Synopsis
Diagnose hospital-acquired or ventilator-associated pneumonia without mistaking colonisation or non-infective infiltrates for infection, obtain useful microbiology promptly, and start proportionate empirical therapy guided by severity and local resistance data.
- Hospital-acquired pneumonia develops 48 hours or more after admission and was not incubating at entry; ventilator-associated pneumonia usually begins more than 48 hours after endotracheal intubation.
- Require a compatible new clinical syndrome—fever or hypothermia, purulent secretions, inflammatory response, worsening gas exchange—and new or progressive radiographic infiltrate; no single sign proves VAP.
- Distinguish pneumonia from atelectasis, pulmonary oedema, aspiration pneumonitis, pulmonary embolism, acute respiratory distress syndrome, alveolar haemorrhage and ventilator-associated tracheobronchitis.
- Send a good-quality lower-respiratory sample before antibiotics when this causes no harmful delay; interpret growth against prior colonisation, airway device, Gram stain and the clinical trajectory.
- Choose empirical antibiotics using illness severity, time in hospital, recent antibiotics, previous resistant isolates, local ICU ecology, renal function, allergy and the possibility of MRSA.
- NICE recommends starting treatment as soon as possible after diagnosis and within 4 hours; sepsis pathways may require still faster administration.
- Review IV therapy and microbiology at about 48 hours, narrow or stop when the diagnosis is unsupported, and review after 5 total days with stopping considered when clinically stable.
- Prevention centres on minimising unnecessary ventilation and sedation, safe airway care, head-up positioning when appropriate, oral care, hand hygiene and antimicrobial stewardship.
Key red flags
New or progressive infiltrate with worsening oxygenation, increased or purulent secretions and systemic inflammatory features after more than 48 hours of invasive ventilation; rising ventilator support is a severity marker.
Shock, organ dysfunction, rapidly increasing FiO2, late onset, recent broad-spectrum antibiotics, known resistant colonisation, bronchiectasis or prolonged ICU exposure justify urgent broad initial cover and specialist review.
Investigation priorities
Identify a new infiltrate and complications while comparing with prior films.
Management branches
Suspected HAP or VAP with new physiological deterioration.
- Perform ABCDE assessment, prescribe target-based oxygen, check the airway and ventilator circuit, obtain chest imaging and involve critical care early for shock or escalating support.
- Review admission timing, aspiration, recent procedures, fluid balance, antibiotics, prior cultures and resistance risks; search for non-pulmonary sepsis and common radiographic mimics.
- Collect lower-respiratory and blood cultures when indicated without harmful delay, then start a locally approved empirical regimen within the NICE timeframe.