Original ContributionEvaluation of lung ultrasound for the diagnosis of pneumonia in the ED
Introduction
Community-acquired pneumonia (CAP) in adults is a common disorder, potentially life threatening [1], with a high hospitalization rate [2]. It is the only acute respiratory tract infection in which delayed antibiotic therapy has been associated with increased risk of death [3]. Therefore, a correct and rapid diagnosis is mandatory.
Currently, chest radiograph (CXR) is recommended for the routine evaluation of a patient suspected of having pneumonia because medical history and physical examination cannot provide certainty in this diagnosis [4]. However, especially in the emergency department (ED) setting, CXR might have many limitations due to patient conditions, waste of time, and interobserver variability in its interpretation [5].
Computed tomography (CT), on the other hand, is considered to be the gold standard technique, but it is often not available, has high radiation dose, and has high cost [6].
Lungs are traditionally considered poorly accessible to ultrasound (US) investigation because of their air content [7]. Only in the last decade, it has been shown that the US assessment of the lung could have a role in common clinical practice [8].
In lung consolidations, air is replaced by fluid, leading to a good US transmission if there is a direct contact of the lesion with pleural surface [9], [10]. Not many studies were performed in the last years for the evaluation of lung US in the diagnosis of infectious lung diseases [11], [12], [13], [14], [15].
The aim of this study is to assess the ability of bedside lung US to confirm clinical suspicion of pneumonia and the feasibility of its integration in common ED clinical practice.
Section snippets
Setting
The study was conducted in the ED of S. Antonio Abate Hospital, Tolmezzo, Italy, a second-level general hospital, during a 4-month period (from October 4, 2006, to January 15, 2007). This ED usually has about 20 000 visits per year.
Inclusion criteria
Patients not consecutively admitted to our ED with signs and symptoms of CAP were studied. According to the international guidelines [16], [17], [18], [19], the suggestive clinical elements were cough, fever or dyspnea, sputum production, and pleuritic chest pain. In
Results
We studied 49 patients: 18 (36.7%) females and 31 (63.2%) males with a mean age of 60.9 years (SD, 21.8). Positive CXR or CT scan and indirectly the 10 days clinical follow-up confirmed pneumonia in 32 cases (65.3%). In this group, we had 31 (96.9%) positive lung US and 24 (75%) positive CXR (Table 1). Follow-up was always consistent with the diagnosis, showing an improved clinical picture (no fever, cough, or dyspnea) and a drop in inflammatory laboratory indexes such as C-reactive protein.
Discussion
In the present study, the use of CT to clarify contrasting results between lung US and CXR was crucial: if we had considered CXR as the gold standard, we would have had 8 false-positive echographic results (25% of 32 confirmed diagnoses), actually proven to be pneumonia. One of these cases is shown in Fig. 4. This was not caused only by patients' conditions hindering good CXR images: 3 of these patients, as said before, had a double-view CXR. Besides, the 8 negative CXRs were evaluated by a
References (27)
Community-acquired pneumonia
Lancet
(2003)- et al.
Interobserver reliability of the chest radiograph in community-acquired pneumonia. PORT Investigators
Chest
(1996) Real-time chest ultrasonography: a comprehensive review for the pulmonologist
Chest
(2002)Thoraxsonography—part II: peripheral pulmonary consolidation
Ultrasound Med Biol
(1997)- et al.
Ultrasound imaging of pneumonia
Ultrasound Med Biol
(1995) Sonographic diagnosis of pneumonia and brinchopneumonia
Eur J Ultrasound
(1996)- et al.
Bedside lung ultrasound in the assessment of alveolar interstitial syndrome
Am J Em Med
(2006) - et al.
Sonography of lung and pleura in pulmonary embolism: sonomorphologic characterization and comparison with spiral CT scanning
Chest
(2001) - et al.
Thoracic ultrasound for diagnosing pulmonary embolism: a prospective multicenter study of 352 patients
Chest
(2005) - et al.
Epidemiology of community-acquired pneumonia in adults: a population-based study
Eur Respir J
(2000)
Quality of care, process, and outcomes in elderly patients with pneumonia
JAMA
Testing strategies in the initial management of patients with community-acquired pneumonia
Ann Intern Med
High-resolution computed tomography for the diagnosis of community-acquired pneumonia
Clin Infect Dis
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