What does elastance (e) represent?

Elastance is a mechanical property that reflects the tendency of a structure, such as lung tissue, to return to its original shape after deformation when a distorting force (such as pressure) is removed. In the context of respiratory mechanics, elastance is the inverse of compliance; while compliance measures how much volume changes per unit pressure applied, elastance focuses on the ability of the lungs to recoil after being stretched or expanded. Higher elastance indicates a stiffer lung that resists deformation and quickly returns to its resting state once the pressure is reduced.

Understanding elastance is crucial in clinical scenarios, particularly when assessing and managing patients with conditions such as pulmonary fibrosis where elastance can be markedly increased, leading to reduced lung compliance. This concept plays an integral role in mechanical ventilation settings as it informs decisions about ventilator settings and oxygenation strategies.