Total Lung Capacity
Also written as: TLC — Total Lung Capacity
The maximum volume of air the lungs can contain after a maximal inspiratory effort, encompassing all lung subdivisions.
Full Definition
Total lung capacity (TLC) is the sum of all lung volume compartments: tidal volume, inspiratory reserve volume, expiratory reserve volume, and residual volume. In paediatric pulmonology, TLC is measured by body plethysmography or gas dilution techniques, with plethysmography preferred when gas trapping is suspected. Reduced TLC indicates restrictive lung disease, whereas normal or elevated TLC with increased residual volume (RV) and RV/TLC ratio suggests air trapping, as seen in obstructive disease. Editors should ensure TLC is not confused with functional residual capacity (FRC) or vital capacity (VC) in manuscripts.
Usage
Usage note: Expand TLC on first reference. In paediatric reports, always specify the measurement technique (plethysmography vs. gas dilution), as values may differ.
In Context
- "Body plethysmography revealed a reduced total lung capacity of 68% predicted, confirming a restrictive ventilatory defect in the seven-year-old." — Pulmonary function test report
- "The author wrote 'vital capacity' when citing the full lung volume; the editor queried whether 'total lung capacity' was intended." — Manuscript editorial query