Bronchial Effervescence: A Sonographic Sign of Bacterial Pneumonia?

Abstract

PURPOSE: Point-of-care ultrasound (POCUS) of the lung and pleura is increasingly incorporated as a useful diagnostic tool in the intensive care unit (ICU). It has been suggested to be superior to traditional chest x-ray (CXR) for the detection of pneumothorax, and has also been used to rule out atelectasis as a cause of consolidation. Bronchial effervescence (BE), the presence of discrete, mobile, hyperechoic "bubbles" of air within bronchi of consolidated lung, has been alluded to in the literature, but no formal descriptions of its implications have been made. METHODS: In our hospital, a tertiary care academic center, it is routine for patients with abnormal chest imaging to receive POCUS of the lungs for further classification. A convenience sample of 99 patients in the ICU received POCUS of the lungs. RESULTS: Of those, incidences of the following characteristics on ultrasound were noted: 69% (69/99) had consolidation, 72% (72/99) had pleural effusion, 58% (58/99) had sliding lung, and 3% (3/99) had BE. Of the 3 patients with BE, all were mechanically ventilated, had consolidation, pleural effusion, and sliding lung, as well as culture-proven bacterial pneumonia. Patient 1 was admitted with dyspnea and cough, found to have consolidation on computed tomography, and grew S. pneumoniae from both blood and sputum cultures. Patient 2 had endocarditis and bilateral consolidation evident on CXR with loss of the hemidiaphragm, and grew methicillin-resistant S. aureus from blood. Patient 3 presented with fever and cough, developed septic shock with left upper lobe consolidation on CXR, and grew K. pneumoniae from sputum. In this very small convenience sample, presence of BE was specific (3/3) for bacterial pneumonia, but present in but a small percentage of consolidation seen on ultrasound as whole (6%, 4/69). CONCLUSIONS: BE was exclusively seen in pneumonia and not other forms of consolidation in 99 lung ultrasounds. CLINICAL IMPLICATIONS: Given potential clinical utility of BE and small size of the sample here, further studies are warranted to better elucidate the diagnostic implications of this unique sonographic sign.