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Therapeutic Approaches in Acute Heart Failure
Published in Andreas P. Kalogeropoulos, Hal A. Skopicki, Javed Butler, Heart Failure, 2023
Getu Teressa, Rachel A. Bright, Andreas P. Kalogeropoulos
Clinical trajectory monitoring assesses resolution of signs and symptoms of congestion, adequate perfusion, end-organ function recovery, and maintenance of acceptable vital signs. Assessing improvement in dyspnea, orthopnea, crackles, and jugular venous pressure (JVP) are important indicators of treatment trajectory as they indirectly reflect left-sided filling pressure. The presence of rales or fine crackles usually indicates higher filling pressures than the baseline and can be present before detection of pulmonary edema radiographically. However, these findings can be often absent in chronic HF patients owing to compensation of the pulmonary lymphatic system. JVP measures right-sided filling pressure and can serve as a surrogate for left-sided filling pressures. However, other processes may lead to disproportionately higher right-sided filling pressure than left-sided filling pressure. In the case of uncertainty in assessing intracardiac filling pressures clinically, invasive hemodynamic monitoring can be considered to guide therapy in the setting of respiratory distress or clinical evidence of impaired perfusion (ACCF/AHA class I, Level C). However, pulmonary artery catheterization does not reduce mortality or length of hospitalization, and in fact may increase adverse events.86 Therefore, routine use of invasive hemodynamic monitoring is not recommended.82
General Principles for Measuring Arterial Waves
Published in Wilmer W Nichols, Michael F O'Rourke, Elazer R Edelman, Charalambos Vlachopoulos, McDonald's Blood Flow in Arteries, 2022
Transducers are used to convert time-varying physiologic events (or variables) into electric signals. With the event avail able as an electric signal, the maximum amount of information can be obtained. In cardiology and cardiovascular physiology, the hemodynamic events most often measured are pressure, flow (and velocity), volume and length (or diameter). The transducer used to measure these variables should obey the three criteria for the faithful reproduction of an event: ampli tude linearity, adequate frequency response and phase linear ity (Nichols et al., 1994b, 1994c; Geddes and Baker, 1975).
Motion of blood in the venous system—novel findings
Published in Dinker B. Rai, Mechanical Function of the Atrial Diastole, 2022
Blood pressure is the only parameter that we use to understand the hemodynamics of blood in the arteries at the present time. Technically, venous pressure cannot be measured by a sphygmomanometer. We have created a method to measure the weight of the column of the blood in the venous system and we consider it to be venous pressure in order to understand the venous hemodynamics. This is because pressure was the only age-old parameter by which we understood the hemodynamics. We have applied the same parameter when it comes to evaluating and treating diseases of the venous system.
Increased thoracic fluid content is associated with higher risk for pneumonia in patients undergoing maintenance hemodialysis
Published in Renal Failure, 2023
Lijuan Yan, Yumei Qiu, Jin Liu, Jining Wu, Junwei Yang, Weichun He
Bio-Noninvasive Hemodynamic Monitor (BioZ-2011, Medean Medical Equipment Co., Shenzhen, China) was used to noninvasively measure hemodynamic parameters. The monitoring principle has been described in detail in the previous study [10]. Briefly, the monitor used a 2.5 mA at 70 kHz current via atetrapolar system of four sensors, two of which were placed on the neck above the clavicle and two others were placed on the chest at the level of the tip of the xiphoid process. Each member of a pair were 180° apart, both at the top and at the bottom of the thoracic cavity. Voltage pickup electrodes on the sensors bridge the thorax for an axial measurement of voltage when current is introduced through the outer electrodes on each sensor. The algorithm allows the monitor to calculate hemodynamic-related parameters based on variations in thoracic bio-impedance due to changes in blood volume and velocity in the aorta. TFC, cardiac output (CO), cardiac index (CI), systemic vascular resistance index (SVRI), and left cardiac work index (LCWI) were measured and obtained directly from the monitor without using indwelling catheters. Systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate were measured concurrently. The placement of electrodes on the body surface is presented in Supplemental Figure 1.
Effect of Combined Grape Seed Extract and L-Citrulline Supplementation on Hemodynamic Responses to Exercise in Young Males
Published in Journal of Dietary Supplements, 2023
Brian Shariffi, Katherine Dillon, Trevor Gillum, William Boyer, Sean Sullivan, Esther Lee, Jong-Kyung Kim
SV and heart rate (HR) were measured by impedance cardiography (Physioflow, Manatec Biomedical Q-link, Paris, France). This device evaluates real-time cardiac output data, as well as other hemodynamic responses. The bioimpedance device consists of six impedance cardiography electrodes, two positioned above the clavicle in the carotid sinus of the left side of the neck, one at the fourth intercostal space of the right rib, two electrodes positioned at the xiphoid process, and one positioned at the anterior axillary line of the left arm at the fifth intercostal space. Two of the electrodes (electrodes located at the anterior axillary line and the fourth intercostal) provide a visual of a one lead ECG. Impedance cardiography measures electrical currents in thorax impedance during the cardiac cycle to calculate SV (26). This cardiography is a device that gives off high-frequency (75 kHz) and low-magnitude (1.8 mA) electrical stimuli through the use of skin electrodes during the cardiac cycle, and then relays a waveform from which SV is calculated (27). Cardiac output was calculated according to the formula: cardiac output = HR × SVi × BSA, where HR was gathered from the one lead ECG at the R-R interval. SVi is the SV index which is calculated by SV/BSA. BSA (body surface area, in m2) was calculated using the Haycock formula: BSA = 0.024265 × BM0.5378 × H0.3964, where BM is the body mass in kilograms and H is the height in centimeters. The Physioflow technique has been known to a reliable and valid method against the direct Fick method at rest and during exercise (27).
Pulsatile flow of thixotropic blood in artery under external body acceleration
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2023
Louiza Cheffar, Abdelhakim Benslimane, Djamel Sadaoui, Adel Benchabane, Karim Bekkour
Hemodynamics is an area of science concerned with the dynamics of blood flow and explains the physical laws that govern the flow of blood in the blood vessels through which the flow occurs. Simulation of blood flow in the arterial network system will provide a better understanding of the physiology of human body. Hence, detailed knowledge of blood flow is a fundamental key concept in the understanding of cardiovascular system and in the detection of arterial diseases. However, the effects of thixotropy in terms of the viscosity ratio μr, external acceleration characterized by the parameter Ag, the pressure ratio e and the frequency fb on the flow variables are investigated. The corresponding flow variables namely: velocity and wall shear stress have been analyzed and discussed.