SESSION TITLE: Physiology/PFTs/Rehabilitation Posters
SESSION TYPE: Original Investigation Poster
PRESENTED ON: Wednesday, October 30, 2013 at 01:30 PM - 02:30 PM
PURPOSE: To establish whether obesity, as determined by body mass index (BMI) is associated with abnormal pulmonary function test (PFT) values, specifically diffusing capacity (DLCO).
METHODS: This is a retrospective study of obese patients (BMI>30) who underwent a PFT in 2010 for pulmonary symptoms or pre-op evaluation for gastric bypass. Patients were excluded if they had a known history of underlying lung disease or had abnormal imaging suggesting the presence of a structural lung disease. Data included age, height, weight, calculated BMI, spirometry, full lung volumes and DLCO. We used Pearson correlations with scatter plots and best-fit lines for the comparisons between BMI and PFT variables.
RESULTS: 244 patients were included with an average BMI of 40.39 (range 30 - 82.13). The only statistically significant correlation identified was between BMI and the expiratory reserve volume (ERV) (-0.253, p=0.0005), which demonstrated an inverse correlation. There was a trend toward abnormal DLCO and higher BMI (-0.084, p=0.192), but it was not significant. There was no correlation between BMI and forced vital capacity (FVC) (0.021, p=0.742).
CONCLUSIONS: There was no significant correlation found between BMI and DLCO or FVC, although a trend was noted for abnormal DLCO with increasing BMI. However, ERV was noted to be inversely proportional to BMI in obese patients.
CLINICAL IMPLICATIONS: Low ERV in obese patients implies a decrease in the area available for gas exchange and therefore may result in more hypoxemia. BMI does not reflect distribution of fat and is a less sensitive indicator of effect on pulmonary function than indices that do reflect fat distribution (i.e. waist-hip ratio). ERV is a readily available measure of the clinical significance of obesity in patients with BMI > 30 who report dyspnea or who are found to have hypoxemia.
DISCLOSURE: The following authors have nothing to disclose: Elizabeth Awerbuch, Charles Peng, Huma Aslam, Patricia Villamena, Albert Miller
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