11. http://dx.doi.org/10.3171/2019.4.focus19232.
Der volle Inhalt der QuelleAnnotation:
The pathogenesis of intracranial aneurysms remains complex and multifactorial. While vascular, genetic, and epidemiological factors play a role, nascent aneurysm formation is believed to be induced by hemodynamic forces. Hemodynamic stresses and vascular insults lead to additional aneurysm and vessel remodeling. Advanced imaging techniques allow us to better define the roles of aneurysm and vessel morphology and hemodynamic parameters, such as wall shear stress, oscillatory shear index, and patterns of flow on aneurysm formation, growth, and rupture. While a complete understanding of the interplay between these hemodynamic variables remains elusive, the authors review the efforts that have been made over the past several decades in an attempt to elucidate the physical and biological interactions that govern aneurysm pathophysiology. Furthermore, the current clinical utility of hemodynamics in predicting aneurysm rupture is discussed.
20
Damiano, Robert J., Vincent M. Tutino, Nikhil Paliwal, Tatsat R. Patel, Muhammad Waqas, Elad I. Levy, Jason M. Davies, Adnan H. Siddiqui und Hui Meng. „Aneurysm characteristics, coil packing, and post-coiling hemodynamics affect long-term treatment outcome“. Journal of NeuroInterventional Surgery 12, Nr. 7 (17.12.2019): 706–13. http://dx.doi.org/10.1136/neurintsurg-2019-015422.
Der volle Inhalt der QuelleAnnotation:
BackgroundRecurrence of intracranial aneurysms after endovascular coiling is a serious clinical concern.ObjectiveWe hypothesized that recurrence is associated with aneurysm morphology and flow, as well as the coil intervention and the induced flow modifications.MethodsWe collected 52 primary-coiling aneurysm cases that were either occluded (n=34) or recurrent (n=18) at >1 year follow-up. We created aneurysm models from pre-coiling digital subtraction angiographic images, calculated aneurysm morphology, simulated pre-coiling hemodynamics, modeled coil deployment, and obtained post-coiling hemodynamics for each case. We performed univariable analysis on 26 morphologic, treatment-specific, and hemodynamic parameters to distinguish between recurrent and occluded groups, and multivariable analysis to identify independently significant parameters associated with recurrence. Univariable analysis was also performed on ruptured and unruptured aneurysm subcohorts separately to investigate if they shared specific significant parameters.ResultsRecurrence was associated with pre-coiling aneurysm morphologic and flow parameters including larger size (maximum dimension and volume), larger neck (diameter, area, and neck-to-parent-artery ratio), and higher flow momentum and kinetic energy. Recurrence was also associated with lower coil packing (packing density and uncoiled volume), higher post-treatment flow (velocity, momentum, and kinetic energy), lower post-treatment washout time, and higher post-treatment impingement force at the neck. Multivariable analysis identified two aneurysmal characteristics (neck diameter and pre-coiling flow kinetic energy), one coil packing parameter (uncoiled volume), and one post-treatment hemodynamic parameter (flow momentum) that were independently associated with recurrence. In ruptured aneurysms, recurrence was associated with larger neck (diameter and area), whereas in unruptured aneurysms, recurrence was associated with larger size (maximum dimension and volume). In both subcohorts, recurrence was associated with higher post-coiling flow momentum and kinetic energy.ConclusionRecurrence at >1 year after coil treatment is associated with intrinsic aneurysm characteristics, coiling itself, and flow changes induced by coiling. Larger aneurysm size and neck, less coil packing, and higher intra-aneurysmal flow before and after coiling predict recurrence.
21
Sun, Y., M. Beshara, R. J. Lucariello und S. A. Chiaramida. „A comprehensive model for right-left heart interaction under the influence of pericardium and baroreflex“. American Journal of Physiology-Heart and Circulatory Physiology 272, Nr. 3 (01.03.1997): H1499—H1515. http://dx.doi.org/10.1152/ajpheart.1997.272.3.h1499.
Der volle Inhalt der QuelleAnnotation:
A phenomenological model of the cardiopulmonary circulation is developed with a focus on the interaction between the right heart and the left heart. The model predicts the hemodynamic consequences of changing circulatory parameters in terms of a broad spectrum of pressure and flow waveforms. Hemodynamics are characterized by use of an electrical analog incorporating mechanisms for transseptal pressure coupling, pericardial volume coupling, intrathoracic pressure, and baroreflex control of heart rate. Computer simulations are accomplished by numerically integrating 28 differential equations that contain nonlinear and time-varying coefficients. Validity of the model is supported by its accurate fit to clinical pressure and Doppler echocardiographic recordings. The model characterizes the hemodynamic waveforms for mitral stenosis, mitral regurgitation, left heart failure, right heart failure, cardiac tamponade, pulsus paradoxus, and the Valsalva maneuver. The wave shapes of pulmonary capillary wedge pressure under the above conditions are also accurately represented. Sensitivity analysis reveals that simulated hemodynamics are insensitive to most individual model parameters with the exception of afterload resistance, preload capacitances, intrathoracic pressure, contractility, and pericardial fluid volume. Baseline hemodynamics are minimally affected by transseptal coupling (up to 2%) and significantly affected by pericardial coupling (up to 20%). The model should be useful for quantitative studies of cardiopulmonary dynamics related to the right-left heart interaction under normal and disease conditions.
22
Shilin, D. S., und K. G. Shapovalov. „Hemodynamic Parameters After Prone Positioning of COVID-19 Patients“. General Reanimatology 17, Nr. 3 (03.07.2021): 32–41. http://dx.doi.org/10.15360/1813-9779-2021-3-32-41.
Der volle Inhalt der QuelleAnnotation:
Aim of the study. To examine the effect of prone positioning on hemodynamics in patients with COVID-19.Materials and methods. The study enrolled 84 patients of both sexes with community-acquired multisegmental viral and bacterial pneumonia associated with COVID-19, who were divided into groups according to the type of respiratory support. The tests were performed using the integrated hardware and software system for noninvasive central hemodynamic assessment by volumetric compression oscillometry.Results. We found that the pulse blood pressure velocity decreased from 281 [242.0; 314.0] to 252 [209; 304] mm Hg/s in patients with severe COVID-19 on oxygen support (p=0.005); volume ejection rate decreased from 251 [200; 294] to 226 [186; 260] ml/s (P=0.03); actual/estimated normalized vascular resistance ratio dropped from 0.549 [0.400; 0.700] to 0.450 [0.300; 0.600] (P=0.002), while the arterial wall compliance increased from 1.37 [1.28; 1.67] to 1.45[1.10; 1.60] ml/mm Hg (P=0.009). Prone positioning of patients on noninvasive lung ventilation associated with a reduction of linear blood flow rate from 40.0 [34.0; 42.0] to 42.5 [42.5; 47.25] cm/s (7=0.04) and arterial wall compliance from 1.4 [1.24; 1.50] to 1.32 [1.14; 1.49] ml/mm Hg (7=0.03). Prone positioning of patients on invasive lung ventilation did not result in significant hemodynamic changes.Conclusion. The greatest hemodynamic changes during prone positioning were found in patients on oxygen respiratory support, whereas the least significant alterations were seen in patients on invasive ventilatory support.
