Ipsilateral and contralateral hemidiaphragm dynamics in symptomatic pleural effusion,the 2nd PLeural Effusion And Symptom Evaluation (PLEASE)-2 Study

Abstract

<b>Introduction:</b> Abnormal ipsilateral hemidiaphragm shape and movement are associated with dyspnoea relief post-thoracentesis&nbsp;(Murganandan S&nbsp;et al.&nbsp;ERJ 2020;55:1900980). Effusion effects on contralateral hemidiaphragm are unknown. This exploratory, pilot study assessed unilateral effusion and drainage effects on both hemidiaphragms using advanced ultrasound techniques. <b>Methods:</b> Individuals with symptomatic unilateral pleural effusion undergoing drainage were included. Severity of dyspnoea and ultrasound assessment of diaphragm excursion and thickness, shape and movement were recorded pre- and post-drainage. <b>Results:</b> Twenty participants were recruited (mean age 68.9 (SD 12.8) years, 12 female). On tidal breathing, contralateral hemidiaphragm excursion exceeded ipsilateral excursion and normal values (p≤0.001). Contralateral excursion was inversely correlated with ipsilateral excursion (r=-0.676,p=0.001) (Fig.1). Following drainage (mean volume 2121[SD=1206]mL), tidal excursion of the contralateral hemidiaphragm normalized. Relief of dyspnoea post-drainage correlated with improvement in ipsilateral hemidiaphragm excursion (r=0.556,p=0.031). <b>Conclusion:</b> This pilot study suggests that unilateral pleural effusion not only impairs ipsilateral hemidiaphragm function but also causes compensatory hyperactivity of the contralateral hemidiaphragm, which resolves post-drainage.