Synopsis
Decide whether a new hospital-onset pulmonary deterioration is bacterial pneumonia, use prior colonisation and local resistance data to choose proportionate treatment, and de-escalate safely once respiratory microbiology and the clinical trajectory are known.
- Hospital-acquired pneumonia is considered when symptoms begin at least 48 hours after admission and infection was not incubating on arrival; disease appearing on days 3 to 5 without resistance risk may still follow the community-acquired regimen.
- Diagnosis requires a new lower-respiratory syndrome and new or progressive imaging change after considering oedema, atelectasis, aspiration pneumonitis, pulmonary embolism, ARDS and alveolar haemorrhage.
- Endotracheal tubes become colonised quickly. A resistant organism in sputum or tracheal aspirate changes probability but does not prove that it is invading lung tissue.
- Before empirical treatment, review recent antibiotics, earlier cultures, known MRSA or multidrug-resistant Gram-negative carriage, structural lung disease, immune suppression and the current ward or ICU antibiogram.
- NICE advises antibiotics as soon as possible after HAP is suspected and within 4 hours; suspected sepsis may require the shorter sepsis-specific timeframe.
- Use oral treatment first for non-severe low-resistance-risk disease when absorption is reliable; severe illness, VAP or resistance risk requires a locally selected intravenous regimen and microbiology input.
- At 48 hours revisit whether pneumonia remains credible, then stop, narrow, change route or define an end date. Review after 5 total days and consider stopping when clinically stable.
- Prevention is cumulative: remove avoidable devices, reduce unnecessary ventilation and sedation, maintain safe oral and airway care, mobilise, prevent aspiration and avoid antimicrobial exposure without an indication.