23
Jeong, Woowon, und Kyehan Rhee. „Hemodynamics of Cerebral Aneurysms: Computational Analyses of Aneurysm Progress and Treatment“. Computational and Mathematical Methods in Medicine 2012 (2012): 1–11. http://dx.doi.org/10.1155/2012/782801.
Der volle Inhalt der QuelleAnnotation:
The progression of a cerebral aneurysm involves degenerative arterial wall remodeling. Various hemodynamic parameters are suspected to be major mechanical factors related to the genesis and progression of vascular diseases. Flow alterations caused by the insertion of coils and stents for interventional aneurysm treatment may affect the aneurysm embolization process. Therefore, knowledge of hemodynamic parameters may provide physicians with an advanced understanding of aneurysm progression and rupture, as well as the effectiveness of endovascular treatments. Progress in medical imaging and information technology has enabled the prediction of flow fields in the patient-specific blood vessels using computational analysis. In this paper, recent computational hemodynamic studies on cerebral aneurysm initiation, progress, and rupture are reviewed. State-of-the-art computational aneurysmal flow analyses after coiling and stenting are also summarized. We expect the computational analysis of hemodynamics in cerebral aneurysms to provide valuable information for planning and follow-up decisions for treatment.
24
Nikolaeva, I. P., A. S. Kapranova, V. B. Popova, A. N. Lodyagin und T. A. Frolova. „INFLUENCE OF THE DEGREE OF OBESITY AND HIGH-VOLUME LIPOSUCTIONON BODY COMPOSITION, HEMODYNAMIC CHANGES, BLOOD OXYGEN“. HERALD of North-Western State Medical University named after I.I. Mechnikov 6, Nr. 4 (15.12.2014): 32–38. http://dx.doi.org/10.17816/mechnikov20146432-38.
Der volle Inhalt der QuelleAnnotation:
To evaluate the influence of the degree of obesity and high-volume liposuction on body composition, hemodynamic, blood oxygen. The actual values of the cardiac index and stroke index, as well as the calculation of these indicators on a body surface area of the "ideal subject" showed a significant correlation with body mass index, which confirms the impact of obesity on hemodynamic changes, myocardial dysfunction and the development of severe arterial hypoxemia. Analysis of the parameters of liquid sectors body showed insufficient increase in total, extracellular fluid and blood volume by a significant rise of fat and muscle mass. It is believed that the increase in blood volume in obesity is adaptive in nature and occurs in response to expansion of the vascular bed with increasing body weight. After liposuction large volume of significant hemodynamic changes were not obtained. In the late period against reduction in fat mass oxygenizing improved lung function. Carrying a large volume liposuction are not adversely impact on the reserve possibilities myocardial hemodynamics in the long term. Timely diagnosis of adaptive changes in hemodynamics and fluid sectors organism, which can be considered as prognostic risk factors must be considered when choosing the volume lipoaspiration.
25
Miranda, Marcos, Michelle Balarini, Daniella Caixeta und Eliete Bouskela. „Microcirculatory dysfunction in sepsis: pathophysiology, clinical monitoring, and potential therapies“. American Journal of Physiology-Heart and Circulatory Physiology 311, Nr. 1 (01.07.2016): H24—H35. http://dx.doi.org/10.1152/ajpheart.00034.2016.
Der volle Inhalt der QuelleAnnotation:
Abnormal microvascular perfusion, including decreased functional capillary density and increased blood flow heterogeneity, is observed in early stages of the systemic inflammatory response to infection and appears to have prognostic significance in human sepsis. It is known that improvements in systemic hemodynamics are weakly correlated with the correction of microcirculatory parameters, despite an appropriate treatment of macrohemodynamic abnormalities. Furthermore, conventional hemodynamic monitoring systems available in clinical practice fail to detect microcirculatory parameter changes and responses to treatments, as they do not evaluate intrinsic events that occur in the microcirculation. Fortunately, some bedside diagnostic methods and therapeutic options are specifically directed to the assessment and treatment of microcirculatory changes. In the present review we discuss fundamental aspects of septic microcirculatory abnormalities, including pathophysiology, clinical monitoring, and potential therapies.
26
Stroukov, D. V., A. G. Vasilev und Yu S. Alexandrovich. „Quick model of septic shock in rats“. Regional blood circulation and microcirculation 15, Nr. 1 (30.03.2016): 73–77. http://dx.doi.org/10.24884/1682-6655-2016-15-1-73-77.
Der volle Inhalt der QuelleAnnotation:
Modeling septic shock by means of administration of living bacteria is a minimum invasive adequate model for reproduction of this pathologic process, however there is a few data on effectiveness of this model in rats on the basis of direct measurement of hemodynamic parameters. The goal of the study was to elaborate a simple and convenient model of septic shock by intravenous infusion of living bifidobacteria. Indexes of central hemodynamics evaluated by direct method were analyzed in the study as well as endothelial function of blood vessels assessed by measuring concentration of NO, vessels' endothelial growth factor-A and tissue plasminogen activator. Dysfunction of hemostasis was also estimated by measuring fibrinogen level and soluble complexes of fibrin monomer. Intravenous infusion of living bifidobacteria caused development of severe septic shock by 15th minute after administration with valid decrease of all systemic hemodynamics' parameters. Marked hemodynamic disturbancies combined with development of endothelial dysfunction and hemostatic mechanisms' increased activity. The present model is absolutely safe; it can be easily reproduced in a research or training laboratory and it can be used for fundamental research of septic shock, for pre-clinical tests of drugs as well as for educational purposes.
27
Vecherkin, Vladimir А., O. K. Voronova, D. A. Toma und P. V. Koryashkin. „THE “THIRD MODE” OF BLOOD FLOW AND PARAMETERS OF CENTRAL HEMODYNAMICS IN CHILDREN WITH APPENDICULAR PERITONITIS AND DESTRUCTIVE PNEUMONIA“. Russian Journal of Pediatric Surgery 23, Nr. 4 (17.09.2019): 193–95. http://dx.doi.org/10.18821/1560-9510-2019-23-4-193-195.
Der volle Inhalt der QuelleAnnotation:
Introduction. In modern world literature there are no data on changes in the central hemodynamics in children with purulent-septic pathologies. Purpose: to improve diagnostics of cardiovascular disorders in children with appendicular peritonitis and destructive pneumonia using device “Cardiocode”. Material and methods. The trial with “Cardiocode” was conducted in two regional medical centers in Voronezh and Belgorod. Hemodynamic parameters were studied in healthy children (n = 60), in children with destructive pneumonia (n = 83) and in children with appendicular peritonitis (n = 98). Parameters of the central hemodynamics were studied in pre- and postoperative period until recovery. Results. It has been found out that in children with appendicular peritonitis and destructive pneumonia the heart rate exceeds normal limits by 37-58%. The stroke volume in children with appendicular peritonitis did not differ of normal values, while in children with destructive pneumonia it declines by 10-15%. Early diastole was significantly reduced on admission, by 75-85% of normal limits. Reduction of parameters was recorded in the rapid expulsion of left ventricular systole from 80% to 70% of normal limits. In children with destructive pneumonia and appendicular peritonitis, tone of the ascending part of the aorta (Vt.a) was increased as well. conclusion. Apparatus "Cardiocode" is an effective non-invasive tool for early diagnostics and for controlling treatment of hemodynamic disorders in children with appendicular peritonitis and destructive pneumonia.
