Comparative Performance of Pulmonary Ultrasound, Chest Radiograph, and CT Among Patients With Acute Respiratory Failure*

Objectives: The study goal was to concurrently evaluate agreement of a 9-point pulmonary ultrasound protocol and portable chest radiograph with chest CT for localization of pathology to the correct lung and also to specific anatomic lobes among a diverse group of intubated patients with acute respiratory failure. Design: Prospective cohort study. Setting: Medical, surgical, and neurologic ICUs at a 670-bed urban teaching hospital. Patients: Intubated adults with acute respiratory failure having chest CT and portable chest radiograph performed within 24 hours of intubation. Interventions: A 9-point pulmonary ultrasound examination performed at the time of intubation. Measurements and Main Results: Sixty-seven patients had pulmonary ultrasound, portable chest radiograph, and chest CT performed within 24 hours of intubation. Overall agreement of pulmonary ultrasound and portable chest radiograph findings with correlating lobe ("lobe-specific" agreement) on CT was 87% versus 62% (p < 0.001), respectively. Relaxing the agreement definition to a matching CT finding being present anywhere within the correct lung ("lung-specific" agreement), not necessarily the specific mapped lobe, showed improved agreement for both pulmonary ultrasound and portable chest radiograph respectively (right lung: 92.5% vs 65.7%; p < 0.001 and left lung: 83.6% vs 71.6%; p = 0.097). The highest lobe-specific agreement was for the finding of atelectasis/consolidation for both pulmonary ultrasound and portable chest radiograph (96% and 73%, respectively). The lowest lobe-specific agreement for pulmonary ultrasound was normal lung (79%) and interstitial process for portable chest radiograph (29%). Lobe-specific agreement differed most between pulmonary ultrasound and portable chest radiograph for interstitial findings (86% vs 29%, respectively). Pulmonary ultrasound had the lowest agreement with CT for findings in the left lower lobe (82.1%). Pleural effusion agreement also differed between pulmonary ultrasound and portable chest radiograph (right: 99% vs 87%; p = 0.009 and left: 99% vs 85%; p = 0.004). Conclusions: A clinical, 9-point pulmonary ultrasound protocol strongly agreed with specific CT findings when analyzed by both lung- and lobe-specific location among a diverse population of mechanically ventilated patients with acute respiratory failure; in this regard, pulmonary ultrasound significantly outperformed portable chest radiograph.