The Mechanics of Breathing

The mechanics of breathing in a child are influenced by their anatomy. The chest wall is compliant as the ribs are cartilaginous in nature and lay more horizontally than in an adult.

In addition, the accessory muscles are immature and the diaphragm can become easily fatigued.

An increase in inspiratory effort causes tracheal tug, intercostal muscle in-drawing and sternal recession, all of which reduce the mechanical efficiency.

Lung capacity

Children have a small functional residual lung capacity with little respiratory reserve. In times of increased oxygen demand and an increased metabolic demand, children can decompensate quickly.

Volumes and capacities Ref: