An extreme example of pendelluft is found in a spontaneously breathing patient with an
open hemithorax or large
flail segment. During the inspiratory phase, the contralateral lung (with a closed / intact chest wall) will expand with most of the tidal volume, with the open
plura or paradoxical chest wall movement preventing expansion of the ipsilateral lung. However, during the expiratory phase, there will be gas flow (pendelluft) from the contralateral lung to the lung ipsilateral to the open thorax. Inspiration can also cause gas movement from the ipsilateral to the contralateral lung. Pendelluft is one mechanism by which ventilation occurs during
High-frequency oscillatory ventilation A final example of pendelluft is if two separate individuals are mechanically ventilated with one ventilator, as might be considered during a shortage of ventilators (such as during a
pandemic). Even for two individuals well matched for weight and height (and thus appropriate tidal volume), differences in lung mechanics such as resistance and compliance (particularly due to underlying
ARDS) may lead to pendelluft between the two patients in the circuit. Despite this and many other limitations, ventilation of two patients simultaneously was considered and trialled during the
COVID-19 pandemic, however was not used widely. == References ==