EMReports | The Stratosphere or Barcode Sign

The Stratosphere or Barcode Sign

Larry Mellick, MD, MS, FAAP, FACEP
Professor of Emergency Medicine and Pediatrics
Medical College of Georgia

Pearl: What do you get when a 1200 pound horse bucks you off, rears over you, and lands his front hooves on your chest? What you get are bruises, broken ribs, pneumothorax, hemothorax, and a positive stratosphere sign on your lung ultrasound.

Presentation: This 57-year-old man presented to the emergency department on a back board with C-spine immobilization. He was in severe pain from injuries sustained to his anterior chest. He reported that he had been bucked off the back of a new horse, and the horse had reared over him and landed both front hoofs on his chest. (Figure 1) The patient reported that his ribs were broken because he felt them moving with each breath.

The patient was admitted to the trauma service for management of the pain from his broken ribs and observation of his small pneumothorax and hemothorax. Ultrasound of his chest upon arrival showed findings consistent with a pneumothorax. We were unable to demonstrate the sliding lung sign and, on M-mode, the stratosphere sign was noted. These findings were confirmed with a CT scan that demonstrated a right pneumothorax with atelectasis and possible pulmonary contusion of the right lung. Fifth and sixth rib fractures and extensive subcutaneous air also were noted on the right. A minimal pneumomediastinum also was present. (Figure 2)

Discussion: Research in the late 1980s and early 1990s demonstrated that ultrasound could be used in the diagnosis of lung disease.^1,2 Subsequent work demonstrated that the ultrasound can diagnose pneumothorax accurately.^3,4,5 The stratosphere sign is seen when there is the absence of the sliding lung sign and the seashore sign. The sliding lung sign seen with two-dimensional ultrasound is a to-and-fro moving (with respirations) hyperechogenic line seen at the pleural line or where the chest wall (parietal) and lung pleural (visceral) surfaces interface.⁶ The sliding lung sign also may be absent in the presence of pleural adhesions, mainstem intubation, pulmonary contusion or infiltrate, ARDS and atelectasis. The seashore sign is seen using the ultrasound M-mode. This sign is evidence of a normal lung-chest wall interface and is best described as parallel lines corresponding to the static thoracic wall and a sandy pattern under the pleural line produced by the lung parenchyma. (Figure 3) The sandy pattern represents the shore and the parallel lines, the sea. Their border is the pleural lines. When this sign is replaced with the stratosphere sign, this is considered evidence for a pneumothorax.⁷ (Figure 4) The presence of air interposed between the chest wall and the lung results in pleural air that generates reverberation artifacts that form parallel horizontal echoic lines. The ultrasound image on M-mode has been described as having the appearance of the stratosphere or a barcode.

References:

Wernecke K, Galanski M, Peters PE, et al. Pneumothorax: Evaluation by ultrasound—preliminary results. J Thorac Imaging 1987;2:76 -78.
Targhetta R, Bourgeois JM, Chavagneux R, et al. Ultrasonic signs of pneumothorax: Preliminary work. J Clin Ultrasound 1993;21:245-250.
Blaivas M, Lyon M, Duggal S. A prospective comparison of supine chest radiography and bedside ultrasound for the diagnosis of traumatic pneumothorax. Acad Emerg Med 2005;12:844-849.
Soldati G, Testa A, Sher S, et al. Occult traumatic pneumothorax: diagnostic accuracy of lung ultrasonography in the emergency department. Chest 2008;133:204-211. Epub 2007 Oct 9.
Kirkpatrick AW, Sirois M, Laupland KB, et al. Hand-held thoracic sonography for detecting post-traumatic pneumothoraces: The Extended Focused Assessment with Sonography for Trauma (EFAST). J Trauma 2004;57:288-295.
Lichtenstein DA, Menu Y. A bedside ultrasound sign ruling out pneumothorax in the critically ill. Lung sliding. Chest 1995;108:1345-1348.
Lichtenstein D.A. Ultrasound in the management of thoracic disease. Crit Care Med 2007;35(5 Suppl):S250-S261.

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