Study objectives: There has been some discussion in the literature about using ultrasonography as an extension of the physical examination. This study attempts to determine which technique, physical examination or bedside thoracic ultrasonography, is more accurate in diagnosing pleural effusion. A 4-point real-time thoracic ultrasonograph was compared with traditional physical examination including auscultation with stethoscope, chest percussion, and tactile fremitus.

Methods: This was a prospective observational study of patients who presented to the emergency departments of MCP and Hahnemann University Hospitals between November 2003 and April 2004. Patients included in the study were adults who presented with a chief complaint of dyspnea with a history of congestive heart failure, malignancy, rheumatologic disease, or suspected pneumonia. Patients requiring intubation or who were otherwise unable to sit up for thoracic sonogram were excluded. Postgraduate year (PGY)-1 or PGY-2 emergency medicine residents performed a physical examination, and a separate PGY-2 emergency medicine resident performed a bedside thoracic ultrasonograph. The ultrasonographic residents had limited ultrasonography experience (<25 scans) and used a portable ultrasonographic machine (SonoSite 180plus). Both physicians were blinded to the results of the patient's chest radiograph and to each other. Both physicians recorded presence, location, and size (small <3 cm, moderate 3 to 10 cm, and large >10 cm) of effusion, and these results were compared to staff radiologist's interpretation of the chest radiograph.

Results: Thirty-seven patients were enrolled, 15 with pleural effusion on 1 or both sides and 22 without pleural effusion. Sensitivity trended toward being greater in the ultrasonography (80%; 95% confidence interval [CI] 57.5% to 81.4%) versus physical examination group (53%; 95% CI 31.6% to 72.2%, P=.09; odds ratio 2.9, 95% CI 0.69 to 17.7). There was no difference in specificity (71% for both groups).

Conclusion: Bedside thoracic ultrasonography appears to be more sensitive than traditional physical examination using a stethoscope in the detection of pleural effusion.