Pulmonary Function Testing: Flow Volume Loop Patterns

 • Variable extra-thoracic obstruction - truncated or flattened inspiratory flow & reduced FEF50/FIF50

 • Variable intra-thoracic obstruction - truncation or flattening of the expiratory flow

 • Fixed obstruction - truncation or flattening of both the inspiratory and expiratory flows and an increase in FEF50/FIF50 ratio

 • Early airflow obstruction - concave upward or “scooped out” expiratory flow with decreased FEF25-75% and persevered FEV1

 • Airflow obstruction - concave upward or “scooped out” expiratory flow with reduced FEV1

 • Restriction



- Nick Mark MD @nickmmark





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