Lung ABC’s

This 84 year old male patient was managed in the MICU for septic shock after presenting to the ED with abdominal pain, decreased appetite, and fatigue. During our routine scanning of patients in the MICU we noted that patient exhibited a A and B lines intermixed throughout the various lung fields. Notably in the right upper lung field prominent B lines were found to intermittently obscure A lines with respirations. Lung sliding was noted throughout. In consideration of this we expanded the fields beyond what we normally would survey in search of a consolidation and were able to locate a shred sign was noted in the R PLAPS fields. The left lung exhibited an A profile in the three fields imaged. These finding were consistent suggestive of consolidation. Given the right upper lobe pathology, we considered that the pattern may have been consistent with aspiration. We did later learn that the night before the patient had been intubated due to episodes concerning for aspiration. Chest X ray confirmed that patient had patchy consolidation that with interval increase from 2 days prior.

This case was of particular interest to me, because with the ultrasound findings we were able to predict the imaging and even some of the clinical history. We were also able to adapt our exam in response to our findings to search out more specific findings.

A quick review of some lung US findings:
• A-profile: anterior lung-sliding with A-lines.
• A’-profile: A-profile with abolished lung-sliding.
• B-profile: anterior lung-sliding with lung-rockets.
• B’-profile: B-profile with abolished lung-sliding.
• C-profile: indicates anterior lung consolidation, regardless of size and number. A thickened, irregular pleural line is an equivalent.
• A/B profile: half A-profile at one lung, a half B-profile at another.
• Shred sign: the irregular border of consolidated and aerated, drawing the fractal line. Evidence of non trans lobar consolidation.

The lung profiles allow one to utile the BLUE protocol algorithm to direct them towards common lung pathology as causes of respiratory distress. Our patient nicely exhibited the A/B (as well as the C) profile which is suggestive of a pneumonia.

Lichtenstein, Daniel A. Lung ultrasound in the critically ill. Ann Intensive Care. 2014; 4: 1. Published online 2014 Jan 9. doi: 10.1186/2110-5820-4-1 PMCID: PMC3895677

-Jeff Nakashioya

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