Adult Guidance
Hospital-Acquired Pneumonia

Hospital-Acquired Pneumonia

Definition

Hospital-acquired pneumonia (HAP): Acute illness affecting the lungs caused by pathogens in the hospital setting and presenting 48 hours or more after admission

Ventilator-associated pneumonia (VAP): Acute illness affecting the lungs caused by pathogens in the hospital setting and presenting 48 hours or more after admission while the patient is on a ventilator

Important

The cut-off of 48 hours is chosen for convenience and surveillance purposes

Diagnosis

Non-ventilated patients: New or worsening cough +/- sputum production, difficult and rapid breathing, reduced oxygen saturation, crepitations on lung auscultation, or chest pain/discomfort with no alternative explanation; fever ≥38.0°C usually present (may be absent, especially in the elderly)

Ventilated patients: Increased respiratory secretions, reduced oxygen saturation and a new lung infiltrate on a chest-radiograph

Note: the clinical presentation is non-specific and other diseases (e.g. pulmonary embolism) can mimic HAP. HAP/VAP may progress to sepsis

All cases:

  • Blood cultures (ideally before starting antibiotics)
  • Microscopy and culture of respiratory samples (ideally before starting antibiotics)
  • Urinary antigens for Legionella pneumophila and Streptococcus pneumoniae

Selected cases (depending on epidemiology and risk factors):

  • Nasopharyngeal swab for influenza viruses and SARS-CoV-2

Important: a positive respiratory culture may indicate colonization rather than acute infection

Determine disease severity: Blood pH and gases, white blood cell count

Differentiate bacterial and viral (taking into account pre-test probability): C-reactive protein and/or procalcitonin

Note: tests depend on availability and clinical severity (e.g. blood gases will only be done in severe cases)

  • If sepsis is suspected consider additional laboratory tests (see sepsis guidance below)

Chest radiograph needed because other conditions have similar clinical features and antibiotics may be avoided if bacterial pneumonia is not suggested

Important:

  • Chest radiographs can be difficult to interpret and correlate with the clinical presentation; many other conditions mimic infectious infiltrates (especially in the elderly) 
  • The radiographic pattern cannot be used to accurately predict the microbial cause

Microbiology

Prevention

Key principles:

  • Vaccination against pathogens that can commonly cause pneumonia
  • Good hand hygiene
  • Maintain mobility
  • Maintain good oral and dental care
  • Maintain nutrition in hospital
  • Elevate the head of the bed to reduce the chances of aspirating respiratory secretions into the lungs
  • Avoid intubation or reduce duration as much as possible

Bundles of care specific to the ICU also usually include:

  • Minimizing sedation
  • Regularly assessing if the endotracheal tube may be removed; extubate patients as soon as it is safe to do so
  • Selective oral decontamination (SOD) and/or selective decontamination of the digestive tract (SDD) to reduce the bacterial burden of the upper (with SOD) and lower (with SDD) digestive tract through the administration of non-absorbable antibiotics
  • SOD/SDD can help reduce the incidence of VAP, yet there is concern about the risk of selecting resistant bacteria

Treatment

  • Important:
    • Consider stopping treatment if HAP is ruled out or an alternative diagnosis can be made
    • If not severely ill, consider targeted treatment based on microbiology results
  • Empiric antibiotic treatment should be guided by:
    • The severity of symptoms (scoring systems exist but are not addressed here), considering local prevalence of resistant pathogens and individual risk factors for resistant pathogens
  • In patients with VAP specifically consider:
    • Need for empiric double anti-pseudomonal coverage (risk of infection caused by isolates resistant to an antibiotic used for monotherapy)
  • Important:
    • Simplify empiric treatment to a more narrow-spectrum antibiotic based on culture results or rapid clinical improvement if culture results unavailable
    • Step down to oral treatment is based on improvement of symptoms, signs of infection and the ability to take oral antibiotics

Additional Information