Hemodynamic measurements, systemic

Suarez-Bagnasco D, Armentano RL, Balay G, Cymberknop LJ, Brum J, Bia D, et al. Measurement system for an in- vitro characterization of the biomechanics and hemodynamics of arterial bifurcations. J Phys Conf Ser 2013 421 012018-26. 

Pulmonary artery catheter An invasive device used to measure hemodynamic parameters directly, including cardiac output and pulmonary artery occlusion pressure calculated parameters include stroke volume and systemic vascular resistance. 

Prednisolone can cause an abrupt rise in proteinuria in patients with nephrotic syndrome. A placebo-controlled study in 26 patients aged 18-68 years with nephrotic syndrome has clarified the mechanisms responsible for this (163). Systemic and renal hemodynamics and urinary protein excretion were measured after prednisolone (125 mg or 150 mg when body weight exceeded 75 kg) and after placebo. Prednisolone increased proteinuria by changing the size-selective barrier of the glomerular capillaries. Neither the renin-angiotensin axis nor prostaglandins were involved in these effects of prednisolone on proteinuria. 

The hemodynamic effects of compounds supposed to affect the cardiovascular system are evaluated by measuring preload and afterload of the heart, contractility, heart rate, cardiac output and peripheral or coronary flow. To measure these cardiovascular parameters accurately, the use of larger animals such as dogs or pigs is necessary. This experimental model allows the classification of test drugs according to their action as having ... 

Nalbuphine was approximately equianalgesic with morphine (1) and its hemodynamic and respiratory effects were not statistically significantly different from those of morphine (SEDA-14, 69). Other studies have shown that this also apphes to other organ systems. However, unlike morphine, nalbuphine has a ceiling effect on respiratory depression, a low incidence of dysphoric effects, and a low addiction potential. Ten patients with a history of cardiac or orthopedic problems who received intravenous nalbuphine (6-20 mg) required additional doses of morphine (15-70 mg) to relieve pain (2). However, this report was not supported by objective physiological measures or recognized pain scores. 

Measurement of electrical activity in the heart, now known as the electrocardiogram (ECG), was introduced about 75 years ago by Willem Einthoven. The ECG is simple to perform and is the most frequently used, least invasive, and cheapest cardiovascular test. ° It remains the procedure of first choice for evaluation of chest pain, dizziness, or syncope. In its simplest interpretation, the ECG characterizes rhythms and conduction abnormalities. However, the ECG also provides, by inference, information about the anatomy and structures of the heart, pathophysiologic changes, and hemodynamics of the CVD system. ECG abnormalities are often the earliest sign of adverse drug effects, ischemia, and electolyte abnormalities. 

Invasive hemodynamic monitoring usually is performed with a flow-directed pulmonary artery (PA) or Swan-Ganz catheter placed percutaneously through a central vein and advanced through the right side of the heart and into the PA. Inflation of a balloon proximal to the end port allows the catheter to wedge, yielding the PAOP, which estimates the pulmonary venous (left atrial) pressure and, in the absence of intracardiac shunt or mitral valve or pulmonary disease, left ventricular diastolic pressure. Additionally, cardiac output may be measured and systemic vascular resistance (SVR) calculated. Normal values for hemodynamic parameters are listed in Table 14—12. 

Therapy with vasopressors and inotropes is continued until the myocardial depression and vascular hyporesponsive-ness of septic shock improve, usually measured in hours to days. Discontinuation of vasopressor or inotropic therapy should be executed slowly therapy should be "weaned" to avoid a precipitous worsening in regional and systemic hemodynamics. 

Patients with CKD are at increased risk of cardiovascular disease, independent of the etiology of their kidney disease. While a clearly unique pathogenesis of cardiovascular disease specific to CKD has not been identified, it is known that manifestations of kidney disease are contributory. Risk factors for cardiovascular disease in this population include hemodynamic and metabolic abnormalities, as well as hypertension, dyslipidemia, elevated homocysteine levels, anemia, hyperparathyroidism, malnutrition, and oxidative stress. Hypertension induced by volume expansion and increased systemic vascular resistance increases myocardial work and contributes to development of left ventricular hypertrophy (LVH). Hyperlipidemia may enhance atherogenesis, while some uremic toxins can decrease myocardial contractflity. In addition, uremic toxins can induce pericarditis, a potentially fatal complication. Currently, measures to screen this high-risk population for cardiovascular risk factors are not routine. ... 

The same ventricle may be coupled to a pathological arterial system, for example, one with doubled peripheral resistance R. As expected, increased peripheral resistance raises arterial pulse pressure (to 140/95 mmHg) and impedes the ventricle s ability to eject blood (Figure 8.6). The ejection fraction decreases to 50% in this experiment. Other experiments, such as altered arterial stiffness, may be performed. The model s flexibility allows description of heart pathology as well as changes in blood vessels. This one equation (Equation 8.8) with one set of measured parameters is able to describe the wide range of hemodynamics observed experimentally [11],... 

The emerging role of micro- and nanoscale hot-wire anemometry would likely accelerate the translation of in vitro devices to in vivo applications, thereby bridging the lab-to-patient gap. Real-time measurements of intravascular physical parameters, specifically shear stress, temperature, pressure, and flow rate, provide a basis to link hemodynamics with biochemical events in blood vessels. The complex curvature of the vascular system requires small, minimally invasive sensors to discretely measure in real time intravascular physical parameters with minimal blood flow disturbance. To achieve this, flexible micro-and nanoscale sensors would allow for steering in the complicated anatomy in biological systems (Fig. 11). In summary, the utilization of micro- or nanoscale sensors provides a quantitative assessment of vascular hemodynamics. This approach lends itself to applications in broad areas of medicine and physiology and is particularly relevant to quantitative studies of cancer biology as well as... 

Several methods are used for the VA flow volume measurement during hemodialysis [30]. Mostly, they are based on dilution techniques and are used for early detection of access stenosis. However, they are important also in terms of systemic hemodynamics. It should be especially kept in mind that the obtained... 

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