Related Experiment Video
Updated: Jul 17, 2026
07:18
Evaluation of Capillary and Other Vessel Contribution to Macular Perfusion Density Measured with Optical Coherence Tomography Angiography
Published on: February 18, 2022
Closing volume: a reappraisal (1967-2007)
Joseph Milic-Emili1, Roberto Torchio, Edgardo D'Angelo
1Meakins-Christie Laboratories, McGill University, 3626 St. Urbain Street, H2X2P2, Montreal, QC, Canada. joseph.milic-emili@mcgill.ca
European Journal of Applied Physiology
|January 24, 2007
Summary
Closing volume (CV) measurement detects tidal airway closure, which impairs gas exchange and risks airway injury. This condition, where CV exceeds end-expiratory lung volume (EELV), is common in lung diseases and aging.
Area of Science:
- Pulmonary Physiology
- Respiratory Medicine
Background:
- Closing volume (CV) measurement is key to identifying tidal airway closure.
- Tidal airway closure involves cyclic opening/closure of peripheral airways, leading to ventilation inhomogeneity and impaired gas exchange.
- This closure increases the risk of peripheral airway injury.
Purpose of the Study:
- To review the causes and consequences of tidal airway closure.
- To highlight the clinical significance of CV exceeding EELV.
- To propose 'open volume' assessment as a simpler alternative to CV measurement.
Main Methods:
- Review of existing literature on closing volume and tidal airway closure.
- Analysis of conditions associated with increased CV (COPD, asthma) and decreased EELV (obesity, heart failure).
- Discussion of the impact of aging on tidal airway closure risk.
Main Results:
- Tidal airway closure occurs when CV exceeds EELV.
- Conditions like COPD, asthma, obesity, and heart failure are associated with tidal airway closure.
- Aging enhances the risk of tidal airway closure.
Conclusions:
- Tidal airway closure leads to impaired gas exchange and peripheral airway disease.
- Assessment of 'open volume' is proposed as a more practical alternative to CV measurement.
- Further studies are recommended to explore tidal airway closure and its management.
Related Concept Videos
01:26Unsoundness of Aggregate due to Volume Change
Unsoundness in aggregates due to volume changes is primarily caused by the physical alterations aggregates undergo, such as freezing and thawing, thermal changes, and wetting and drying. Unsound aggregates, when subjected to these changes, result in volume change upon disintegration. This, in turn, contributes to the deterioration of concrete, including scaling, pop-outs, and cracking. Particular types of aggregates, such as porous flints, cherts, and those containing clay minerals, are...
01:20Volume of Distribution
The apparent volume of distribution (Vd) is a crucial pharmacokinetic parameter representing the hypothetical body fluid volume into which a drug disperses. It is calculated based on the total amount of drug in the body (estimated from the administered dose and bioavailability) divided by the plasma drug concentration. The total amount of drug in the body does not directly refer to the dose given but is derived by accounting for absorption, distribution, metabolism, and excretion processes.
01:17Work Done During Volume Change
In mechanics, work is done on an object when the force acting on it displaces the object. In thermodynamics, work done on a system can be estimated when the system's volume changes during any thermodynamic process.
Consider a gas confined to a cylinder fitted with a movable piston at one end. If the gas expands from volume V1 to volume V2, it exerts a force on the piston, such that the piston moves by a distance dr.
The work done by the gas on the piston can be expressed as
Consider a gas confined to a cylinder fitted with a movable piston at one end. If the gas expands from volume V1 to volume V2, it exerts a force on the piston, such that the piston moves by a distance dr.
The work done by the gas on the piston can be expressed as
01:20Actuarial Approach
The actuarial approach, a statistical method originally developed for life insurance risk assessment, is widely used to calculate survival rates in clinical and population studies. This method accounts for participants lost to follow-up or those who die from causes unrelated to the study, ensuring a more accurate representation of survival probabilities.
Consider the example of a high-risk surgical procedure with significant early-stage mortality. A two-year clinical study is conducted,...
Consider the example of a high-risk surgical procedure with significant early-stage mortality. A two-year clinical study is conducted,...
01:27Calculation of Volume of Solids by Integration
Volume calculation often begins with simple geometric solids. For example, the volume of a rectangular box is obtained by multiplying the area of its base by its height. This straightforward approach relies on the fact that the cross-sectional area of the box remains constant throughout its length. Many real-world objects, however, do not have uniform cross-sections, and their volumes cannot be determined using elementary geometric formulas.To address this limitation, the Slicing Method...
01:25Finding Volume Using Cross-Sectional Area
For solids whose cross-sectional areas vary in a predictable way, volume can be determined by integrating these areas along an axis perpendicular to the slices. This approach is particularly useful for polyhedral solids, where classical geometric formulas may not be immediately applicable. A tetrahedron provides a clear example of how cross-sectional integration can be applied to a three-dimensional object with continuously changing geometry.Consider a tetrahedron with height h and a base that...