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Paediatric pneumonia? Lung Ultrasound.

If you are a regular reader then you will know that I have been spruiking lung ultrasound for a few years now.  In fact I wrote this post [ Ultrasound for pneumonia – sounds crazy? ]  way back in early 2012.  There continues to be a slow trickle of studies looking at US for pneumonia – and like a lot of US literature – the numbers are small in each paper.

In March 2015 Pediatrics published a systematic review titled:

Lung Ultrasound for the Diagnosis of Pneumonia in Children: A Meta-analysis by Perada et al.  This was a metanalysis of 8 smaller studies (2 in neonates) which showed that lung US performed well as a diagnostic tool compared to CXR.  The papers used a variety of “US users” from expert to novice sonographers.

The diagnostic characteristics have been reasonably variable across these small trials and they give the following as their overall analysis of lung US for pneumonia:

  • Sensitivity 96%,  Specificity  93%,
  • + Likelihood ratio = 15.3      -ve Likelihood ratio = 0.06
  • if you are into “area under the ROC” – it was 0.98 – which is pretty good!

These figures are our best estimate of the utility of LUS for pneumonia in kids.  They are significantly better than the characterisitics of traditional plain film.

So, are we there yet?  Is there enough evidence to change practice?

I think that there is.

Lung US is at least “non-inferior” to CXR.  US carries no risk of radiation and is a fast and technically easy scan to do in small people.  The cost is …  a few dollops of gel and the time to do the scan.

There will certainly be a risk of overdiagnosis given the relatively high sensitivity of US and the potential to misinterpret findings.  This is going to require education and training around image interpretation.  As with all point-of-care US – one needs to interpret the images in the clinical context and be prepared to do another test if the data doesn’t make sense.

So I would love to hear your thoughts –

  • is there enough here to change practice?
  • what barriers are there in your practice to change imaging preferences?

Want to learn how to do this scan??

check this video tutorial from Sonokids / Kasia Hampton

My tips on technique:

  • lots of data to get by looking at the bases: look for effusion, unilateral B lines,
  • The middle lobes collapse to leave a wedge based laterally – this is high in the axilla in little kids – so you need to get up into the armpits to see this common site of consolidation.
  • Anterior zones are easy to scan – zip down each midclavicular line
  • Always correlate with you clinical findings. e.g.. if you think it is bronchiolitis clinically, and you see bilateral posterobasal, small sub-pleural consolidations – then it is bronchiolitis…. NOT bilateral pneumonia
  • Keep using CXR and correlate until you are comfortable, but remember that 20 -30 % of sonographic pneumonias will be invisible on CXR [it is a more sensitive test]. So don’t be surprised if you get imaging that disagree

Let me know how you go.

Casey

 

Comments

  1. I think we are there. I recall you showing this at RMA2012 -- and since then its been an issue of practice, practice, practice and ensuring access to POCUS in clinic

    Bottomline -- need good quality low cost POCUS available in clinics…need training early in career for new cohort and you need to practice to get good results.

    Its such a useful adjunct -- hard to see why would not use it

    • Domagoj Damjanovic says:

      “Need training early in career….” oh yes! Trying to implement pocus education into regular med teaching. Students love it, hungry for more. See no reason why wait till exam time. But hard piece of work to convince leaders and get sufficient resources-like anywhere. .. US machines all around here, only need to train the users. Some experience or advice as to organize education anew, anyone?

  2. Geoff Menzies says:

    Magic stuff. Thanks. Maybe I’m not doing it right, but I am clicking on links and seeing lots of sensitivity and specificity, but not actually what am I supposed to be doing with the probe and the patient. A little help here. Ta.

  3. Jordan Schooler says:

    I’d love to start learning this, although I notice most of the lung ultrasound studies use a curvilinear probe, which I don’t have in the ICU. It seems to me the ultrasound literature is often overly optimistic about the ease of learning new exams. Still, the chest x-ray is a pretty limited test and very subjective, and it would be great to have something better.

  4. JOHN CROSS says:

    Thanks Casey for this update and I agree updated sonography will be great. I did not get at what time of the clinical process we will see sonographic changes e.g. unwell with PUO, no respiratory distress and nil else to account for PUO…..Clinically from my past experience it seems the diagnosis and Rx occurs well before CX-ray confirms it.
    Cheers

  5. Karl Cassidy says:

    http://www.theguardian.com/australia-news/2015/nov/24/ms-dhu-death-inquest-doctors-would-have-made-a-lot-more-effort-if-she-was-white

    Does this throw a spanner in the works?… or just one of those things that could happen anyway?

Trackbacks

  1. […] we change the standard diagnostic strategy for pneumonia in kids from CXR to US? Casey Parker discusses a recent article and argues for just that change. […]

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