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Related to Plethysmography: Impedance plethysmography



in medicine and physiology, a method of continuous graphic recording of variations in the volume of a human or animal organ as modified by the circulation of blood. Plethysmography is used to study cardiovascular function and changes in the distribution of blood caused by physical and mental work, fatigue, and emotional responses; it is also used to determine the effects of heat, cold, and tactile and other stimuli and of hypotensive and hypertensive agents. Plethysmography is used in clinical analysis to evaluate vascular tonus and elasticity, pulse volume, and central nervous system function and to investigate corticovisceral functioning by registering the reaction of blood vessels to stimuli.

Figure 1. Plethysmograph: (1) cylindrical container, (2) rubber cuff, (3) tube connecting bottle to container, (4) tube connecting container to Marey capsule, (5) bottle for water, (6) kymograph

The main part of a very simple plethysmograph (Figure 1) is a container of suitable size and shape in which the part, for example, hand, leg, or finger, is placed. In animal experiments a kidney, heart, or spleen may be studied. The container is filled with water and hermetically sealed. (In Figure 1 a rubber cuff is used.) Changes in the water level in the container reflect fluctuations in blood volume in the organ or part and are recorded in the form of a curve called a plethysmogram. The plethysmogram shows small fluctuations in blood pressure corresponding to pulse and somewhat larger ones corresponding to respiration; large variations reflect vascular reactions to various stimuli. More advanced methods of plethysmography include (1) photoplethysmography, in which light is directed through an organ, such as an ear or finger, onto a photoelectric cell, or light is reflected from the organ, (2) rheoplethysmography, and (3) dielectrography, or rheocardiography. The last two methods are based on the direct recording of fluctuations in the electrical properties of an organ, which reflect the dynamics of the organ’s blood supply.


References in periodicals archive ?
Based on product, the global body composition analyzers market is segmented into Bioimpedance Analyzers (BIA), Dual-Energy X-ray Absorptiometry (DEXA), Skinfold Calipers, Air Displacement Plethysmography (ADP), and Hydrostatic Weighing, wherein the bioimpedance analyzers segment dominates the market with 40.
Odeshoo, Of Penology and Perversity: The Use of Penile Plethysmography on Convicted Child Sex Offenders, 14 Temp.
Interrupter technique versus plethysmography for measurement of respiratory resistance in children with asthma or cystic fibrosis.
These include infant spirometry (raised volume rapid thoracoabdominal compression (RVRTC)), plethysmography, multiple breath inert gas washout tests, forced oscillation technique and the interrupter technique.
We used plethysmography to measure thoracic gas volume (TGV) as described previously (Janosi et al.
Body weight and tail mean blood pressure (MBP) was assessed weekly by tail-cuff plethysmography (Coda-VPR, Kent Scientific, Torrington, CT, USA).
Venous occlusion plethysmography and radionuclide techniques are the most commonly used invasive methods that allow a quantitative description of local and regional blood flow (De Graaff et al.
Endothelial dysfunction, measured by reactive hyperaemia using strain-gauge plethysmography, is an independent predictor of adverse outcome in heart failure.
Pulse plethysmography (PPG) was described in the 1930s (1), prior to the development of the pulse oximeter, and the combination of the two approaches in the modern pulse oximeter allows continuous non-invasive monitoring of arterial oxygenation, pulse rate and pulse plethysmograph waveform analysis (2).
Another study using forearm plethysmography tested a bradykinin B2 receptor antagonist, based on the hypothesis that endogenous bradykinin is a mediator of reperfusion injury (82).
Body fat, weight and volume of the babies were also measured with air displacement plethysmography using the Pea Pod Infant Body Composition System.