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Volume 21 Supplement 1

London Trauma Conference 2012

  • Meeting abstract
  • Open Access

The intrapleural volume threshold for ultrasound detection of pneumothoraxes

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Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine201321 (Suppl 1) :S4

  • Published:


  • Trauma Patient
  • Pneumothorax
  • Threshold Volume
  • Positive Pressure Ventilation
  • Chest Trauma


Small pneumothoraxes (PTXs) may not impart an immediate threat to trauma patients after chest injuries. However, if these patients require positive pressure ventilation even a small amount of pleural air may be relevant. Point-of-care lung ultrasonography (US) is a reliable tool in the diagnosis of PTX, but the performance characteristics regarding detection of miniscule PTXs needs to be defined. We aimed at finding the volume threshold of intrapleural air where PTXs confidently can be diagnosed.


Air was insufflated into a unilateral pleural catheter in seven incremental steps (10, 25, 50, 100, 200, 350 and 500 mL) in twenty intubated porcine models, followed by a diagnostic evaluation with US and a supine anteroposterior chest radiograph (CXR). The sonographers continued the US scanning until the PTXs could be ruled in, based on identification of the US sign “lung point”. The corresponding threshold volume was noted. A senior radiologist interpreted the CXRs images.


The mean threshold volume to detect miniscule PTXs using US was 17.8 mL ± 12.8 mL, range 10 mL to 50 mL. Sixty-five % of the PTXs were diagnosed at 10 mL, 25% at 25 mL and the last 10 % at 50 mL of intrapleural air. The radiologist correctly diagnosed 266 lungs (71.1%), had 93 false negative and 15 false positive interpretations. The sensitivity was 31.1% and the specificity 93.8%; the 95% confidence intervals were (22.6, 38.7) and (89.7, 96.4), respectively.


Miniscule PTXs could be diagnosed with a high level of accuracy using lung US; thus recommended performed by clinicians treating chest trauma patients when PTX is among the differential diagnoses.







Chest radiography


Computed tomography

Authors’ Affiliations

Department of Research and Development, Norwegian Air Ambulance Foundation, Droebak, Norway
Department of Anaesthesiology and Intensive Care, Stavanger University Hospital, Stavanger, Norway
Department of Surgical Sciences, University of Bergen, Bergen, Norway
Department of Radiology, Stavanger University Hospital, Stavanger, Norway
Faculty of Health Sciences, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
Department of Anaesthesiology and Intensive Care, Aarhus University Hospital, Aarhus, Denmark


© Oveland et al; licensee BioMed Central Ltd. 2013

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.