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Impedance Plethysmography
Impedance cardiography (ICG) is a non-invasive technology measuring total electrical conductivity of the thorax and its changes in time to process continuously a number of cardiodynamic parameters, such as stroke volume (SV), heart rate (HR), cardiac output (CO), ventricular ejection time (VET), pre-ejection period and used to detect the impedance changes caused by a high-frequency, low magnitude current flowing through the thorax between additional two pairs of electrodes located outside of the measured segment. The sensing electrodes also detect the ECG signal, which is used as a timing clock of the system. Introduction Impedance cardiography (ICG), also referred to as electrical impedance plethysmography (EIP) or Thoracic Electrical Bioimpedance (TEB) has been researched since the 1940s. NASA helped develop the technology in the 1960s. The use of impedance cardiography in psychophysiological research was pioneered by the publication of an article by Miller and Horvath in 1978 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Non-invasive Procedure
A medical procedure is defined as ''non-invasive'' when no break in the skin is created and there is no contact with the mucosa, or skin break, or internal body cavity beyond a natural or artificial body orifice. For example, deep palpation and percussion are non-invasive but a rectal examination is invasive. Likewise, examination of the ear-drum or inside the nose or a wound dressing change all fall outside the definition of ''non-invasive procedure''. There are many non-invasive procedures, ranging from simple observation, to specialised forms of surgery, such as radiosurgery. Extracorporeal shock wave lithotripsy is a non-invasive treatment of stones in the kidney, gallbladder or liver, using an acoustic pulse. For centuries, physicians have employed many simple non-invasive methods based on physical parameters in order to assess body function in health and disease (physical examination and inspection), such as pulse-taking, the auscultation of heart sounds and lung sounds ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Relationship Between Aortic Blood Pressure And Aortic Blood Flow
Relationship most often refers to: * Family relations and relatives: consanguinity * Interpersonal relationship, a strong, deep, or close association or acquaintance between two or more people * Correlation and dependence, relationships in mathematics and statistics between two variables or sets of data * Semantic relationship, an ontology component * Romance (love), a connection between two people driven by love and/or sexual attraction Relationship or Relationships may also refer to: Arts and media * "Relationship" (song), by Young Thug featuring Future * "Relationships", an episode of the British TV series ''As Time Goes By'' * The Relationship, an American rock band ** ''The Relationship'' (album), their 2010 album * The Relationships, an English band who played at the 2009 Truck Festival * ''Relationships'', a 1994 album by BeBe & CeCe Winans * ''Relationships'', a 2001 album by Georgie Fame * "Relationship", a song by Lakeside on the 1987 album ''Power'' * "Relation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Impedance Measurements
Impedance is the complex-valued generalization of resistance. It may refer to: *Acoustic impedance, a constant related to the propagation of sound waves in an acoustic medium *Electrical impedance, the ratio of the voltage phasor to the electric current phasor, a measure of the opposition to time-varying electric current in an electric circuit **High impedance, when only a small amount of current is allowed through ** Characteristic impedance of a transmission line **Impedance (accelerator physics), a characterization of the self interaction of a charged particle beam ** Nominal impedance, approximate designed impedance **Impedance matching, the adjustment of input impedance and output impedance *Mechanical impedance, a measure of opposition to motion of a structure subjected to a force *Wave impedance, a constant related to electromagnetic wave propagation in a medium **Impedance of free space The impedance of free space, , is a physical constant relating the magnitudes of the ele ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diagnostic Cardiology
Diagnosis is the identification of the nature and cause of a certain phenomenon. Diagnosis is used in many different disciplines, with variations in the use of logic, analytics, and experience, to determine " cause and effect". In systems engineering and computer science, it is typically used to determine the causes of symptoms, mitigations, and solutions. Computer science and networking * Bayesian networks * Complex event processing * Diagnosis (artificial intelligence) * Event correlation * Fault management * Fault tree analysis * Grey problem * RPR Problem Diagnosis * Remote diagnostics * Root cause analysis * Troubleshooting * Unified Diagnostic Services Mathematics and logic * Bayesian probability * Block Hackam's dictum * Occam's razor * Regression diagnostics * Sutton's law copy right remover block Medicine * Medical diagnosis * Molecular diagnostics Methods * CDR Computerized Assessment System * Computer-assisted diagnosis * Differential diagnosis * Medical diag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interstitial Fluid
In cell biology, extracellular fluid (ECF) denotes all body fluid outside the cells of any multicellular organism. Total body water in healthy adults is about 60% (range 45 to 75%) of total body weight; women and the obese typically have a lower percentage than lean men. Extracellular fluid makes up about one-third of body fluid, the remaining two-thirds is intracellular fluid within cells. The main component of the extracellular fluid is the interstitial fluid that surrounds cells. Extracellular fluid is the internal environment of all multicellular animals, and in those animals with a blood circulatory system, a proportion of this fluid is blood plasma. Plasma and interstitial fluid are the two components that make up at least 97% of the ECF. Lymph makes up a small percentage of the interstitial fluid. The remaining small portion of the ECF includes the transcellular fluid (about 2.5%). The ECF can also be seen as having two components – plasma and lymph as a delivery system ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Timing Considerations Of Hemodynamic Modulation
