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Should point-of-care ultrasonography replace stethoscopes in acute respiratory failure?

BMJ 2019; 366 doi: (Published 30 August 2019) Cite this as: BMJ 2019;366:l5225
  1. Nicholas Smallwood, consultant in acute internal medicine1,
  2. Ashley Miller, consultant in intensive care medicine2,
  3. Andrew Walden, consultant in acute internal and intensive care medicine3,
  4. Mark Hew, consultant in respiratory medicine4 5,
  5. Tunn Ren Tay, consultant in respiratory and critical care medicine6,
  6. Najib M Rahman, professor of respiratory medicine7 8
  1. 1East Surrey Hospital, Redhill, UK
  2. 2Royal Shrewsbury Hospital, Shrewsbury, UK
  3. 3Royal Berkshire Hospital, Reading, UK
  4. 4Respiratory Medicine, Alfred Hospital, Melbourne, Victoria, Australia
  5. 5Public Health and Preventive Medicine, Monash University, Melbourne, Victoria, Australia
  6. 6Department of Respiratory and Critical Care Medicine, Changi General Hospital, Singapore
  7. 7Oxford Centre for Respiratory Medicine, Churchill Hospital, Oxford, UK
  8. 8Oxford NIHR Biomedical Research Centre, Oxford, UK
  1. Correspondence to: N Smallwood nicholas.smallwood{at}, M Hew m.hew{at}

Ultrasonography would be a better diagnostic test than auscultation or chest radiography, say Nicholas Smallwood and colleagues. But Mark Hew and colleagues argue the costs are hard to justify without evidence that it would improve patient outcomes

Yes—Nicholas Smallwood, Ashley Miller, and Andrew Walden

“The most dangerous phrase in the language is, ‘We’ve always done it this way,’” said the US scientist Grace Hopper. And yet, when it comes to diagnosing the cause of acute respiratory failure, the current standard is to use the stethoscope and chest radiography—two technologies with a combined age of over 300 years.

The techniques continue to be used despite their limited diagnostic accuracy mainly because, until recently, there was no available alternative and abandoning old practices is difficult in a traditional profession such as medicine.

Current methods not sensitive or specific

Consider community acquired pneumonia, for example: neither auscultation nor chest radiography are sensitive or specific diagnostic tools. Crackles on auscultation have a sensitivity of 19-67% and a specificity of 36-96%, carrying a positive likelihood ratio of 2.3 and a negative likelihood ratio of 0.8.1 This limits their use in ruling pneumonia in or out because their presence or absence only marginally alters the provisional diagnosis. Inter-observer reliability is poor, with only 72% agreement and a kappa value of 0.41.2

Chest radiography fares only a little better. Even when reported by radiologists, the presence of infiltrates carries only 59% agreement, with an overall kappa value of 0.53 (moderate agreement).3 When chest radiography is compared with computed tomography to assess for the presence of infiltrates, sensitivity is only 43.5%.4

Similar data show the poor diagnostic yield for traditional techniques in the diagnosis of left ventricular dysfunction and other causes of …

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