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Prospective application of clinician-performed lung ultrasonography during the 2009 H1N1 influenza A pandemic: distinguishing viral from bacterial pneumonia

James W Tsung12*, David O Kessler4 and Vaishali P Shah3

Author Affiliations

1 Division of Pediatric Emergency Medicine, Departments of Pediatrics and Emergency Medicine, Bellevue Hospital Center/NYU School of Medicine, New York, 10016, USA

2 Departments of Emergency Medicine and Pediatrics, Mount Sinai School of Medicine, 1 Gustave Levy Place, New York, NY, 10029, USA

3 Department of Emergency Medicine, Childrens Hospital at Montefiore, Albert Einstein College of Medicine, Bronx, NY, 10467, USA

4 Department of Pediatrics, Columbia University College of Physicians and Surgeons, New York, NY, 10032, USA

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Critical Ultrasound Journal 2012, 4:16  doi:10.1186/2036-7902-4-16

Published: 10 July 2012



Emergency department visits quadrupled with the initial onset and surge during the 2009 H1N1 influenza pandemic in New York City from April to June 2009. This time period was unique in that >90% of the circulating virus was surveyed to be the novel 2009 H1N1 influenza A according to the New York City Department of Health. We describe our experience using lung ultrasound in a case series of patients with respiratory symptoms requiring chest X-ray during the initial onset and surge of the 2009 H1N1 influenza pandemic.


We describe a case series of patients from a prospective observational cohort study of lung ultrasound, enrolling patients requiring chest X-ray for suspected pneumonia that coincided with the onset and surge of the 2009 H1N1 influenza pandemic.


Twenty pandemic 2009 H1N1 influenza patients requiring chest X-ray were enrolled during this time period. Median age was 6.7 years. Lung ultrasound via modified Bedside Lung Ultrasound in Emergency protocol assisted in the identification of viral pneumonia (n = 15; 75%), viral pneumonia with superimposed bacterial pneumonia (n = 7; 35%), isolated bacterial pneumonia only (n = 1; 5%), and no findings of viral or bacterial pneumonia (n = 4; 20%) in this cohort of patients. Based on 54 observations, interobserver agreement for distinguishing viral from bacterial pneumonia using lung ultrasound was ΔΈ = 0.82 (0.63 to 0.99).


Lung ultrasound may be used to distinguish viral from bacterial pneumonia. Lung ultrasound may be useful during epidemics or pandemics of acute respiratory illnesses for rapid point-of-care triage and management of patients.

Ultrasound; H1N1 virus; Pneumonia; Emergency medicine; Point-of-care; Pandemic; Pediatric