28
Wang, Haoran, Hitomi Anzai, Youjun Liu, Aike Qiao, Jinsheng Xie und Makoto Ohta. „Hemodynamic-Based Evaluation on Thrombosis Risk of Fusiform Coronary Artery Aneurysms Using Computational Fluid Dynamic Simulation Method“. Complexity 2020 (20.10.2020): 1–11. http://dx.doi.org/10.1155/2020/8507273.
Der volle Inhalt der QuelleAnnotation:
Coronary artery aneurysms (CAAs) have been reported to associate with an increased risk for thrombosis. Distinct to the brain aneurysm, which can cause a rupture, CAA’s threat is more about its potential to induce thrombosis, leading to myocardial infarction. Case reports suggest that thrombosis risk varied with the different CAA diameters and hemodynamics effects (usually wall shear stress (WSS), oscillatory shear index (OSI), and relative residence time (RRT)) may relate to the thrombosis risk. However, currently, due to the rareness of the disease, there is limited knowledge of the hemodynamics effects of CAA. The aim of the study was to estimate the relationship between hemodynamic effects and different diameters of CAAs. Computational fluid dynamics (CFD) provides a noninvasive means of hemodynamic research. Four three-dimensional models were constructed, representing coronary arteries with a normal diameter (1x) and CAAs with diameters two (2x), three (3x), and five times (5x) that of the normal diameter. A lumped parameter model (LPM) which can capture the feature of coronary blood flow supplied the boundary conditions. WSS in the aneurysm decreased 97.7% apparently from 3.51 Pa (1x) to 0.08 Pa (5x). OSI and RRT in the aneurysm were increased apparently by two orders of magnitude from 0.01 (1x) to 0.30 (5x), and from 0.38 Pa−1 (1x) to 51.59 Pa−1 (5x), separately. Changes in the local volume of the CAA resulted in dramatic changes in local hemodynamic parameters. The findings demonstrated that thrombosis risk increased with increasing diameter and was strongly exacerbated at larger diameters of CAA. The 2x model exhibited the lowest thrombosis risk among the models, suggesting the low-damage (medication) treatment may work. High-damage (surgery) treatment may need to be considered when CAA diameter is 3 times or higher. This diameter classification method may be a good example for constructing a more complex hemodynamic-based risk stratification method and could support clinical decision-making in the assessment of CAA.
29
Kulchitskaya, D. B., und S. N. Kolbakhova. „Non-drug methods of treatment of patients with arterial hypertension“. Bulletin of Restorative Medicine 97, Nr. 3 (28.06.2020): 65–68. http://dx.doi.org/10.38025/2078-1962-2020-97-3-65-68.
Der volle Inhalt der QuelleAnnotation:
Worldwide, arterial hypertension (AH) is the most common cardiovascular disease. Despite the fact that today, high efficacy and persistent hypotensive effect of transcerebral pulsed electro- and magnetic therapy in patients with AG has been proven, it seems relevant to develop optimal transcerebral effects for this category of patients. The aim of this study was to select optimal transcerebral effects in patients with mild arterial hypertension, depending on hemodynamic types of central hemodynamics and microcirculation. Methods: The study included 82 patients with MAG from 45 to 79 years and the the duration of the disease from 2 to 11 years.Patients in the first group (40 patients) received MDM mesodial encephalus modulation and in the second group (42 patients) combined magnetotherapy (PeMP and PMP). Results: It was found out that patients with MAG who received MDM had a pronounced hypotensive effect due to improvement of the basic indices of central hemodynamics regardless of the type of blood circulation. As well as MDM causes positive correction of the basic parameters of capillary blood flow, regardless of the initial type of microcirculation. In patients with MAG combined magnetotherapy (PeMP and PMP) causes hypotensive effect, which is accompanied by a favorable restructuring of the basic parameters of central hemodynamics in hyperkinetic type of hemocirculation. Correction of microcirculatory disorders has been established only in patients with spastic type of hemodynamics. Conclusion: On the basis of the conducted studies it is possible to say that MDM and transcerebral combined magnetotherapy contribute to the effectiveness of treatment of patients with hypertension. Sufficiently high efficacy of applied methods allows to approach them in a differentiated way based on clinical and hemodynamic features of hypertension course.
30
Sagaidachnyi, A. A., und A. V. Fomin. „Analysis of time derivative of the temperature response of fingers on the brachial occlusion and its relationship with hemodynamic parameters“. Regional blood circulation and microcirculation 16, Nr. 3 (30.09.2017): 31–40. http://dx.doi.org/10.24884/1682-6655-2017-16-3-31-40.
Der volle Inhalt der QuelleAnnotation:
Objective. The aim of the study was to analyze the time derivative of temperature response of finger phalanges to brachial occlusion and to establish the relationship between the parameters of temperature dynamics and hemodynamic parameters. Materials and methods. To analyze the response to the occlusion, the methods of dynamic thermography and photoplethysmography (PPG) were used. The parameters of the temperature reaction on occlusion in a group of 60 healthy subjects were analyzed. The Shitzer model was used to establish the relationship between temperature dynamics and peripheral hemodynamics. Results. Parameters describing the temperature response of the fingers on occlusion were introduced. It is shown that the time to reach the maximum of the temperature derivative during post-occlusion corresponds to the maximum of the volumetric blood flow. A coefficient of symmetry is proposed that characterizes the curve of the hemodynamic response of the extremity vessels to a sharp restoration of blood flow after removal of the occlusion. The parameters of temperature dynamics paralleled to the changes in hemodynamic parameters. Conclusions. To compare the results of temperature measurements and results of optical methods of blood flow estimation it is advisable to use not the temperature signal but its first derivative. The use of temperature parameters, expressed in degrees, creates the conditions for the development of a quantitative approach to the description of the hemodynamic response to occlusion. The results of the study contribute to the development of noninvasive methods of diagnosing endothelial dysfunction as a harbinger of atherosclerosis.
31
Smolyakov, Yuri N., Boris I. Kuznik, Svetlana A. Kalashnikova, Nikolay A. Nolfin, Ekaterina V. Fedorenko und Mankhar Mikhailovich Mikhahanov. „Adaptation reactions of hemodynamic systems on artificially modulated stress in healthy individuals“. I.P. Pavlov Russian Medical Biological Herald 27, Nr. 4 (11.01.2020): 443–50. http://dx.doi.org/10.23888/pavlovj2019274443-450.
Der volle Inhalt der QuelleAnnotation:
Aim. To study the influence of artificially created stress on hemodynamic parameters of peripheral microcirculation and variability of the heart rhythm in somatically healthy young individuals.
