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Adjustment of the Severity of Obstruction in Patients with Mixed Obstructive Restrictive Pulmonary Function Testing

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Conference Paper

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59th Medical Wing San Antonio United States

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The interpretation of a pulmonary function test PFT can be challenging in patients with mixed obstructive and restrictive disorders, especiall in regards to the degree of obstruction. Prior studies identified the FEV1 overestimates the degree of obstruction because FEV1 is reduced from both the obstructive and restrictive components of the underlying disease. One smaller study adjusted the FRV1 for the decrease in TLC to better define the severity of underlying airway obstruction, which resulted in 83 of patients being changed to a less severe grade of obstruction according to ATSERS guidelines. This study aims to evaluate a larger population of patients with a mixed obstructive-restrictive pattern on full PFTs in or to correlate the grade of obstruction based on the degree of restriction and underlying lung disease. METHODS This study is a retrospective chart review of the PFT databases from multiple institutions. We selected individuals with both obstructive FEV1FVC less than lower limit of normal and restrictive TLC less than 80 lung disease. The severity of obstruction for unadjusted FEV1 predicted alone versus adjusted FEV1 predicted TLC predicted values were compared and reported according to ATSERS guidelines. Additional comparisons were made based on the degree of restriction less than 70 vs. less than 80 and cause of underlying lung disease COPD vs. other obstructive disease.

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  • Medicine and Medical Research

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