Original ContributionPerformance comparison of lung ultrasound and chest x-ray for the diagnosis of pneumonia in the ED☆
Introduction
Acute pneumonia is the first cause of mortality related to infectious disease in Western countries, and on major cause of severe sepsis and septic shock [1]. However the diagnosis of acute pneumonia is often difficult in the emergency setting, as clinical, biological, and imaging sign are not specific [2].
International guidelines recommend the use of chest x-ray as first line examination, despite its low sensitivity and specificity [3]. Thoracic computed tomography (CT) scan, although considered as the gold standard, is often not performed and involves an important exposure to ionizing radiations, limiting its use to difficult cases.
Lung ultrasounds have shown a growing interest during the last few years in the diagnosis of pleural effusions, pneumothorax, pneumonias, or pulmonary contusions [4], [5], [6]. Most studies were realized in patients from intensive care setting. The results are so encouraging that in some units, chest x-rays have been replaced by lung ultrasounds in the follow-up of the patients [7], [8]. In the emergency department (ED), the use of lung ultrasounds in the diagnosis of acute pneumonia has been studied in only a few studies [9]. Because of the bedside use of the ultrasound units, result can be immediately available preventing any delay in the diagnosis process. Moreover, its realization by the attending emergency physician could allow a substantial time-saving for the establishment of the diagnosis and consequently reduce the length of stay at the ED. However, the reliability of ultrasound diagnosis of acute pneumonia by ED physician must be confirmed before generalization of its use.
The aim of this study was to assess the potential of bedside lung ultrasound examination by the attending emergency physician in the diagnosis of acute pneumonia.
Section snippets
Material and methods
The study protocol has been approved by the local Ethics Committee of our institution (PV 27613).
In this single-center study, patients were included in the ED setting if presented the following criteria:
Age 18 years and older, suspected of infectious acute pneumonia with at least three of the following items: tympanic temperature equal or higher than 38°C, cough, dyspnea, heart rate higher than 100 beats per minute, saturation of oxygen lower or equal to 92% in ambient air.
Five emergency
Statistical analysis
Continuous variables were expressed as means ± SD and categorical data as numbers (percentages). The performance of each examination was expressed as sensitivity, specificity, positive and negative predictive values, and then compared by χ2 test.
A value of P < .05 was considered as a statistical significance. A population size calculation has been performed based on a preliminary study performed in our units, and found the need to include at least 120 patients to allow detection of a difference
Results
One hundred sixty-six patients were included from January 2010 to June 2012. Twenty-two patients were secondarily excluded, resulting in 144 finally analyzed patients. (Fig. 3)
The study population included 72 men and 72 women aged 77.6 ± 15.2 years. The diagnosis of pneumonia was retained after hospitalization for 123 of them. The respective diagnosis performances of lung ultrasound and chest x-ray, and their comparison are shown in Table 1.
Nine patients who were diagnosed with pneumonia after
Discussion
The present study is one of the first to show a potential interest for the lung ultrasound compared to standard care patients for the diagnosis of acute pneumonia in non-selected ED patients. This study reveals a significantly higher sensitivity of lung ultrasound for the diagnosis of acute pneumonia compared to chest X-ray (95% vs 60%, P < .01). Interestingly lung ultrasound appears to be particularly more effective than chest X-ray when pneumonia is evolving for less than 24 hours. Moreover,
Conclusion
This study shows a clear superiority of lung ultrasound performed by a trained ED physician over the chest x-rays for the diagnosis of acute pneumonia. Given the ultrasonography performance for the diagnosis of acute pneumonia, lung ultrasound could replace chest x-ray as the first-line imaging investigation. In difficult cases (deep lesion) or in case of negative ultrasound, thoracic CT scan could be performed as suggested by a proposed decision-making algorithm for acute pneumonia diagnosis
References (17)
Ultrasound imaging of pneumonia
Ultrasound Med Biol
(1995)Sonographic diagnosis of pneumonia and bronchopneumonia
Eur J Ultrasound
(1996)Chest wall and lung surface viewing with ultrasound
Chest
(1988)Agreement between lung ultrasonography and chest radiography in the intensive care unit
Ann Fr Anesth Reanim
(2011)Bedside lung ultrasound in the assessment of alveolar-interstitial syndrome
Am J Emerg Med
(2006)- et al.
Evaluation of lung ultrasound for the diagnosis of pneumonia in the ED
Am J Emerg Med
(2009) - et al.
Can chest ultrasonography replace standard chest radiography for evaluation of acute dyspnea in the ED?
Chest
(2011) - et al.
Relevance of lung ultrasound in the diagnosis of acute respiratory failure: the BLUE protocol
Chest
(2008)
Cited by (133)
Optimizing Diagnosis and Management of Community-acquired Pneumonia in the Emergency Department
2024, Emergency Medicine Clinics of North AmericaEpidemiological and clinical management aspects of pneumonias diagnosed in the emergency department in elderly patients in Spain: results of the EDEN-29 Study
2023, Enfermedades Infecciosas y Microbiologia ClinicaSerial Transthoracic Ultrasonography Studies in Hematopoietic Cell Transplant Patients: A Tool for Early Lung Pathology Detection
2023, Ultrasound in Medicine and BiologyCitation Excerpt :Radiation-free, point-of-care lung ultrasound (LUS) would allow screening and prospective monitoring for lung complications in hematological malignancy patients with the potential to decrease morbidity and mortality from pulmonary complications. LUS has been reported to be of greater sensitivity than physical examination or CXR, with an accuracy level comparable to that of CT scans for detecting pulmonary injuries (Via et al. 2012; Bourcier et al. 2014; Bouhemad et al. 2015). Studies on intensive care unit (ICU) and adult trauma patients using CT scans as the reference standard to evaluate the performance of LUS and CXR exams revealed LUS had higher accuracy, sensitivity and specificity for the main pathological features likely to be found in hematological malignancy patients (Via et al. 2012; Bourcier et al. 2014; Bouhemad et al. 2015).
POCUS in dyspnea, nontraumatic hypotension, and shock; a systematic review of existing evidence
2022, European Journal of Internal MedicineCitation Excerpt :The data are summarized in Table 1. Bourcier et al. [46] compared the diagnostic accuracies of CXR and POCUS in 144 patients with a suspected pneumonia. POCUS had a superior sensitivity.
The Rat Thoracic Ultrasound protocol: scanning technique and normal findings
2024, Frontiers in Veterinary Science
- ☆
Conflict of interest: The authors have no conflict of interest to disclose.