https://wikimd.org/index.php?action=history&feed=atom&title=Residual_volume 2026-04-26T02:32:13Z Revision history for this page on the wiki MediaWiki 1.44.2 https://wikimd.org/index.php?title=Residual_volume&diff=5344230&oldid=prev 2024-03-02T15:53:18Z

<p>CSV import</p> <p><b>New page</b></p><div>&#039;&#039;&#039;Residual volume&#039;&#039;&#039; (RV) is the volume of air remaining in the lungs after a maximal exhalation. It is a component of [[lung volumes]] and capacities, which are measured in pulmonary function tests. <br /> <br /> ==Definition==<br /> Residual volume is defined as the volume of air still remaining in the lungs after the most forcible expiration possible. This volume cannot be measured, only calculated. It is a standard part of lung volumes, along with [[tidal volume]], [[inspiratory reserve volume]], and [[expiratory reserve volume]]. <br /> <br /> ==Measurement==<br /> Residual volume can be measured using a number of techniques, including body plethysmography, helium dilution, and nitrogen washout. These techniques are often used in [[pulmonary function tests]] to assess lung health and diagnose respiratory conditions.<br /> <br /> ===Body Plethysmography===<br /> [[Body plethysmography]] is a method of measuring lung volumes that involves the use of a body box or plethysmograph. The subject breathes against a closed system, and changes in pressure allow for the calculation of lung volumes, including residual volume.<br /> <br /> ===Helium Dilution===<br /> The [[helium dilution]] technique involves the subject breathing in a known volume of helium. The concentration of helium in the lungs is then measured, and this information is used to calculate lung volumes.<br /> <br /> ===Nitrogen Washout===<br /> In the [[nitrogen washout]] technique, the subject breathes 100% oxygen, and the exhaled gas is analyzed for nitrogen content. The volume of nitrogen washed out of the lungs is used to calculate lung volumes.<br /> <br /> ==Clinical Significance==<br /> Residual volume can be increased in conditions such as [[chronic obstructive pulmonary disease]] (COPD) and [[asthma]], where airway obstruction leads to air trapping in the lungs. Conversely, it can be decreased in conditions such as [[restrictive lung disease]], where lung expansion is limited.<br /> <br /> ==See Also==<br /> * [[Lung volumes]]<br /> * [[Pulmonary function tests]]<br /> * [[Chronic obstructive pulmonary disease]]<br /> * [[Asthma]]<br /> * [[Restrictive lung disease]]<br /> <br /> [[Category:Respiratory physiology]]<br /> [[Category:Pulmonology]]<br /> {{Pulmonology-stub}}</div>

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