Post-thoracentesis Ultrasound Vs. Chest X-ray for the Evaluation of Effusion Evacuation and Lung Re-expansion: A Multicenter Study
Recommended Citation
Ratwani AP, Grosu H, Husnain SU, Sanchez T, Yermakhanova G, Pannu JK, Debiane LG, Depew ZS, Yarmus LB, Maldonado F, Lentz RJ, Rickman OB, Feller-Kopman DJ, Arai M, New H, Chen H, Chen S, Ost DE, Dana F, Rezai-Ghara L, Parker M, Lee P, Khemasuwan D, Shepherd RW, Rahman N, Shojaee S. Post-thoracentesis Ultrasound Vs. Chest X-ray for the Evaluation of Effusion Evacuation and Lung Re-expansion: A Multicenter Study. Am J Respir Crit Care Med 2024; 209(9):A3082.
Document Type
Conference Proceeding
Publication Date
5-21-2024
Publication Title
Am J Respir Crit Care Med
Abstract
Rationale: The utility of ultrasound examination as a follow-up imaging modality to thoracentesis, compared to traditional chest radiography (CXR), has not been thoroughly studied. Ultrasound is shown to have comparable sensitivity to CXR for the diagnosis of pneumothorax. However, CXR is still routinely obtained, in part to assess the degree of lung-parietal pleura apposition as an indicator of successful pleural space evacuation and lung re-expansion. Our study explores whether post-thoracentesis ultrasound is comparable to CXR in determining successful evacuation of the pleural space. Methods: Patients with free-flowing pleural effusions with minimal to no septations were recruited from six academic centers. Post-thoracentesis ultrasound was performed immediately following thoracentesis, and CXRs were obtained within 4-hours post-procedure. Our primary outcome was the agreement between US and CXR in their ability to assess complete pleural space evacuation. Complete pleural space evacuation was defined as the absence of pleural fluid on three ultrasound views (anterior, mid-axillary, and posterior) and minimal to no costophrenic angle blunting (CPA) on CXR (portable or PA/lateral technique). Residual postprocedure effusions were categorized as 'small' or 'large' based on pre-specified imaging criteria. Interobserver reliability was assessed through independent image reviews by two pulmonologists and two radiologists blinded to all patient/procedure data, with disagreements resolved by a third reviewer. Concordance of ultrasound-guided vs CXR-guided assessment of lung expandability was the secondary endpoint. In scenarios when most outcomes were categorized as 'present' in an imbalanced contingency table, the Kappa statistic was replaced with Gwet's AC1. Results: From February 2021 to May 2022, 147 patients were recruited for the study. Malignancy was the most frequent effusion etiology (n=49), followed by hepatic hydrothorax (n=22) and heart failure (n=11), and the pleural space was considered non-expandable in 50% of cases. A total of 823 pleural ultrasound images were collected for blind review. The Gwet's AC1 assessing complete pleural evacuation agreement between ultrasound and CXR was 0.93 (95% CI: 0.83-1.00). When assessing US vs. CXR agreement in relation to effusion size, a Cohan's Kappa of 0.64 (95% CI: 0.51-0.77) was observed. Ultrasound vs CXR-guided assessment of expandability showed a Cohan's Kappa of 0.89 (95% CI 0.81 to 0.96). Conclusion: Ultrasound use reduces the risk of radiation exposure and is routinely used before thoracentesis. Our findings show that postthoracentesis ultrasound can be considered an equally effective alternative to CXR when assessing clinically meaningful parameters such as pleural space drainage and lung expansion in noncomplicated pleural effusions.
Volume
209
Issue
9
First Page
A3082
