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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 ?
Airway obstruction after acute ozone exposure in BALB/c mice using barometric plethysmography.
There is a considerable high frequency noise present in the sampled sensor signal of the inductance plethysmography respiration.
The technicians were trained in whole-body plethysmography techniques, and the laboratory supervisor also checked all the steps involved in the test procedures in terms of adherence to the American Thoracic Society and American Thoracic Society/European Respiratory Society guidelines (9-12).
PneumaCare is a Cambridge, UK-based company that is leveraging its patented structured light Plethysmography technology to develop and market innovative respiratory imaging systems.
2008) to assess % fat, whereas the current study used air-displacement plethysmography.
It has an added discussion of the concepts of high-flow nasal cannula therapy and body plethysmography, a revised discussion on the normal physiology of ventilation and discussion of modes of ventilation, incorporation of the American Association for Respiratory Care (AARC) Clinical Practice Guidelines, elimination of older equipment, more equipment, more clinical scenarios and critical thinking activities, more generic troubleshooting flowcharts and boxes, and other changes.
Air plethysmography was used to measure venous volume and time to fill 90% of the venous volume, which improved significantly in all types of stockings trialed vs.
The blood pressure and heart rate were monitored using non-invasive BP-98A tail-cuff plethysmography (Softron Co.
This article explores new stimulus materials for use with penile plethysmography (PPG) assessments.
Measurement of lung function in awake 2-4-year-old asthmatic children during methacholine challenge and acute asthma: a comparison of the impulse oscillation technique, the interrupter technique, and transcutaneous measurement of oxygen versus whole-body plethysmography.