Diagnostic Use of Lung Ultrasound for Suspected Pneumonia in Nepal

This study is designed to evaluate the use of lung ultrasound compared to chest x-ray to diagnose pneumonia in Nepal. Given the ease, portability, and relative ease of teaching ultrasound, this would be potential technology available for many clinicians throughout Nepal to use for adult and pediatric patients presenting with suspected pneumonia. This would be especially useful in remote areas where clinicians have limited access to x-rays. Despite its utility, use of ultrasound to diagnose pneumonia in resource-limited settings like Nepal has not yet been studied. Therefore, this study is designed as a prospective, clinical diagnostic study to evaluate patients presenting with suspected pneumonia using diagnostic imaging of beside ultrasound compared with chest x-ray using computed tomography as the gold standard for diagnosis of pneumonia.

Study Design: A prospective, convenience sample of participants presenting with suspected pneumonia when trained ultrasound investigator is present in the Patan Hospital Emergency Department will be performed in Patan, Nepal. This study will be done in partnership with Patan Hospital Emergency Department and with the approval of Nepal Health Research Council and Patan Hospital's ethical review committee. Study Setting: Located in the Kathmandu valley, Patan Hospital is a large urban hospital with 35-bed Emergency Department that sees approximately 32,000 patients per year. Study Protocol: Prior to the enrolling patients, investigators in the Emergency Department will save lung ultrasound exams and interpret the exams. These exams will then be independently reviewed by an ultrasonographer to ensure adequate skill in lung ultrasonography. A kappa analysis of these scans will be performed. If kappa <0.6, we will review lung ultrasound with these investigators and repeat above evaluation until kappa of 0.6 is achieved. For participants meeting inclusion criteria, consent will be obtained from the participant. Consent will include explanation of use of bedside ultrasound and chest CT scan for diagnosis of their condition. This consent will also include explanation of risks and benefits in Nepali. These examinations will be provided free of charge to the participant. The investigator will record patient demographics, symptoms, lung exam findings, and pre-test probability of pneumonia (low, intermediate, high) on the data form. After initial clinical evaluation, a bedside lung ultrasound will be performed. A Sonosite M Turbo (Fujifilm Sonosite, Inc.) ultrasound machine will be used. The ultrasound examination will include ten views, two anterior views, two lateral views (one including the costophrenic angle), and one posterior view on both chest walls. The investigator will then record findings and diagnosis on the data entry form along with their post-test probability of pneumonia (low, intermediate, high). Participants will get a chest x-ray as a part of the standard evaluation. These readings will be recorded on the data sheet. Participants will then undergo a chest computed tomography (CT), as the diagnostic standard to evaluate for pneumonia. The chest x-ray and chest CT will be read by a radiologist. The radiologist will be blinded to the results of the previous studies. The reading and diagnosis according to CT will be recorded on the data form. Statistical Analysis The performance of ultrasound for diagnosis of pneumonia will be expressed as sensitivity, specificity, and likelihood ratios. Since the sensitivity of ultrasound is estimated around 90%, in order to detect a 20% difference based on a CXR sensitivity of 70%, 62 patients will be needed. McNemar's test will be used to evaluate any statistical difference in sensitivity between CXR and US.

All patients will initially get an ultrasound (interpreted by emergency department physician) followed by chest x-ray (read by independent radiologist) and computed tomography (read by radiologist)

Sensitivity and specificity of ultrasound compared to chest x-ray for the diagnosis of pneumonia using Chest CT as the gold standard for diagnosis.

Inclusion Criteria: Patients presenting to the Emergency Department at Patan Hospital age 18 or older with suspected signs of pneumonia with at least three of the following: temperature greater than 38 or history of fever, cough, dyspnea, heart rate higher than 100 beats per minute, or oxygen saturation lower than 92%. Exclusion Criteria: Children will be excluded from the study. Also, ultrasound studies completed by physicians not trained in lung ultrasound will not be included.

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