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

BACKGROUND AND OBJECTIVE: The pathophysiology of breathlessness in pleural effusion is unclear. In the PLEASE-1 study, abnormal ipsilateral hemidiaphragm shape and movement, assessed qualitatively, were independently associated with breathlessness relief after pleural drainage. Effects of pleural effusion on contralateral hemidiaphragm function are unknown. PLEASE-2, a prospective exploratory pilot study, assessed the effects of unilateral effusion and drainage on both hemidiaphragms using advanced quantitative bedside ultrasonography. METHODS: Individuals with symptomatic unilateral pleural effusion undergoing therapeutic drainage were included. Measurements pre- and post-drainage included severity of breathlessness (visual analogue scale) and ultrasound measurements of diaphragm excursion and thickness, in addition to shape and movement. Diaphragm measurements were compared to published reference values. RESULTS: Twenty participants were recruited (mean age 68.9 [SD 12.8] years, 12 females). During tidal breathing, contralateral hemidiaphragm excursion exceeded ipsilateral excursion and reference values (all p ≤ 0.001). Contralateral excursion was greatest in participants with abnormal ipsilateral hemidiaphragm movement and was inversely correlated with ipsilateral tidal excursion (r = -0.676, p = 0.001). Following drainage (mean volume 2121 [SD = 1206] ml), abnormal shape (n = 12) and paradoxical movement (n = 9) of the ipsilateral hemidiaphragm resolved in all participants, and tidal excursion of the contralateral hemidiaphragm normalized. Relief of breathlessness post-drainage correlated with improvement in ipsilateral hemidiaphragm excursion (r = 0.556, p = 0.031). CONCLUSION: This pilot study suggests, for the first time, that unilateral pleural effusion not only impairs ipsilateral hemidiaphragm function but also causes compensatory hyperactivity of the contralateral hemidiaphragm, which resolves post-drainage. These findings provide a basis for detailed studies of diaphragmatic function and ventilatory drive in patients with symptomatic pleural effusion.

The third PLeuralEffusion And Symptom Evaluation (PLEASE-3) study: Bendopnoea in patients with pleural effusion.

Background: Pleural effusions often cause disabling breathlessness, however the mechanism is unknown. Patients with pleural effusions are subjected to pleural fluid drainage on a 'trial and error' basis, as symptom relief varies. This population commonly complain of bendopnoea (breathlessness on bending forward) which has not been investigated. Our pilot data found bendopnoea was significantly associated with presence of pleural effusion. The PLEASE-3 study will evaluate bendopnoea as a screening test for effusion-related breathlessness, its predictive value of symptomatic benefits from fluid drainage and explore its underlying physiological mechanism. Methods: PLEASE-3 is a multi-centre prospective study. Eligible patients are assessed at baseline (pre-drainage) and for patients undergoing drainage, up to 72 h post-procedure. Outcome measures include the prevalence of bendopnoea, its correlation with size of effusion and its predictive value of breathlessness relief after drainage. The relationship of bendopnoea with breathlessness, physiological parameters, functional capacity and diaphragmatic characteristics will be assessed. The study will recruit 200 participants. Discussion: This is the first study to investigate bendopnoea in patients with pleural effusion. It has minimal exclusion criteria to ensure that the results are generalisable. The presence and clinical significance of bendopnoea in the context of pleural effusion requires thorough investigation. The post assessment of patients undergoing pleural fluid drainage will provide insight into whether the presence of bendopnoea is able to predict clinical outcomes. Trial Registration: Name of the registry: Australia New Zealand Clinical Trial Registry Trial registration number: ACTRN12622000465752. URL of the trial registry record for this trial: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=383639&isReview=true Date of registration: Registered on 24 March 2022. Funding of the trial: This study has received funding from the Sir Charles Gairdner Research Advisory Council research project grant. The study is sponsored by the Institute for Respiratory Health, a not-for-profit organisation. Name and contact information for the trial sponsor: Mr Bi Lam; Finance manager. Level 2, 6 Verdun Street, Nedlands WA 6009. t‖ + 61 8 6151 0877 e‖ bi.lam@resphealth.uwa.edu.au Role of sponsor : The funder is not involved in the planning of the study, gathering, analysing, and interpreting the data, or in preparing the manuscript.