Materials and Methods. In the study 30 individuals were involved (of them 16 men) with the mean age 18.21.1 years. An artificial stress was created using Stroop method. Assessment of characteristics of hemodynamics of microcirculation (HM) was performed by the method of dynamic scattering of light from erythrocytes. The signal was integrated in the form of three hemodynamic indexes: HI (Hemodynamic Indexes). Low frequency index (HI1) was determined by a slow interlayer interaction, high frequency area (HI3) characterized fast shearing of layers. HI2 took intermediate position (precapillary and capillary blood flow). Variability of cardiointervals isolated from pulse component, was assessed by method of variation pulsometry (Heart Rate Variability, HRV).
Results. In the course of study, increase in the heart rate (HR) in the stage of testing was observed that confirms a high extent of stress load. In hemodynamics, redistribution of blood flow was noted toward slow shear velocities (near-wall blood flow). After cessation of stress load, hemodynamic parameters declined and returned to previous values. Parameters characterizing variability of rhythm LF (sympathetic component), HF (vagal activity), CVI (non-linear parasympathetic index) showed a tendency to growth; here, LF/HF ratio did not change.
Conclusion. In result of the carried out study it was possible to formulate a multifactor picture of variation of parameters of microcirculation and of autonomic regulation of cardiac rhythm specific of reactions of adaptation to induced stress. The quantitative criteria of the obtained shears may be integrated into stress indexes to be used in clinical practice. A portable mDLS sensor may be supplemented with specific assessment criteria and used for monitoring of adaptive reactions induced by stressful situations, and for taking early diagnostic and prognostic decisions in the clinical practice, and for self-control of a patient.
32
Shao, Xuebo, Weidong Tang, Lianglong Yu, Qi Chen, Lijun Zhu und Yanyan He. „Adoption of Ultrasonography in Hemodynamic Diagnosis and Monitoring of Severe Respiratory Diseases“. Journal of Medical Imaging and Health Informatics 10, Nr. 9 (01.08.2020): 2073–78. http://dx.doi.org/10.1166/jmihi.2020.3141.
Der volle Inhalt der QuelleAnnotation:
To enhance the clinical diagnosis rate of acute respiratory distress syndrome (ARDS) and provide a reliable basis for follow-up treatment, in this research, the hemodynamic indexes of patients with severe respiratory diseases are monitored by ultrasonic imaging. A total of 64 patients with ARDS in the department of respiratory medicine of XXX hospital from June 2018 to December 2018 are listed as study subjects (including 45 males and 19 females), and are divided into control group (CG) and experimental group (EG) in random. In the CG, central venous pressure is used to detect the patients, while in the EP, ultrasonic imaging is used to detect the patients, and the ultrasonic image is denoised by wavelet transform. Respiratory parameters (respiratory rate, oxygenation index, and positive end-expiratory pressure ventilation) and hemodynamic parameters (heart rate, mean arterial pressure, pulmonary static compliance, and airway plateau pressure) are compared on the first and 10th day of admission. The fluid volume of the two groups of patients was managed according to the hemodynamic parameters. After three months, the prognosis (duration of ICU treatment, duration of mechanical ventilation, incidence of heart failure and mortality) of the patients in both groups were calculated. The results show that wavelet transform can effectively reduce the noise of ultrasonic images, so as to obtain real and reliable data. Compared with the first day of admission, respiratory parameters and hemodynamics of the patient change significantly after 10 days (P < 0.05). The average daily fluid intake in the EP is significantly lower than that in the CG (P < 0.05). The duration of treatment in ICU and mechanical ventilation in the EG is significantly lower than that in the CG (P < 0.05), which indicates that ultrasonic imaging can detect and diagnose the hemodynamics of patients, thus providing reliable guidance for patients’ fluid management and avoiding patients’ cardiac failure induced by fluid overload. This provides an experimental scheme for hemodynamic monitoring of patients with severe respiratory system.
33
Skodvin, Torbjørn Øygard, Øyvind Evju, Christian A. Helland und Jørgen Gjernes Isaksen. „Rupture prediction of intracranial aneurysms: a nationwide matched case-control study of hemodynamics at the time of diagnosis“. Journal of Neurosurgery 129, Nr. 4 (Oktober 2018): 854–60. http://dx.doi.org/10.3171/2017.5.jns17195.
Der volle Inhalt der QuelleAnnotation:
OBJECTIVEHemodynamic rupture predictors in intracranial aneurysms (IAs) must be investigated in prerupture aneurysms, because rupture might significantly alter aneurysm hemodynamics. Both clinical and aneurysmal factors influence hemodynamics, possibly confounding results in unmatched patient materials. The authors aimed to identify hemodynamic variables at the time of diagnosis that could be associated with IA rupture.METHODSA nationwide matched case-control study of IA hemodynamics at the time of diagnosis was performed. Twelve IAs that later ruptured were matched 1:2 with control aneurysms that remained unruptured during a median follow-up time of 4.5 years (interquartile range 3.7–8.2 years). Cases and controls were matched by aneurysm location and size, and patient sex and age. Hemodynamic parameters were obtained from computational fluid dynamics simulations.RESULTSThe low shear area (LSA) was significantly higher in cases than in controls in univariate analysis (p = 0.041). Minimum logarithmic wall shear stress, averaged logarithmic wall shear stress, pressure loss coefficient, and inflow concentration index showed a tendency to be associated with later rupture (p = 0.09, 0.14, 0.15, and 0.18, respectively). The LSA remained statistically significant in multivariable analysis (p = 0.030).CONCLUSIONSHemodynamics at the time of diagnosis are different in aneurysms that later rupture than in those that remain unruptured. Increased LSA might be an early predictor of rupture.
34
Figliuzzi, M. M., S. Sestito, D. Pacifico, L. Parentela und Carlo Rengo. „Relationship between Macrovascular and Microvascular Hemodynamics Assessed by Spectrophotometry in Periodontal Diseases“. International Journal of Dentistry 2021 (03.06.2021): 1–4. http://dx.doi.org/10.1155/2021/9925198.
Der volle Inhalt der QuelleAnnotation:
Objective. The aim of this study is to identify a possible link between macrovascular hemodynamic status and microvascular hemodynamic indices in patients with periodontal disease. Methods and Materials. Seventeen adult patients are recruited on a voluntary basis at the Dentistry Department of the “Mater Domini” University of Catanzaro, with sampling that determines the lipid profile, blood glucose, inflammatory mediators, blood plasma viscosity: anamnesis, blood pressure measurement, and detection of anthropometric parameters: eco-Doppler of the carotid arteries and brachial arteries with noninvasive measurements of hemodynamics and evaluation of inflammation and periodontal circulation with a noninvasive spectroscopic technique. The subjects underwent a dental inspection with periodontal proves. The different indices of periodontal disease were evaluated. Results. The sites with high probing depth differ from the healthy ones, showing low oxygen saturation and a notable increase in tissue edema, but no correlation between macro- and microvascular values was found. Conclusion. Periodontal probing and spectroscopic examination showed the correlation between low oxygen saturation levels and tissue edema values with probing depth; however, no correlation between macrovascular hemodynamic status and microvascular hemodynamics indices was found probably given the heterogeneity of the population under consideration, the low number of data gathered, and the small sample size.