Timing is the tracking or planning of the spacing of events in time. It may refer to: * Timekeeping, the process of measuring the passage of time * Synchronization, controlling the timing of a process relative to another process * Time metrology, the measurement of time Timing in different fields * Timing (comedy), use of rhythm, tempo and pausing to enhance comedy and humour * Timing (linguistics), rhythmic division of time into equal portions by a language * Timing (music), ability to "keep time" accurately and to synchronise to an ensemble * Color timing, photochemical process of altering and enhancing the color of an image * Ignition timing, timing of piston and crankshaft so that a spark will occur near the end of the compression stroke * Market timing, by attempting to predict future market price movements * Memory timings (or RAM timings), measure of the performance of DRAM memory * Valve timing In a piston engine, the valve timing is the precise timing of the opening ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aortic Valve
The aortic valve is a valve in the heart of humans and most other animals, located between the left ventricle and the aorta. It is one of the four valves of the heart and one of the two semilunar valves, the other being the pulmonary valve. The aortic valve normally has three cusps or leaflets, although in 1–2% of the population it is found to congenitally have two leaflets. The aortic valve is the last structure in the heart the blood travels through before stopping the flow through the systemic circulation. Structure The aortic valve normally has three cusps however there is some discrepancy in their naming. They may be called the left coronary, right coronary and non-coronary cusp. Some sources also advocate they be named as a left, right and posterior cusp. Anatomists have traditionally named them the left posterior (origin of left coronary), anterior (origin of the right coronary) and right posterior. The three cusps, when the valve is closed, contain a sinus called an a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ohm's Law
Ohm's law states that the current through a conductor between two points is directly proportional to the voltage across the two points. Introducing the constant of proportionality, the resistance, one arrives at the usual mathematical equation that describes this relationship: :I = \frac, where is the current through the conductor, ''V'' is the voltage measured ''across'' the conductor and ''R'' is the resistance of the conductor. More specifically, Ohm's law states that the ''R'' in this relation is constant, independent of the current. If the resistance is not constant, the previous equation cannot be called ''Ohm's law'', but it can still be used as a definition of static/DC resistance. Ohm's law is an empirical relation which accurately describes the conductivity of the vast majority of electrically conductive materials over many orders of magnitude of current. However some materials do not obey Ohm's law; these are called non-ohmic. The law was named after t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stroke Volume
In cardiovascular physiology, stroke volume (SV) is the volume of blood pumped from the left ventricle per beat. Stroke volume is calculated using measurements of ventricle volumes from an echocardiogram and subtracting the volume of the blood in the ventricle at the end of a beat (called end-systolic volume) from the volume of blood just prior to the beat (called end-diastolic volume). The term ''stroke volume'' can apply to each of the two ventricles of the heart, although it usually refers to the left ventricle. The stroke volumes for each ventricle are generally equal, both being approximately 70 mL in a healthy 70-kg man. Stroke volume is an important determinant of cardiac output, which is the product of stroke volume and heart rate, and is also used to calculate ejection fraction, which is stroke volume divided by end-diastolic volume. Because stroke volume decreases in certain conditions and disease states, stroke volume itself correlates with cardiac function. Calculati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemodynamic
Hemodynamics or haemodynamics are the dynamics of blood flow. The circulatory system is controlled by homeostatic mechanisms of autoregulation, just as hydraulic circuits are controlled by control systems. The hemodynamic response continuously monitors and adjusts to conditions in the body and its environment. Hemodynamics explains the physical laws that govern the flow of blood in the blood vessels. Blood flow ensures the transportation of nutrients, hormones, metabolic waste products, oxygen, and carbon dioxide throughout the body to maintain cell-level metabolism, the regulation of the pH, osmotic pressure and temperature of the whole body, and the protection from microbial and mechanical harm. Blood is a non-Newtonian fluid, and is most efficiently studied using rheology rather than hydrodynamics. Because blood vessels are not rigid tubes, classic hydrodynamics and fluids mechanics based on the use of classical viscometers are not capable of explaining haemodynamics. The st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrical Cardiometry
Electrical cardiometry is a method based on the model of ''Electrical Velocimetry'', and non-invasively measures stroke volume (SV), cardiac output (CO), and other hemodynamic parameters through the use of 4 surface ECG electrodes. Electrical cardiometry is a method trademarked by Cardiotronic, Inc., and is U.S. FDA approved for use on adults, children, and neonates. Overview * The method of electrical cardiometry requires the use of 4 ECG electrodes, 2 attached to the left side of the neck and 2 attached at the lower thorax. * An electrical alternating current (AC) of constant amplitude is applied via the pair of outer electrodes toward the thorax and in particular the ascending and descending aorta. * Current is directed toward the aorta because blood is the most conductive material in the thorax. * The ratio of applied current and measured voltage equals the conductivity (or bioimpedance), which is recorded over time.http://cardiotronic.net/en/products/cardiac_output_mon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
