• Daphna Vilozni, Adi Dagan, Moran Lavie, Ifat Sarouk, Bat-El Bar-Aluma, Moshe Ashkenazi, Sarina Levy Mendelovich, Yael Betzalel, and Ori Efrati.
• Pediatric Pulmonary Unit, The National Center for Cystic Fibrosis, The Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Affiliated with the Sackler Faculty of Medicine, Tel-Aviv University, Israel. daphna.vilozni@sheba.health.gov.il.
• Respir Care. 2018 Aug 1; 63 (8): 981-987.

BackgroundInspiratory capacity (IC) is often overlooked as an important measured index of spirometry in patients with cystic fibrosis (CF). Abnormally low IC may indicate the onset of static/dynamic hyperinflation, which may be accompanied by dyspnea and an increase in the work of breathing. This cross-sectional study sought to determine whether measuring IC during spirometry, may add clinical value to FEV1 measurements in CF subjects.MethodsAnthropometric, clinical, spirometry, and static lung volume data were gathered retrospectively from 98 of 165 subjects with CF (mean ± SD age 26.8 ± 11.0 y) registered in The Edmond and Lily Safra Children's Hospital, Sheba Medical Centre, Israel. We compared the IC (% predicted) to FEV1, static lung volumes, and hospitalization days/year.ResultsIC decreased alongside FEV1 decline but at a slower pace (r2 = 0.32). Incremental trapped air, as measured by residual volume (RV), and a rapid elevation in the ratio of RV to total lung capacity occurred when IC deteriorated below 60% predicted values. The unique combination of IC < 50% predicted and FEV1 > 40% predicted induced an increase of up to 125 hospitalization days/year compared to subjects having IC > 50% predicted (up to 73 d/y, P < .001).ConclusionsMeasuring IC in CF subjects may reveal silent worsening of lung function as indicated by a decline in IC < 50% predicted while FEV1 is still > 40% predicted. This condition may lead to inefficient breathing at high lung volumes, which may explain a subjective sensation of breathlessness and lead to an increase in hospitalization days/year.Copyright © 2018 by Daedalus Enterprises.

24 keywords...

hide…