35
Paliwal, Nikhil, Prakhar Jaiswal, Vincent M. Tutino, Hussain Shallwani, Jason M. Davies, Adnan H. Siddiqui, Rahul Rai und Hui Meng. „Outcome prediction of intracranial aneurysm treatment by flow diverters using machine learning“. Neurosurgical Focus 45, Nr. 5 (November 2018): E7. http://dx.doi.org/10.3171/2018.8.focus18332.
Der volle Inhalt der QuelleAnnotation:
OBJECTIVEFlow diverters (FDs) are designed to occlude intracranial aneurysms (IAs) while preserving flow to essential arteries. Incomplete occlusion exposes patients to risks of thromboembolic complications and rupture. A priori assessment of FD treatment outcome could enable treatment optimization leading to better outcomes. To that end, the authors applied image-based computational analysis to clinically FD-treated aneurysms to extract information regarding morphology, pre- and post-treatment hemodynamics, and FD-device characteristics and then used these parameters to train machine learning algorithms to predict 6-month clinical outcomes after FD treatment.METHODSData were retrospectively collected for 84 FD-treated sidewall aneurysms in 80 patients. Based on 6-month angiographic outcomes, IAs were classified as occluded (n = 63) or residual (incomplete occlusion, n = 21). For each case, the authors modeled FD deployment using a fast virtual stenting algorithm and hemodynamics using image-based computational fluid dynamics. Sixteen morphological, hemodynamic, and FD-based parameters were calculated for each aneurysm. Aneurysms were randomly assigned to a training or testing cohort in approximately a 3:1 ratio. The Student t-test and Mann-Whitney U-test were performed on data from the training cohort to identify significant parameters distinguishing the occluded from residual groups. Predictive models were trained using 4 types of supervised machine learning algorithms: logistic regression (LR), support vector machine (SVM; linear and Gaussian kernels), K-nearest neighbor, and neural network (NN). In the testing cohort, the authors compared outcome prediction by each model trained using all parameters versus only the significant parameters.RESULTSThe training cohort (n = 64) consisted of 48 occluded and 16 residual aneurysms and the testing cohort (n = 20) consisted of 15 occluded and 5 residual aneurysms. Significance tests yielded 2 morphological (ostium ratio and neck ratio) and 3 hemodynamic (pre-treatment inflow rate, post-treatment inflow rate, and post-treatment aneurysm averaged velocity) discriminants between the occluded (good-outcome) and the residual (bad-outcome) group. In both training and testing, all the models trained using all 16 parameters performed better than all the models trained using only the 5 significant parameters. Among the all-parameter models, NN (AUC = 0.967) performed the best during training, followed by LR and linear SVM (AUC = 0.941 and 0.914, respectively). During testing, NN and Gaussian-SVM models had the highest accuracy (90%) in predicting occlusion outcome.CONCLUSIONSNN and Gaussian-SVM models incorporating all 16 morphological, hemodynamic, and FD-related parameters predicted 6-month occlusion outcome of FD treatment with 90% accuracy. More robust models using the computational workflow and machine learning could be trained on larger patient databases toward clinical use in patient-specific treatment planning and optimization.
36
Kopka, Lech, und Ewelina Zawadzka-Bartczak. „IMPACT OF TRAINING ON HEMODYNAMIC PARAMETERS MEASURED DURING ANTI-G MANEUVERS“. Polish Journal of Aviation Medicine and Psychology 19, Nr. 1 (02.01.2013): 13–20. http://dx.doi.org/10.13174/pjamp.19.01.2013.2.
Der volle Inhalt der Quelle
37
Shuxratovich, Joniev Sanjar, Shukur Pardaev Kuylievich, Akramov Bahodir Raxmonovich und Hushvakov Ulmas Oftedal Ugli. „Monitoring And Evaluation Of Hemodynamic Parameters During Anesthesia In Endocrine Surgery“. American Journal of Medical Sciences and Pharmaceutical Research 02, Nr. 12 (28.12.2020): 40–46. http://dx.doi.org/10.37547/tajmspr/volume02issue12-08.
Der volle Inhalt der QuelleAnnotation:
The article presents the results of preoperative preparation, anesthesia and surgical treatment of patients operated on for non-toxic nodular goiter. A new approach to preoperative preparation for thyroid surgery is described. The effectiveness in the preoperative period of using the modified method of preoperative preparation using sibazon and droperidol and anesthesia with the use of ketamine and the advantages of this method compared with other methods of general anesthesia are shown.
38
Yambe, T., S. Nanka, S. Naganuma, S. Kobayashi, H. Akiho, Y. Kakinuma, N. Ohsawa et al. „Can the Artificial Heart Make the Circulation Become Fractal?“ International Journal of Artificial Organs 18, Nr. 4 (April 1995): 190–96. http://dx.doi.org/10.1177/039139889501800403.
Der volle Inhalt der QuelleAnnotation:
In order to analyze the hemodynamic parameters in prosthetic circulation as an entity and not as decomposed parts, non linear mathematical analyzing techniques, including the fractal dimension analyzing theory, were utilized. Two pneumatically actuated ventricular assist devices were implanted, as biventricular bypasses (BVB), in chronic animal experiments, using four healthy adult goats. For the comparison between the natural and prosthetic circulation in the same animals, the BVB type complete prosthetic circulation model with ventricular fibrillation, was adopted. All hemodynamic parameters with natural and prosthetic circulation were recorded under awake conditions, and calculated with a personal computer system. Using the non-linear mathematical technique, the arterial blood pressure waveform was embedded into the return map as the beat-to-beat time series data and fractal dimension analysis were performed to analyze the reconstructed attractor. By the use of the Box counting method, fractal dimension analysis of the hemodynamics was performed. Return map of the hemodynamics during natural and artificial circulation showed fractal characteristics, and fractal dimension analysis of the arterial blood pressure revealed the fact that lower dimensional fractal dynamics were evident during prosthetic circulation. Fractal time series data is suggested to have robustness and error resistance, thus our results suggest that the circulatory regulatory system with an artificial heart may have these desired characteristics.
39
Mahrous, Samar A., Nor Azwadi Che Sidik und Khalid M. Saqr. „Numerical study on the energy cascade of pulsatile Newtonian and power-law flow models in an ICA bifurcation“. PLOS ONE 16, Nr. 1 (25.01.2021): e0245775. http://dx.doi.org/10.1371/journal.pone.0245775.
Der volle Inhalt der QuelleAnnotation:
The complex physics and biology underlying intracranial hemodynamics are yet to be fully revealed. A fully resolved direct numerical simulation (DNS) study has been performed to identify the intrinsic flow dynamics in an idealized carotid bifurcation model. To shed the light on the significance of considering blood shear-thinning properties, the power-law model is compared to the commonly used Newtonian viscosity hypothesis. We scrutinize the kinetic energy cascade (KEC) rates in the Fourier domain and the vortex structure of both fluid models and examine the impact of the power-law viscosity model. The flow intrinsically contains coherent structures which has frequencies corresponding to the boundary frequency, which could be associated with the regulation of endothelial cells. From the proposed comparative study, it is found that KEC rates and the vortex-identification are significantly influenced by the shear-thinning blood properties. Conclusively, from the obtained results, it is found that neglecting the non-Newtonian behavior could lead to underestimation of the hemodynamic parameters at low Reynolds number and overestimation of the hemodynamic parameters by increasing the Reynolds number. In addition, we provide physical insight and discussion onto the hemodynamics associated with endothelial dysfunction which plays significant role in the pathogenesis of intracranial aneurysms.
