Sun28November0333PM 21

Lung compliance:

True / False

Is decreased in the elderly Correct

Varies with lung volume Correct

The units are cmH2O/L Incorrect answer selected

Is approximately linear in the normal tidal volume range Incorrect answer selected

Is frequency dependent when measured dynamically Correct

Explanation

Compliance of the lung is determined by plotting a graph of volume (y axis) against pressure (x axis). The pressure-volume curve is sigmoid in shape. The relationship between lung volume and intra-pleural pressure is approximately linear in the middle range, which includes normal tidal ventilation.

Compliance is decreased at low and high volumes, with pulmonary oedema and pulmonary fibrosis. It increases with age.

The unit of compliance is volume change per unit pressure (L/cmH2O). A normal value of lung compliance is 100 mL/cmH2O.

The dynamic compliance is inversely proportional to the frequency of ventilation.

Answer Statistics

Not enough data to display the statistics

Average score: 67.74%

Times answered: 287