ADC/DFTB Journal Club #3 – January – POCUS vs Pneumonia?

Diagnosing pneumonia can be tricky. Each year, 1.2 million children under five years of age die from pneumonia. In developed countries, the incidence is 0.05 per person-year. Pneumonia can imply both bacterial or viral, and there is a distinct challenge in differentiating between these given similar clinical and investigative pictures, or even the presence of pneumonia at all.

What about some POCUS? Can we utilise this investigative modality to spot a child with pneumonia?  The paper from Archives of Disease of Childhood featured in our third #DFTB_JC sought to answer this question.

Lissaman C, Kanjanauptom P, Ong C, et al Prospective observational study of point-of-care ultrasound for diagnosing pneumonia Archives of Disease in Childhood 2019;104:12-18.

What’s it about?

The general sentiment from the Twitter discussion was that making a diagnosis of pneumonia is challenging. More specifically, there’s no reliable way of differentiating between viral and bacterial pneumonia, nor any particularly strong evidence for whom should or should not receive antibiotic therapy.

Most of those actively contributing (including Sarah McNab, Edd B, Damian Roland & Ding online identified the use of clinical skills; with an emphasis on history (of fever, cough) and examination features (pallor, focal chest findings), with the use of chest radiograph (or roentgenogram if you’re feeling formal), to augment or refute this diagnosis.

Blake (@cobra6blake) suggested a 2017 JAMA review article by Shah et al. as a good summary.

The authors methodology made sense with respect to answering the stated question regarding the diagnostic accuracy of LUS vs CXR for diagnosing pneumonia, using this approach:

Although there are well established pros and cons for each modality there was a distinct lack of congruity about which modality was the more accurate, including the rates of agreement between both operators. Jessica Wong (@jessicawswong) also identified Dominguez et al.’s related 2018 article in the Journal of Paediatrics and Child Health.

Sonia Twigg and Damian Roland identified the intricacies of anatomic pathology, citing the difference between the clinical entity of pneumonia and the pathologic entity of hepatisation (grey vs red); I recommend Robbins’ pathology for a refresher.

Pneumonia and LRTI are/look the same same on the ultrasound. The USS findings they sought were “lung consolidation” (I would use the word hepatisation) and air bronchograms. I think we often use the word pneumonia when we find a large, focal area of hepatisation.

— Sonia Twigg (@LankyTwig) 22 January 2019

For me, this is the crux of the matter. Comparing radiological methods is great, but the real question to be answered is “Is LUS better than CXR at selecting patients that will benefit from treatment?”. Which is an extremely tough question to answer, and not managed by this paper

— Edd B (@edd_broad) 22 January 2019

Both Sonia & Edd B have identified the key challenge with the paper (and frankly acknowledged the next step, nicely summarised by Lassi et al in this Cochrane Review (emphasis mine).

For me personally, this paper has sought to highlight an emerging utilisation of POCUS; whilst it contributes to – rather than definitively answering – the evidence and understanding around both paediatric pneumonia and the availability and utility of USS & CXR.

In my view the value of USS would be by clinicians to augment clinical exam where there is not immediate access to CXR (eg. primary care). It’s not practical to put a load of radiographers in ED or wherever these children are being seen to scan lots of febrile children. #DFTB_JC

— David King (@davidking83) 22 January 2019

So, a short summary of what we’ve discussed;

– CXR is the “Gold standard” Ix, but the clinical diagnosis of pneumonia remains the most accepted, with occasional augmentation via CXR

– LUS vs CXR are roughly comparable, both with flaws regarding isolated accuracy & predictability

– This study hasn’t been designed to inform whom should receive treatment, but it’s what we’d all like to know

– POCUS is an emerging skill set for emergency +/- paediatric providers to consider

Thanks again to everyone who participated in our #DFTB_JC and we hope you will join us again later this month for our next paper, thanks to #ADC_BMJ.

“Drug preparation and administration errors during simulated paediatric resuscitations”

Things will be kicking off on Twitter at UTC 2000hrs, 21/02/2019. with this paper…

Murugan S, Parris P, Wells M. Drug preparation and administration errors during simulated paediatric resuscitations. Archives of disease in childhood. 2018 Nov 9:archdischild-2018.

If you want to level up your POCUS skills then why not sign up to one of our point of care ultrasound workshops. They are going to take place on the Sunday before DFTB19. Check out the website for more details.