40
Popović, Zoran B., Umesh N. Khot, Gian M. Novaro, Fernando Casas, Neil L. Greenberg, Mario J. Garcia, Gary S. Francis und James D. Thomas. „Effects of sodium nitroprusside in aortic stenosis associated with severe heart failure: pressure-volume loop analysis using a numerical model“. American Journal of Physiology-Heart and Circulatory Physiology 288, Nr. 1 (Januar 2005): H416—H423. http://dx.doi.org/10.1152/ajpheart.00615.2004.
Der volle Inhalt der QuelleAnnotation:
In the recently published clinical study [Use of Nitroprusside in Left Ventricular Dysfunction and Obstructive Aortic Valve Disease (UNLOAD)], sodium nitroprusside (SNP) improved cardiac function in patients with severe aortic stenosis (AS) and left ventricular (LV) systolic dysfunction. We explored the possible mechanisms of these findings using a series of numerical simulations. A closed-loop lumped parameters model that consists of 24 differential equations relating pressure and flow throughout the circulation was used to analyze the effects of varying hemodynamic conditions in AS. Hemodynamic data from UNLOAD study subjects were used to construct the initial simulation. Systemic vascular resistance (SVR), heart rate, and aortic valve area were directly entered into the model while end-systolic and end-diastolic pressure-volume (P-V) relationships were adjusted using previously published data to match modeled and observed end-systolic and end-diastolic pressures and volumes. Initial simulation of SNP treatment by a reduction of SVR was not adequate. To obtain realistic model hemodynamics that reliably reproduce SNP treatment effects, we performed a series of simulations while simultaneously changing end-systolic elastance ( Ees), end-systolic volume at zero pressure (V0), and diastolic P-V shift. Our data indicate that either an Ees increase or V0 decrease is necessary to obtain realistic model hemodynamics. In five patients, we corroborated our findings by using the model to duplicate individual P-V loops obtained before and during SNP treatment. In conclusion, using a numerical model, we identified ventricular function parameters that are responsible for improved hemodynamics during SNP infusion in AS with LV dysfunction.
41
Hoi, Yiemeng, Hui Meng, Scott H. Woodward, Bernard R. Bendok, Ricardo A. Hanel, Lee R. Guterman und L. Nelson Hopkins. „Effects of arterial geometry on aneurysm growth: three-dimensional computational fluid dynamics study“. Journal of Neurosurgery 101, Nr. 4 (Oktober 2004): 676–81. http://dx.doi.org/10.3171/jns.2004.101.4.0676.
Der volle Inhalt der QuelleAnnotation:
Object. Few researchers have quantified the role of arterial geometry in the pathogenesis of saccular cerebral aneurysms. The authors investigated the effects of parent artery geometry on aneurysm hemodynamics and assessed the implications relative to aneurysm growth and treatment effectiveness. Methods. The hemodynamics of three-dimensional saccular aneurysms arising from the lateral wall of arteries with varying arterial curves (starting with a straight vessel model) and neck sizes were studied using a computational fluid dynamics analysis. The effects of these geometric parameters on hemodynamic parameters, including flow velocity, aneurysm wall shear stress (WSS), and area of elevated WSS during the cardiac cycle (time-dependent impact zone), were quantified. Unlike simulations involving aneurysms located on straight arteries, blood flow inertia (centrifugal effects) rather than viscous diffusion was the predominant force driving blood into aneurysm sacs on curved arteries. As the degree of arterial curvature increased, flow impingement on the distal side of the neck intensified, leading to elevations in the WSS and enlargement of the impact zone at the distal side of the aneurysm neck. Conclusions. Based on these simulations the authors postulate that lateral saccular aneurysms located on more curved arteries are subjected to higher hemodynamic stresses. Saccular aneurysms with wider necks have larger impact zones. The large impact zone at the distal side of the aneurysm neck correlates well with other findings, implicating this zone as the most likely site of aneurysm growth or regrowth of treated lesions. To protect against high hemodynamic stresses, protection of the distal side of the aneurysm neck from flow impingement is critical.
42
Mitrasinovic, Anka, Jovo Kolar, Sandra Radak, Dragoslav Nenezic, Ivana Kupresanin, Nikola Aleksic, Srdjan Babic, Slobodan Tanaskovic, Dejan Mitrasinovic und Djordje Radak. „Ultrasonografic monitoring of hemodynamic parameters in symptomatic and asymptomatic patients with high-grade carotid stenosis prior and following carotid endarterectomy“. Vojnosanitetski pregled 69, Nr. 5 (2012): 399–404. http://dx.doi.org/10.2298/vsp1205399m.
Der volle Inhalt der QuelleAnnotation:
Background/Aim. Doppler ultrasonography is now a reliable diagnostic tool for noninvasive examination of the morphology and hemodynamic parameters of extracranial segments of blood vessels that participate in the brain vascularisation. This diagnostic modality in recent years become the only diagnostic tool prior to surgery. The aim of the study was to determine hemodynamic status in symptomatic and asymtomatic patients with severe carotid stenosis prior to and after carotid endarterectomy (CEA). Methods. A total of 124 symptomatic and 94 asymptomatic patients who had underwent CEA at the Clinic for Cardiovasculare Disease ?Dedinje? in Belgrade were included in this study. Doppler ultrasonography examinations were performed one day before CEA and seven days after it. The peak systolic velocity (PSV), end-dyastolic velocity (EDV), time-averaged maximum blood flow velocity (MV), resistance index (RI) and the blood flow volume (BFV) of the ipsilateral and the contralateral internal carotid artery (ICA) were measured. Results. Diabetes was the only risk factor found significantly more frequent in symptomatic patients. There were significantly more occluded contralateral ICAs in the group of symptomatic patients. There was a significant increase in PSV, EDV, MV and BFV of the ipsilateral ICA after CEA and a significant decrease in PSV, EDV, MV and BFV of the contralateral ICA after CEA. RI is the only hemodynamic parameter without significant changes after CEA in both groups of patients. Comparing the values of hemodynamic parameters after CEA between the group of symptomatic and the group of asymptomatic patients no significant differences were found. Conclusion. The occlusion of the contralateral ICA is an important factor differentiating between symptomatic and asymptomatic patients with severe carotid stenosis. Successful surgery provides good recovery of cerebral hemodynamics in both symtomatic and asymptomatic patients.
43
Shpak, L. V., und E. S. Galoshina. „BENEFITS OF VOLUMETRIC COMPRESSION OSCILLOMETRY FOR THE ASSESSMENT OF HEMODYNAMIC PARAMETERS IN PATIENTS WITH ARTERIAL HYPERTENSION“. Cardiovascular Therapy and Prevention 12, Nr. 2 (20.04.2013): 10–17. http://dx.doi.org/10.15829/1728-8800-2013-2-10-17.
