SESSION TITLE: Asthma - Bronchiectasis Posters
SESSION TYPE: Original Investigation Poster
PRESENTED ON: Wednesday, October 28, 2015 at 01:30 PM - 02:30 PM
PURPOSE: FEV1 reversibility has been the gold standard for demonstrating reversible obstruction in asthma. However, lung volume reversibility has not been formally tested in asthma. Therefore, we investigated lung volume and spirometry indices following bronchodilator administration in asthma.
METHODS: Adults with symptomatic asthma for >12 months were prospectively recruited into Lung Volume Assessment in Asthma Study (LUVA) if they met inclusion criteria. A questionnaire was administered before and after administration of 400ug of Albuterol as per ATS recommendation. Paired t test was used to compare pre and post test change. Correlation was checked using Pearson’s coefficient. Post-test mean residual volume was 7.6%+13.9. Therefore, post-test residual volume increasing by at least 9.6% was considered a significant reversibility.
RESULTS: Of the 91 subjects, 76% were female. The mean age was 52 ± 14 years. The ethnicity was Caucasian 58%, Hispanics 23%, African Americans 12% and others were 7%. Eight subjects were current smokers. The median-asthma duration was 16 ± 16 years. All spirometry and lung volumes improved significantly following bronchodilator (all p<0.01). Residual Volume (RV) reversibility value was normally distributed compared to FEV1 reversibility value. While RV showed a modest correlation (r=0.2, p=0.01) to severity of wheeze, there was no correlation between FEV1(r=0.009, p=0.93) and wheeze. The mean improvement in RV value was 7.6% ± 13.9 and FEV1 was 10.3% ±13.5. There was a minimal correlation between FEV1 reversibility and RV reversibility (R2=0.13). A significant FEV-1 reversibility was observed in 25%, but a significant RV reversibility was seen in 46%.
CONCLUSIONS: Increased RV seems to explain severity of symptoms better than low FEV1. RV reversibility improves the diagnosis of reversible obstruction in asthma. RV reversibility should be checked in addition to FEV1 reversibility in the diagnosis and management of asthma.
CLINICAL IMPLICATIONS: RV reversibility improves the yield of reversible obstruction and may reduce the need for provocation test. Current recruitment criteria of subjects to clinical trials based on FEV1 reversibility alone needs revision.
DISCLOSURE: The following authors have nothing to disclose: Ali Rashidian, Sasan Sazgar, Janil Mejia, Tim Tyner, Belayneh Abejie, Vipul Jain, Jose Vempilly
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