A bedside ultrasound sign ruling out pneumothorax in the critically ill. Lung sliding.

Abstract

STUDY OBJECTIVES: To describe and evaluate an ultrasound pattern useful in the diagnosis of pneumothorax. DESIGN: Ultrasound examination of "lung sliding," a respiratory movement visible when investigating the chest wall. SETTING: The medical ICU of a university-affiliated hospital. PATIENTS: The study group included 43 proved pneumothoraces, either by chest radiograph (n = 40) or by CT (n = 3). The control group included 68 hemithoraces in which the absence of pneumothorax was proved by CT. INTERVENTION: Analysis of anterior chest wall in supine patients. MEASUREMENTS AND RESULTS: Feasibility was 98.1%. Disappearance of "lung sliding" was observed in 100% of 41 analyzable cases of pneumothorax vs 8.8% of the hemithorax without pneumothorax (6 of 68). In this series, sensitivity was 95.3%, specificity 91.1%, and negative predictive value 100% (p < 0.001). CONCLUSIONS: Ultrasound was a sensitive test for detection of pneumothorax, although false-positive cases were noted. The principal value of this test was that it could immediately exclude anterior pneumothorax.