Der volle Inhalt der QuelleAnnotation:
Aim. To compare the parameters of central and peripheral hemodynamics in healthy people and patients with Stage 1–3 arterial hypertension (AH).Material and methods. In total, 105 individuals were examined. The control group (CG) included 50 healthy people (25 women and 25 men; mean age 27,8±0,8 years) with optimal and normal levels of blood pressure (BP) (mean levels 118,5±1,6/71,82±1,2 mm Hg). The main group (MG) included 55 patients (41 women and 14 men; mean age 62,9±1,6 years) with systolo-diastolic AH: Stage 1 in 25 (mean BP levels 146,1±0,9/84,9±1,6 mm Hg), Stage 2 in 20 (164,4±1,8/95±2,1 mm Hg), and Stage 3 in 10 (189,6±10,6/92,6±6,3 mm Hg). The method of volumetric compression oscillometry (VCO) was used to assess a wide range of myocardial and hemodynamic parameters.Results. In AH patients, all AH phenotypes, vascular and cardiac parameters were increasing, with a simultaneous reduction in vascular wall distensibility, in parallel with the AH progression from Stage 1 to Stage 3. This indicated an increase in myocardial contractility, tone strain of arterial wall, and peripheral vascular resistance. From Stage 1 to Stage 3, the prevalence of hyper- and eukinetic cardiac hemodynamic types was decreasing, while the prevalence of mixed and hypokinetic types was increasing. The mixed hemodynamic type (a combination of hyper-, eu-, and particularly hypokinetic type characteristics) was considered as an incompletely developed disadaptive hypokinetic type.Conclusion. The VCO method is an effective, non-invasive way to simultaneously assess the status of multiple hemodynamic parameters in both healthy people and AH patients. A specific benefit of this method is the registration of lateral BP levels and identification of mixed (additional) hemodynamic type.
44
Arandjelovic-Minic, Gordana. „Sensitivity of hemodynamic parameters obtained by conventional duplex scanner in the evaluation of extracranial carotid disease severity“. Vojnosanitetski pregled 60, Nr. 4 (2003): 435–42. http://dx.doi.org/10.2298/vsp0304435a.
Der volle Inhalt der QuelleAnnotation:
Progresson of extracranial carotid disease is considered to be significant independent predictor in the evaluation of individual cerebrovascular prognosis. Doppler ultrasonography is a useful screening method in the diagnosis and evaluation of extracranial carotid disease. The aim of this study was to establish the most sensitive hemodynamic parameter of Doppler-ultrasonographic spectral analysis in clinical evaluation of extracranial carotid disease. Investigation included 90 patients (of both sexes) in hospital and outpatient clinic care. Spectral analysis (M-scanning technique) was used for the evaluation of hemodynamic status of carotid sinus, including the following parameters: Pourcelot (A-D/A), Gosling (A/B) and Mol (A/D) resistance parameters. After statistical processing the results of the research affirmed hemodynamic parameters' values and correlation between Pourcelot hemodynamic parameter and the degree of carotid stenosis ?=0,59 for all patients, and ?=0,58 for patients with pathological values. Correlation between Mol parameter and the degree of carotid stenosis was ?=0,50 for all patients, and ?=0,57 for patients with pathological values. Gosling parameter was not significantly different in mean value and was present in all three groups. Functional relationship between the degree of carotid stenosis and each of hemodynamic parameters was established. It was concluded that Pourcelot and Mol parameters were significant indicators of asimptomatic carotid disease, but Pourcelot parameter was considered as a more sensitive indicator in the evaluation of extracranial carotid disease.
45
Burleson, Arrmelle C., und Vincent T. Turitto. „Identification of Quantifiable Hemodynamic Factors in the Assessment of Cerebral Aneurysm Behavior On behalf of the Subcommittee on Biorheology of the Scientific and Standardization Committee of the ISTH“. Thrombosis and Haemostasis 76, Nr. 01 (1996): 118–23. http://dx.doi.org/10.1055/s-0038-1650533.
Der volle Inhalt der QuelleAnnotation:
SummaryPrevious experimental and theoretical studies on the hemodynamics of saccular intracranial aneurysms have provided evidence that aneurysms tend to grow, thrombose and rupture when (1) wall shear stress and mural tension are increased compared to normal values, and (2) flow deviates from a laminar unidirectional pattern (for example flow recirculation). Aneurysm wall shear stress, however, is the only hemodynamic factor which has received special attention in terms of estimation. Additional flow-related parameters exist which could potentially bring increased insight into mechanisms for cerebral aneurysm behavior; they could also help categorize the severity of such malformations and design effective intravascular treatment techniques. The purpose of this paper is thus to present an overview of such hemodynamic factors that could assist in determining the geometries which present the greatest risks to patients. These parameters include (1) hemodynamic shear stress, (2) pressure and related stresses, (3) impingement force on the aneurysm wall, (4) inflow rate into the aneurysm, and (5) residence time of blood within the aneurysmal sac. In addition, these factors can also be currently estimated in an in vitro setting.
46
Kolenko, О. V., Е. L. Sorokin und А. А. Fil. „Features of chorioretinal hemodynamics against the background of correction of endothelial dysfunction in women after preeclampsia“. Modern technologies in ophtalmology, Nr. 3 (15.07.2021): 325–29. http://dx.doi.org/10.25276/2312-4911-2021-3-325-329.
Der volle Inhalt der QuelleAnnotation:
Purpose. To assess the clinical efficacy of drug correction of endothelial dysfunction in women at risk using the study of chorioretinal hemodynamic parameters. Material and methods. Using the prediction algorithm developed by us, 60 women were selected at risk of developing vascular retinal pathology. All women were divided into two subgroups. 1st group – 30 patients who underwent courses of drug correction of endothelial dysfunction; 2nd group included 30 women who did not receive courses of prophylactic treatment. The control group was represented by 30 women who underwent physiological pregnancy. The entire population of women underwent a study of the parameters of chorioretinal hemodynamics. Results. By the end of the follow-up period (3–4.5 years) in the 1st group there was a statistically significant improvement in the parameters of chorioretinal hemodynamics in comparison with both the 2nd group in the period 3 years after childbirth, and with the indicators of the 1st group after 6–8 months after childbirth. Conclusion. It can be argued that in the group of women who underwent long-term drug correction of endothelial dysfunction, there was a statistically significant improvement in a number of indicators of chorioretinal hemodynamics compared with women who did not receive prophylactic treatment (p<0.01). Key words: chorioretinal hemodynamics, macular blood flow, linear blood flow velocity, preeclampsia, endothelial dysfunction, drug correction of endothelial dysfunction.
47
Nguyen, Phuc H., Sarah F. Coquis-Knezek, Mohammad W. Mohiuddin, Egemen Tuzun und Christopher M. Quick. „The complex distribution of arterial system mechanical properties, pulsatile hemodynamics, and vascular stresses emerges from three simple adaptive rules“. American Journal of Physiology-Heart and Circulatory Physiology 308, Nr. 5 (01.03.2015): H407—H415. http://dx.doi.org/10.1152/ajpheart.00537.2014.
