Consolidation in the dependent segments for the position at the time — posterior upper-lobe and superior lower-lobe segments when supine, basal segments when upright — often with centrilobular tree-in-bud and airway debris.
Orient first
- Risk: reduced consciousness, dysphagia, stroke, alcohol, oesophageal disease.
- Chemical pneumonitis (Mendelson) appears within hours; bacterial pneumonia follows.
- The right lung is more often involved (straighter main bronchus).
Acquire the study
- Chest radiograph; CT chest for complications, cavitation or recurrent aspiration.
The manoeuvre
- Dependent segments for the position: right lower lobe basal segments (upright) or posterior upper and superior lower lobe segments (supine).
- Bilateral basal opacities in the bedridden patient; compare with the prior study.
- Cavitation or abscess and effusion.
What confirms it
- Dependent consolidation in a patient with an aspiration risk or witnessed event.
What licenses you to exclude it
- Clear dependent segments make aspiration pneumonia unlikely.
The classic misread
- Expecting basal disease in a patient who aspirated lying down.
- Missing the oesophageal cause.