Perform a bedside point-of-care lung ultrasound — OSCE

Candidate brief

You have this station to set up the ultrasound machine, perform a bedside point-of-care lung ultrasound on this febrile, tachypnoeic 8-month-old, interpret the findings, and state the management. Treat the scan as a focused, binary-question examination to be performed in parallel with respiratory support, never in series with it. [1] [3]

Key teaching and management objectives

Begin by stating the clinical question in one sentence: is there a subpleural consolidation of community-acquired pneumonia, or is the pattern one of viral bronchiolitis? A scan without a stated question produces an image without an interpretation. [1]

Next, choose the probe and set the image. A high-frequency linear probe is selected because the pleura and the near lung are superficial in this small infant, and higher frequency buys resolution. Set depth so the pleural line fills the screen, adjust gain so fluid is black and tissue is mid-grey, place the focus at the pleural line, and confirm the probe marker orientation. Apply warm gel generously to exclude any air layer. [1]

Run the eight-zone bilateral scan: divide each hemithorax by the anterior and posterior axillary lines and a horizontal line at the nipple into anterior-upper, anterior-lower, lateral, and posterior zones, and scan both sides in the same order. At each zone read the pleural line between the rib shadows and interpret the artefact repertoire — A-lines for dry air, B-lines for a wet lung, lung sliding that rules out a pneumothorax at that point, the lung point for a partial pneumothorax, and the quad and sinusoid signs for an effusion. [2] [3]

Interpret the pattern with the BLUE protocol in mind. The sign that confirms a community-acquired pneumonia is a subpleural, tissue-like, hypoechoic consolidation that resembles liver and is threaded with dynamic air bronchograms moving with respiration, often with adjacent B-lines; a 2024 meta-analysis found lung ultrasound as accurate as or more accurate than the chest radiograph for paediatric community-acquired pneumonia, with no ionising radiation. A bilateral, diffuse B-line pattern without consolidation would point toward viral bronchiolitis or pulmonary oedema read in context. [3] [4]

Integrate the answer and state the next step out loud. A confirmed consolidation prompts antibiotics and admission; a bronchiolitis pattern prompts supportive care. Document the finding, save representative stills and clips, and escalate to a chest radiograph only if the scan is equivocal or the child is not responding as expected. [1] [4]

Close with the pitfalls. Guard against over-reliance on a single scan by ensuring good gel contact and a perpendicular probe (an oblique probe or a poor gel layer generates spurious B-lines), by scanning the contralateral side as an internal control, and by treating a normal scan with humility in the child who is not responding, because a small central pneumonia or an early effusion may be missed. State that POCUS is adjunctive and never delays oxygen and respiratory support. [2] [3]

Marking domains

• Clinical question and set-up (3 marks). States one binary question; chooses a high-frequency linear probe with a clear rationale; sets depth, gain, focus, and probe orientation; uses warm gel to exclude air.
• Protocol and artefact interpretation (4 marks). Runs the eight-zone bilateral scan; identifies the pleural line between rib shadows; correctly reads A-lines, B-lines, lung sliding, and the consolidation with dynamic air bronchograms; interprets the pattern.
• Integration and management (2 marks). Names the consolidation sign for pneumonia and the radiation-free advantage over the chest radiograph; states the correct next step and when to escalate to formal imaging.
• Pitfalls and safety (3 marks). Names the artefact-as-pathology pitfalls and the contralateral-control manoeuvre; states that POCUS is adjunctive and never delays respiratory support; documents and saves images. [1] [4]