Der volle Inhalt der QuelleAnnotation:
Arterial mechanical properties, pulsatile hemodynamic variables, and mechanical vascular stresses vary significantly throughout the systemic arterial system. Although the fundamental principles governing pulsatile hemodynamics in elastic arteries are widely accepted, a set of rules governing stress-induced adaptation of mechanical properties can only be indirectly inferred from experimental studies. Previously reported mathematical models have assumed mechanical properties adapt to achieve an assumed target stress “set point.” Simultaneous prediction of the mechanical properties, hemodynamics, and stresses, however, requires that equilibrium stresses are not assumed a priori. Therefore, the purpose of this work was to use a “balance point” approach to identify the simplest set of universal adaptation rules that simultaneously predict observed mechanical properties, hemodynamics, and stresses throughout the human systemic arterial system. First, we employed a classical systemic arterial system model with 121 arterial segments and removed all parameter values except vessel lengths and peripheral resistances. We then assumed vessel radii increase with endothelial shear stress, wall thicknesses increase with circumferential wall stress, and material stiffnesses decrease with circumferential wall stress. Parameters characterizing adaptive responses were assumed to be identical in all arterial segments. Iteratively predicting local mechanical properties, hemodynamics, and stresses reproduced five trends observed when traversing away from the aortic root towards the periphery: decrease in lumen radii, wall thicknesses, and pulsatile flows and increase in wall stiffnesses and pulsatile pressures. The extraordinary complexity of the systemic arterial system can thus arise from independent adaptation of vessels to local stresses characterized by three simple adaptive rules.
48
Culver, M. N., A. A. Flatt und G. J. Grosicki. „0137 Self-Reported Sleep Quality is Associated with Central Hemodynamics in Healthy Individuals“. Sleep 43, Supplement_1 (April 2020): A54. http://dx.doi.org/10.1093/sleep/zsaa056.135.
Der volle Inhalt der QuelleAnnotation:
Abstract Introduction Insufficient sleep is associated with arterial stiffness and elevated cardiovascular disease risk. Central hemodynamics are influenced by arterial stiffness, yet independently predict cardiovascular risk. Relationships between sleep characteristics and central hemodynamic parameters are largely unexplored. We aimed to characterize the relationship between self-reported sleep quality and central hemodynamics in healthy individuals. To explore the hypothesis that impairments in glucose metabolism, resulting from lack of sleep, may underlie relationships between sleep and central hemodynamic variables, we also examined associations between self-reported sleep quality and fasting blood glucose values. Methods Thirty-one healthy subjects (14 females /17 males; 20–69 years) that were free from metabolic or cardiovascular disease, and that did not take sleep medication were included in the study. Relationships between self-reported sleep quality, obtained using the Pittsburgh Sleep Quality Index (PSQI), with central hemodynamic profiles(systolic and diastolic blood pressures, pulse and augmentation pressures, augmentation index) estimated from oscillometric pulse wave analysis, and fasting blood glucose values were assessed. Results Central pulse pressure was significantly elevated (P<0.05) in poor (PSQIscore >5) compared to normal (PSQI score 0–5) self-reported sleepers. Linear regression models, adjusted for age, gender, and body mass index, demonstrated PSQI score to be an independent predictor (P<0.05) of both central pulse (β=0.469) and augmentation (β=0.364) pressures. Global PSQI scores were not related to fasting blood glucose values (r=0.045; P>0.05). Conclusion Significant relationships between central pulse and augmentationpressures and self-reported sleep quality highlight the importance of considering sleep when examining lifestyle contributors to central hemodynamics. Support No funding.
49
Bouček, Tomáš, Mikuláš Mlček, Petra Krupičková, Michal Huptych, Tomáš Belza, Otomar Kittnar, Aleš Linhart und Jan Bělohlávek. „Brain perfusion evaluated by regional tissue oxygenation as a possible quality indicator of ongoing cardiopulmonary resuscitation. An experimental porcine cardiac arrest study“. Perfusion 33, Nr. 1_suppl (Mai 2018): 65–70. http://dx.doi.org/10.1177/0267659118766282.
Der volle Inhalt der QuelleAnnotation:
Introduction: Relationship between regional tissue oxygenation (rSO2) and microcirculatory changes during cardiac arrest (CA) are still unclear. Therefore, we designed an experimental study to correlate rSO2, microcirculation and systemic hemodynamic parameters in a porcine model of CA. Methods: Ventricular fibrillation was induced in 24 female pigs (50±3kg) and left for three minutes untreated followed by five minutes of mechanical CPR. Regional and peripheral saturations were assessed by near-infrared spectroscopy, sublingual microcirculation by Sidestream Dark Field technology and continuous hemodynamic parameters, including systemic blood pressure (MAP) and carotid blood flow (CF), during baseline, CA and CPR periods. The Wilcoxon Signed-Rank test, the Friedman test and the partial correlation method were used to compare these parameters. Results: Brain and peripheral rSO2 showed a gradual decrease during CA and only an increase of brain rSO2 during mechanical CPR (34.5 to 42.5; p=0.0001), reflected by a rapid decrease of microcirculatory and hemodynamic parameters during CA and a slight increase during CPR. Peripheral rSO2 was not changed significantly during CPR (38 to 38.5; p=0.09). We only found a moderate correlation of cerebral/peripheral rSO2 to microcirculatory parameters (PVD: r=0.53/0.46; PPV: r=0.6/0.5 and MFI: r=0.64/0.52) and hemodynamic parameters (MAP: r=0.64/0.71 and CF: 0.71/0.67). Conclusions: Our experimental study confirmed that monitoring brain and peripheral rSO2 is an easy-to-use method, well reflecting the hemodynamics during CA. However, only brain rSO2 reflects the CPR efforts and might be used as a potential quality indicator for CPR.
50
Lee, En-Pei, Shao-Hsuan Hsia, Jainn-Jim Lin, Oi-Wa Chan, Jung Lee, Chia-Ying Lin und Han-Ping Wu. „Hemodynamic Analysis of Pediatric Septic Shock and Cardiogenic Shock Using Transpulmonary Thermodilution“. BioMed Research International 2017 (2017): 1–7. http://dx.doi.org/10.1155/2017/3613475.
Der volle Inhalt der QuelleAnnotation:
Septic shock and cardiogenic shock are the two most common types of shock in children admitted to pediatric intensive care units (PICUs). The aim of the study was to investigate which hemodynamic variables were associated with mortality in children with shock. We retrospectively analyzed 50 children with shock (37 septic shock cases and 13 cardiogenic shock cases) in the PICU and monitored their hemodynamics using transpulmonary thermodilution from 2003 to 2016. Clinical factors were analyzed between the patients with septic and cardiogenic shock. In addition, hemodynamic parameters associated with mortality were analyzed. The 28-day mortality was significantly higher in the septic group than in the cardiogenic group (p=0.016). Initially, the parameters of cardiac output and cardiac contractility were higher in the septic group (p<0.05) while the parameters of preload and afterload were all higher in the cardiogenic group (p<0.05). Cardiac index was significantly lower in the nonsurvivors of cardiogenic shock at the time of initial admission and after the first 24 hours (bothp<0.05), while systemic vascular resistance index (SVRI) was significantly lower in the nonsurvivors of septic shock (p<0.001). Therefore, during the first 24 hours after intensive care, SVRI and cardiac index are the most important hemodynamic parameters associated with mortality.