Plethysmography


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Related to Plethysmography: Impedance plethysmography

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.

O. M. BENIUMOV

References in periodicals archive ?
We found significant differences in % body fat and fat-free mass of non-athletes between bioelectrical impedance and air displacement plethysmography. According to our results BIA slightly overestimates % BF of non-athletes.
However, the observation of relevant effects without noise during the active period (e.g., food and water intake and various sleep parameters) and during the rest period (e.g., plethysmography parameters) might suggest an impact of sleep habituation and/or sleep pressure.
In addition, the forward stepwise regression analysis was used to identify the variables provided by spirometry and body plethysmography that were independently related to parameters of the [N.sub.2]SBW test after considering confounding factors (including demographic and clinical data).
(39.) Criee CP, Sorichter S, Smith HI, et al; Working Group for Body Plethysmography of the German Society for Pneumology and Respiratory Care.
In the current study, vascular function was measured with strain-gauge plethysmography, which measures the whole limb blood flow.
Further, total lung volume was acquired in supine position in qCT rather than sitting TLC in body plethysmography. As shown previously, posture has an effect on measured lung volumes and thereby might have strengthened the named difference [33].
(ii) Underwater weighing and air displacement plethysmography (ADP) methods: underwater weighing and air displacement plethysmography (ADP) are considered undisputed reference methods for measuring fat and fat-free mass, and they are based on body density.
Anthropometric data for the participants are listed in Table 1, along with the results for biothesiometry, venous occlusion plethysmography, and arterial samples of markers of bone health taken prior to the cooling of the feet ([t.sub.start]).
Hannapel, "Electrical impedance plethysmography," Circulation, vol.
In order to determine whether tomatidine treatment affects AHR, airway mechanics were measured using a whole-body plethysmography chamber to record the signal as an enhanced pause (Penh).
Use of hand-to-hand impedancemetry to predict body composition of African women as measured by air displacement plethysmography. Eur J Clin Nutr.