Early recognition of the 2009 pandemic influenza A (H1N1) pneumonia by chest ultrasound.
Crit Care. 2012 Feb 17;16(1):R30
Authors: Testa A, Soldati G, Copetti R, Giannuzzi R, Portale G, Gentiloni-Silveri N
Abstract
ABSTRACT: INTRODUCTION: The clinical picture of the pandemic influenza A (H1N1)v ranges from a self-limiting afebrile infection to a rapidly progressive pneumonia. Prompt diagnosis and well-timed treatment are recommended. Chest radiography (CRx) often fails to detect the early interstitial stage. The aim of this study was to evaluate the role of bedside chest ultrasonography (US) in the early management of 2009 influenza A (H1N1)v infection. METHODS: 98 patients who addressed to the Emergency Department complaining influenza-like symptoms were enrolled in the study. Patients not displaying symptoms of acute respiratory distress were discharged without further investigations. Among patients with clinical suspect of a community-acquired pneumonia, cases encountering other diagnosis or comorbidities were excluded from the study. Clinical history, laboratory tests, chest Rx, CT scan if indicated, contributed to define the diagnosis of pneumonia in remaining patients. Chest US was performed by an emergency physician, looking for presence of interstitial syndrome, alveolar consolidation, pleural line abnormalities and pleural effusion, in 34 patients with a final diagnosis of pneumonia, 16 having normal initial CRx, and in 33 without pneumonia, as controls. RESULTS: Chest US was carried out without discomfort in all subjects, requiring a relatively short time (9 minutes, range 7-13). An abnormal US pattern was detected in 32/34 patients with pneumonia (94.1%). A prevalent US pattern of interstitial syndrome was depicted in 15/16 patients with normal initial CRx, of whom 10 (62.5%) encountering a final diagnosis of viral (H1N1) pneumonia. Patients with pneumonia and abnormal initial CRx, of whom only 4 having a final diagnosis of viral (H1N1) pneumonia (22,2 %, P<0.05), mainly displayed an US pattern of alveolar consolidation. Finally, a positive US pattern of interstitial syndrome was found in 5/33 controls (15.1%). False negatives were 2/34 cases (5.9%) and false positives 5/33 (15.1%), with sensitivity of 94.1%, specificity 84.8%, positive predictive value 86.5% and negative predictive value 93.3%. CONCLUSIONS: Bedside chest US represents an effective tool for diagnosing pneumonia in Emergency Department. Also, it can accurately provide early stage detection of patients with (H1N1)v pneumonia having an initial normal CRx. Its routine integration into their clinical management is proposed.
PMID: 22340202 [PubMed - as supplied by publisher]