Lung POCUS and the zone wars

Probe positioning is very well defined for echocardiograpy, FAST and vascular scanning.  However with the thorax there is a lot of real estate, and a lot of lung.  Is there  an agreed plan and language for scanning the lungs?

First a surface anatomy refresher:

09fig_lunglobes
from http://imbus.anwresidency.com/txtbook/03_lung.html

For lung ultrasound assessment for assessment of interstial oedema there seems to be two  main methods, following Volpicelli (Italy)or Lichenstein (France).  Great slides by Lichenstein here.

First I present the 4 lung zones for each hemithorax described by Volpicelli from 2006:

zones_volpicelli
from https://www.youtube.com/watch?v=VzgX9ihnmec

With two zones anteriorly and two under inferior to the axilla.  Different articles seem to variously place the horizontal line at the 3rd or 5th intercostal space.

And the three zones of Lichenstein and the BLUE (Bedside Lung Ultrasound In Emergency) protocol (really six as they divide the three zones into upper and lower, without setting out anatomical borders for upper/lower) from 2008.

lungpocuszoneslichenstein
https://com-anest.sites.medinfo.ufl.edu/files/2015/11/The-Blue-Protocol.pdf

In 2008 there were also two of the Italian workers Copetti & Cattarossi who described POCUS zones for paediatric lung infections were “The probe was placed perpendicular, oblique and parallel to the ribs in the anterior, lateral and posterior (lower and upper) thorax.”, creating six zones on each hemithorax, they don’t provide any guiding images.

Then there are various EM/ICU/CC/Anaesthesia protocols eFAST, RUSH, CCUS,FATE, F-LUS:

m_chest_148_4_912_fig01
CCUS – Critical Care Ultrasound, similar to Volpicelli, adds a 5th zone for dependent pleural fluid (PLAPS -Postero-Lateral Alveolar Pleural Syndrome- see also BLUE protocol) http://journal.publications.chestnet.org/article.aspx?articleid=2297756
efast
eFAST – extended Focused Assessment with Sonography in Trauma – adds two anterior high thoracic and two low lateral thoracic probe positions to the FAST scan
RUSH - Rapid Ultrasound for Shock and Hypotension, two anterior thoracic windows http://sinaiem.us/tutorials/rush/
RUSH – Rapid Ultrasound for Shock and Hypotension, two anterior thoracic windows
http://sinaiem.us/tutorials/rush/
lung portion of FATE (Focus Assessed Transthoracic Echo)
lung portion of FATE (Focus Assessed Transthoracic Echo)
m_chest_144_6_1868_fig01
F-LUS – expansion of FATE( Focused Lung Ultrasound/Focus Assessed Transthoracic Echocardiography) which the authors state is a modification of Lichenstein and Volpicelli http://journal.publications.chestnet.org/article.aspx?articleid=1728827

If you want to really wig out there is a 28 zone protocol to use:

http://handsonecho.com/sites/53072f21c97d797504000002/content_entry530f3ce3c97d79b7c2000279/5470daaac97d7945d40d6b5f/files/How_I_do_it.pdf
http://handsonecho.com/sites/53072f21c97d797504000002/content_entry530f3ce3c97d79b7c2000279/5470daaac97d7945d40d6b5f/files/How_I_do_it.pdf

 

I really just like this pragmatic approach:

wheretoputtheprobe
http://handsonecho.com/sites/53072f21c97d797504000002/content_entry530f3ce3c97d79b7c2000279/5470d878c97d7904e30d4f41/files/Semiotics_A.pdf

What will I be using in general practice? As per my positioning post, clothing access and patient positioning and room ergonomics play a large part of the scanning process for me.  The questions I want to address pneumothorax yes/no, B-lines/interstial oedema yes/no, consolidation yes/no and effusion yes/no would be well answered by any of these however the CCUS five zones (1R, 2R, 3R, 4R, 5R) modification of Volpicelli’s zones seems clear and allow me to have a re-producible note for myself in the patient record and onscreen comments for review scans. For on-referred patients (usually going to the ED for LRTI) I will still use word descriptors because we do not yet have a lingua franca for lung ultrasound zones.

I have not talked about probe selection or probe orientation (mostly perpendicular to ribs to achieve the Bat Wing sign, the FATE low pleural views are parallel to ribs to view lung/diaphragm/liver or spleen) or lung scoring systems.

Another learning point from my reading around these zones was something I have not been doing – scan low on the back to get kidney and then work up when patient is sitting. You will ensure you are low, below diaphragm and as you scan up in area 5R you give yourself the best chance of spotting the curtain sign of the diaphragm and then a dependent effusion.

 

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Author: gppocus

Urban general practioner in Melbourne, Australia

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