Extremely premature infants are often born with severe respiratory failure. They are usually treated using conventional mechanical ventilation. However, the high airway pressures and volumes associated with conventional ventilation techniques can sometimes cause lung damage in this fragile group.

High frequency ventilation is a relatively new approach developed to combat these problems by ventilating very rapidly (hundreds of breaths per minute) with teaspoon size breaths. Although this new ventilation technique significantly reduces the risk of lung damage in ventilated premature infants, it can be difficult to apply correctly.

A new expandable belt worn around the infant’s chest has been developed to assist with this process. The amount of light transmitted through an optical fibre stitched into the belt is proportional to the size of the chest. Hence, dynamic monitoring of the light intensity transmitted through the belt can be used to accurately measure the tiny expansions and contractions of the chest wall which occur during high frequency ventilation.