Diagnosis of pleural effusion by portable ultrasound and chest radiography in intensive care unit

Pleural effusion (PE) is common among ICU and acutely ill patients. Traditionally plain chest radiography (CXR) has been done for pleural effusion evaluation in ICU. However، better results have been reported by ultrasound for the diagnosis of this condition in ICU. In this study، we compared two methods of ultrasound and CXR in PE detection in ICU patients. Also we studied the percentage of thoracentesis by physician after detection of PE by ultrasonography or CXR. Portable supine CXR and chest ultrasound were done in Thirty-nine non-surgical patients who were admitted to the Medical and General ICUs of Imam Khomeini hospital in Tehran from Oct 2013 to Mar 2014. Ultrasound was done and interpreted by radiologist and CXR by patient'' physician. Thoracentesis or CT-scan was used as gold standard for PE diagnosis. Ultrasound in 29 patients (74. 3%) showed PE. In 21 patients thoracentesis was done by patient’s physician and all had PE with mean volume of 447. 2 (417. 6). In 13 of 18 patients without thoracentesis chest CT scan was available. It shows PE in 6 cases (all with positive PE in ultrasonography). CXR in 9 patients (23. 1%) was positive for PE and in 30 patients (76. 9%) was negative. The ability of chest ultrasound and CXR for diagnosis of PE was significantly different (P= 0. 0. 1). In 68. 9 % of cases that ultrasound was positive، the CXR was negative and only in 34. 5% of cases both methods had negative results. The sensitivity، specificity، positive and negative predictive values were 100% (87. 1-100)، 100% (58. 9-100)، 100% (87. 1-100)، 100% (58. 9-100) respectively for ultrasonography. For CXR there were 33% (16. 6-54. 0)، 100% (58. 9-100)، 100% (66. 2-100)، 28% (12. 1-49. 4) respectively. Ultrasonography for diagnosis of pleural effusion in ICU patients has better diagnostic performance than portable CXR