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

Abstract

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 = À0.676, 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.

A virtual patient in interpretation of massive pleural effusion impact on hemidiaphragm work and an insignificant influence on blood oxygenation

“…3a shows such a case) because the contralateral hemidiaphragm affects also the ipsilateral lung through the compliant mediastinum. It might be enhanced in patients with contralateral hemidiaphragm hyperactivity 24 .…”

“…As a consequence, the amplitude of breathing-related P pl changes in the contralateral hemithorax must be much greater than normal to preserve the required V T . Thus, compensatory hyperactivity of this hemidiaphragm can be observed 24 . In addition, if the mediastinum is very compliant, then these large changes may propagate to the ipsilateral hemithorax, leading to the P-V loop that is leaned to the right but with great P pl variation.…”

Imaging of pleural disease

“…Based on the findings regarding diaphragm function in the PLEASE-1 study, the researchers initiated an investigation to examine the impact of pleural effusion on the function of both hemidiaphragms. Data from the pilot PLEASE-2 study suggest that unilateral pleural effusions affect the function of both hemidiaphragms [ 83 ]. Moreover, it has been noted that the abnormal function of the ipsilateral and contralateral of both hemidiaphragms resolved post-drainage.…”

Breathlessness with Pleural Effusion: What Do We Know?

“…Pleural fluid drainage reduces the distortion of ipsilateral hemidiaphragm shape and increases its excursion, and this appears to reduce excessive respiratory drive and compensatory increases in excursion of the contralateral hemidiaphragm. 37 Abnormalities in diaphragm movement are common in patients with pleural effusion, and their presence, in addition to baseline level of breathlessness, are independent predictors of likelihood of symptom relief after fluid drainage. 6…”

“…The PLEASE study findings 6,37 have provided a basis for detailed studies of diaphragm function and ventilatory drive in patients with symptomatic pleural effusion. Further work needs to be done to improve use of the PROMs to measure breathlessness in clinical trials, particularly optimizing frequency, and duration of measurement, what time period or event patients should be considering when assessing breathlessness and whether breathlessness should be assessed following a standardized activity.…”