Sonographic predictors of dyspnea relief after therapeutic thoracentesis – a prospective study

<bold>Background and objectives:</bold> Breathlessness is the most frequent symptom in pleural effusion (PE). The study aimed to evaluate the ability of pre-procedure pleural and diaphragm ultrasound (US) assessments to predict improvement in dyspnea scores post-procedure in patients with PE undergoing large-volume thoracentesis. <bold>Methods:</bold> The study recruited symptomatic patients with moderate to large PE undergoing large-volume thoracentesis. Pre drainage US assessment of pleural fluid (size, side& septations), displacement of collapsed lung at breath-hold & diaphragm (excursion, direction of movement & shape) was done. Dyspnea assessment was done using 100 mm visual analogue scale (VAS) immediately before and 4-24 hours after thoracentesis. Responders were those who achieved the minimal clinically important difference in VAS (19 mm). <bold>Results:</bold> The study included 32 patients (mean age 59.5±10.5, 56% males). PEs were right sided in 66% with mean maximum depth 13.4±2.8 cm, and 75% were non septated. Median diaphragm excursion was 1.57 [1.2-2.45] cm and 75% showed paradoxical diaphragm movement. Mean lung displacement was 0.31±0.13 cm. 23/32 (68%) of the patients had symptomatic response. Mean VAS before drainage was 64±16 mm and after drainage 40±21. Responders had larger effusions (mean depth 14.2 vs 11.1 cm, p=0.003), and were more likely to have paradoxical diaphragm movement (79% vs 50%, p=0.11). Other parameters did not differ significantly according to response. <bold>Conclusion:</bold> Apart from effusion size and diaphragm movement, no US parameter correlated with relief of dyspnea. Recruitment to the study is ongoing and final results will be available at the congress.