PT  - JOURNAL ARTICLE
AU  - Diaz-Guzman, Enrique
AU  - McCarthy, Kevin
AU  - Siu, Alan
AU  - Stoller, James K
TI  - Frequency and Causes of Combined Obstruction and Restriction Identified in Pulmonary Function Tests in Adults
DP  - 2010 Mar 01
TA  - Respiratory Care
PG  - 310--316
VI  - 55
IP  - 3
4099  - http://rc.rcjournal.com/content/55/3/310.short
4100  - http://rc.rcjournal.com/content/55/3/310.full
AB  - BACKGROUND: The frequency of combined obstruction and restriction identified in pulmonary function tests has not been well described. Moreover, although the causes of combined-obstruction-and-restriction patterns are known, the frequency of the various etiologies has received little attention. METHODS: We retrospectively reviewed medical records and surveyed pulmonologists. RESULTS: 43,212 PFT sessions were evaluated, which yielded 130 patients who satisfied our criteria for spirometry evidence of combined obstruction and restriction. Their demographic features were: mean ± SD age 54 ± 14 y, 51% male, mean ± SD body mass index 28.8 ± 6.7 kg/m2, mean ± SD height 174 ± 9 cm (men) and 162 ± 7 cm (women). The causes of combined obstruction and restriction were classified as either a pulmonary parenchymal disorder (Group A, n = 49, 38%) or a combination of pulmonary parenchymal and non-pulmonary diseases (Group B, n = 63, 48%). In 18 patients (14%) no clear etiology of combined obstruction and restriction could be determined. The most common pulmonary disease was chronic obstructive pulmonary disease (45/130, 35%), and the most common non-parenchymal disease was congestive heart failure (27/130, 21%). We electronically sent a survey to 55 pulmonary physicians, of whom 30 (55%) responded. The respondents estimated that combined obstruction and restriction occurs in approximately 20% of all the pulmonary function tests performed in their practices and that pulmonary parenchymal diseases were responsible for 35% of all instances of combined obstruction and restriction. CONCLUSIONS: Combined obstruction and restriction occurs infrequently and is more commonly caused by a combination of pulmonary parenchymal and non-pulmonary disorders. Pulmonologists' impressions regarding the frequency and causes are generally discordant with the observed frequencies.