Chest
Clinical Investigations in Critical CareA Bedside Ultrasound Sign Ruling Out Pneumothorax in the Critically III: Lung Sliding
Section snippets
Methods
We have studied 43 pneumothoraces in 42 consecutive, critically ill patients: idiopathic (n=15), iatrogenic (n=11), complicated thoracic trauma (n=2), adult respiratory distress syndrome (ARDS) (n=10), or chronic lung disease (n=4). Average age was 42 years (range, 21 to 75 years). Seventeen patients (40.4%) developed pneumothorax while receiving mechanical ventilation.
We considered as a specific sign of pneumothorax a displacement of the visceral pleura from the parietal pleura by air within
Results
Investigation of the anterior lung/wall interface was possible in 109 of 111 hemithoraces: in two patients, pneumothorax was associated with parietal emphysema, and the lung/wall interface was not analyzable.
Anterior “lung sliding” was absent in 100% of the other 41 proved pneumothoraces, each time over an anterior area larger than three intercostal spaces. Anterior “lung sliding” was present in 91.1% of the hemithoraces in the control group, ie, 62 of 68. In six cases, it was absent without
Discussion
The lung is usually considered poorly accessible to ultrasound. Indeed, the ultrasound image is herein exclusively composed of artifacts, because air stops the progression of the ultrasound beam (Fig 1). The lung is, however, a vital organ. In our study, ultrasound was able to detect at least one elementary sign, probably due to the movement of the lung toward the abdomen during inspiration and vice versa.
The first description of the role of ultrasound in the diagnosis of pneumothorax was given
Conclusions
Ultrasound visualization of “lung sliding” was always correlated with the absence of pneumothorax. From this elementary sign alone, it was possible to exclude at least anterior pneumothorax, promptly and at the bedside of a mechanically ventilated patient. This was the major finding of this study.
The absence of “lung sliding” was suggestive, but not sufficient to affirm pneumothorax. Life-threatening pneumothorax in patients in the ICU is often extensive, with at least anterior involvement. In
Acknowledgments
We are grateful to David Marsh for his precious help in the elaboration and translation of this work. We thank Prof François Jardin for his advice. The CTs were recorded in the Department of Radiology of Prof. Pascal Lacombe, to whom we are grateful.
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