Platythorax increases residual volume/total lung capacity in idiopathic pleuroparenchymal fibroelastosis

Idiopathic pleuroparenchymal fibroelastosis (iPPFE) is a chronic progressive interstitial lung disease (ILD) characterized by upper lobe-dominant elastofibrosis [1]. Patients with iPPFE exhibit physical features such as emaciation, platythorax, and deepened suprasternal notch [1]. In most patients with restrictive lung disease, the vital capacity (VC), residual volume (RV), and total lung capacity (TLC) decrease proportionately without affecting the RV/TLC ratio [2, 3]. Pulmonary physiology in patients with iPPFE is notable due to the markedly decreased VC and increased RV/TLC ratio [1, 4–6]. This deviation from the typical pattern observed in most patients with restrictive lung diseases raises questions regarding the mechanism underlying increased RV/TLC ratio in patients with iPPFE. Researchers have postulated that platythorax and hyperinflation in the lower lobes are potential contributors to an increase in the RV/TLC ratio in patients with iPPFE [4, 6–11]. This study aimed to elucidate the mechanism underlying the increase in the RV/TLC ratio in patients with iPPFE. Footnotes This manuscript has recently been accepted for publication in the ERJ Open Research . It is published here in its accepted form prior to copyediting and typesetting by our production team. After these production processes are complete and the authors have approved the resulting proofs, the article will move to the latest issue of the ERJOR online. Please open or download the PDF to view this article. Conflicts of interest: The authors declare no conflicts of interest in association with the present study.