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Letter
Ultrasound performs better than radiographs
  1. Eustachio Agricola1,
  2. Charlotte Arbelot2,
  3. Michael Blaivas3,
  4. Belaid Bouhemad2,
  5. Roberto Copetti4,
  6. Anthony Dean5,
  7. Scott Dulchavsky6,
  8. Mahmoud Elbarbary7,
  9. Luna Gargani8,
  10. Richard Hoppmann9,
  11. Andrew W Kirkpatrick10,
  12. Daniel Lichtenstein11,
  13. Andrew Liteplo12,
  14. Gebhard Mathis13,
  15. Lawrence Melniker14,
  16. Luca Neri15,
  17. Vicki E Noble12,
  18. Tomislav Petrovic16,
  19. Angelika Reissig17,
  20. Jean Jacques Rouby2,
  21. Armin Seibel18,
  22. Gino Soldati19,
  23. Enrico Storti15,
  24. James W Tsung20,
  25. Gabriele Via21,
  26. Giovanni Volpicelli22
  1. 1San Raffaele Hospital, Milan, Italy
  2. 2Pitie Salpetriere Hospital, Pierre et Marie Curie University-Paris 6, France
  3. 3Northside Hospital Forsyth, Cumming, Georgia, USA
  4. 4Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
  5. 5University of Pennsylvania, Philedelphia, Pennsylvania, USA
  6. 6Henry Ford Hospital, Detroit, Michigan, USA
  7. 7King Saud University for Health Sciences, Riyadh, Saudi Arabia
  8. 8National Council of Research, Pisa, Italy
  9. 9University of South Carolina, Columbia, South Carolina, USA
  10. 10Regional Trauma Services, University of Calgary, Calgary, Alberta, Canada
  11. 11Paris-Ouest University, Paris, France
  12. 12Massachusetts General Hospital, Boston, Massachusetts, USA
  13. 13University of Innsbruck, Rankweil, Austria
  14. 14New York Methodist Hospital, Brooklyn, New York, USA
  15. 15Ospedale Niguarda Ca' Granda, Milan, Italy
  16. 16University PARIS XIII, Paris, France
  17. 17Friedrich Schiller University, Jena, Germany
  18. 18Diakonie Klinikum Jung-Stilling, Germany
  19. 19Valle del Serchio General Hospital, Lucca, Italy
  20. 20Mount Sinai Medical Center, New York, New York, USA
  21. 21Fondazione IRCCS Policlinico San Matteo, Pavia, Policlinico San Matteo, Pavia, Italy
  22. 22San Luigi Gonzaga University Hospital, Torino, Italy
  1. Correspondence to Andrew W Kirkpatrick, Regional Trauma Services, Foothills Medical Centre, 1403 29 St NW, Calgary, Alberta, T2N 2T9, Canada; andrew.kirkpatrick{at}albertahealthservices.ca

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We applaud the British Thoracic Society (BTS) for its efforts to improve patient care through scientific evidence. We thus recognise the recent guidelines on pleural procedures and thoracic ultrasound (TUS) as an important attempt to develop a rational approach to chest sonography.1 However, we are concerned that the BTS has reached conclusions based on a less complete review of TUS.

The guidelines state that ‘the utility of thoracic ultrasound for diagnosing a pneumothorax is limited in hospital practice due to the ready availability of chest x-rays (CXR) and conflicting data from published reports’.1 This conclusion appears to be based on a small (but landmark) study of 11 patients from 1986 to 1989, two small studies with only four pneumothoraces in one and another small series whose ultrasounds were retrospectively reviewed. Against these small and somewhat dated studies, a large number of recent investigations support a quite different conclusion.

Many well-performed retrospective reviews and a number of prospective studies have compared TUS to chest radiographs (CXR) in the detection of pneumothoraces using CXR as the criterion standard. Noting the limitations of CXR in detecting pneumothoraces, we feel that only prospective studies utilising CT as the reference criterion are valid to assess the relative merits of ultrasound versus radiography. Although methodology and populations have varied, at least nine comparative trials, conducted in the last decade, have noted a higher sensitivity for TUS than CXR in the detection of pneumothorax. While the widely reported sensitivities (49%–100%) for TUS detection of pneumothoraces has not been explained, a more important point is that, in each of these studies, the sensitivity of TUS was significantly higher than CXR. Sonographic specificities were not significantly different from those of CXR, ranging from 94% to 100%. Furthermore, in the studies where it is reported, the likelihood ratios have ranged from 36 to 153.2–4 Since a typical benchmark of a useful test is one that can generate positive likelihood ratios of greater than 10, these test characteristics have persuaded many, including the authors of two systematic reviews, that TUS is a more accurate test than supine anteroposterior CXR for the detection of pneumothorax. Finally, we would also like to take issue with the assumptions underlying the phrase ‘ready availability of chest x-rays’. For many critical care and emergency department patients with sudden unexplained dyspnoea, the delay involved in obtaining a ‘stat’ portable CXR can be lethal. For such patients, bedside TUS may allow for rapid initiation of life-saving interventions.

We are keenly aware that TUS has pitfalls, and that its use requires due caution by properly trained sonologists. However, recognising that guidelines are living documents reflecting best evidence,5 we respectfully submit that the BTS guidelines in question are thus somewhat incomplete. In our view, after further review and consensus development according to the GRADE criteria, data reported from the 21st century, far from being conflicted, provide strong and consistent evidence regarding the superiority of sonography over CXR in the diagnosis of pneumothorax (see online supplement).

The World Interactive Network Focused on Critical Ultrasound (WINFOCUS) International Liaison Committee on Pleural and Lung Ultrasound (ILCPLUS) is constituted by experts in pleural and lung ultrasound and clinical epidemiology experts in the process of evidence assessment, including GRADE and RAND Appropriateness Methodologies for the development of evidence-based clinical recommendations and consensus statements.

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Footnotes

  • Competing interests This letter is being written on behalf of the WINFOCUS International Liaison Committee on Pleural and Lung Ultrasound (ILCPLUS). The goal of this group is to promote the use of point of care ultrasound although none of the members has any specific financial conflicts.

  • Provenance and peer review Not commissioned; not externally peer reviewed.

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