flow-volume loop

Indications: 1) upper airway obstruction 2) chronic obstructive lung disease 3) reactive airway disease, i.e. asthma Procedure: - graphic displays of lung volume & airflow. Clinical significance: Characteristic patterns occur for certain respiratory disorders: 1) a plateau during forced inspiration is characteristic of extrathoracic upper airway obstruction (paradoxical vocal cord motion) 2) a plateau during forced expiration is characteristic of intrathoracic upper airway obstruction (tumor compressing trachea) 3) a plateau during both forced inspiration & expiration is characteristic of a fixed upper airway obstruction such as tracheal stenosis 2) low flow rates with minimal change with bronchodilation occur with chronic obstructive lung disease 3) low flow rates that improve with bronchodilation characterize reactive airway disease, i.e. asthma

General

pulmonary function test (PFT) loop

References

- Medical Knowledge Self Assessment Program (MKSAP) 11, 14, American College of Physicians, Philadelphia 1998. 2006