Overview
Hospital-Acquired Pneumonia and Ventilator-Associated Pneumonia
Topic Overview
Summary
Hospital-acquired pneumonia (HAP) is pneumonia developing 48 hours or more after hospital admission. Ventilator-associated pneumonia (VAP) occurs 48 hours or more after endotracheal intubation. Both are associated with high morbidity and mortality. Causative organisms include gram-negatives (Pseudomonas, Klebsiella, E. coli), Staphylococcus aureus (including MRSA), and Enterobacteriaceae. Treatment requires broad-spectrum antibiotics tailored to local resistance patterns. Prevention bundles reduce VAP incidence.
Key Facts
- HAP: Pneumonia over 48 hours after hospital admission
- VAP: Pneumonia over 48 hours after intubation
- Organisms: Gram-negatives (Pseudomonas), S. aureus (MRSA), Enterobacteriaceae
- Diagnosis: Clinical + radiological (CXR/CT) + microbiological
- Treatment: Broad-spectrum antibiotics (de-escalate based on cultures)
- Prevention: VAP care bundles
Clinical Pearls
Early-onset (under 5 days) usually sensitive organisms; Late-onset (over 5 days) more resistant organisms
Always consider Pseudomonas and MRSA if risk factors present
De-escalate antibiotics once culture results available
Why This Matters Clinically
HAP and VAP are common, costly, and deadly. Early appropriate antibiotics improve survival. Preventive measures reduce incidence significantly.
Visual Summary
Visual assets to be added:
- HAP/VAP diagnostic criteria
- Organism patterns by timing
- VAP bundle components
- Empirical antibiotic algorithm
Epidemiology
Incidence
- HAP: 5-10 per 1,000 hospital admissions
- VAP: 5-15% of ventilated patients
- Most common ICU-acquired infection
Mortality
- HAP: 10-30%
- VAP: 20-50%
Risk Factors
| Factor | Notes |
|---|---|
| Mechanical ventilation | Major risk for VAP |
| Prolonged hospital stay | Colonisation with resistant organisms |
| Previous antibiotics | Selects resistant flora |
| Immunocompromise | |
| Chronic lung disease | |
| Aspiration risk | Reduced consciousness, dysphagia |
| Acid suppression | PPIs increase gastric colonisation |
Pathophysiology
Mechanism
- Colonisation of oropharynx with hospital organisms
- Aspiration of secretions into lower airways
- Failure of host defences → pneumonia
Routes of Infection
- Microaspiration (most common)
- Inhalation (ventilator circuits)
- Haematogenous spread (rare)
- Direct inoculation (suctioning)
Organisms
Early-Onset (Under 5 Days):
- Streptococcus pneumoniae
- Haemophilus influenzae
- MSSA
- Community-type organisms
Late-Onset (Over 5 Days):
- Pseudomonas aeruginosa
- MRSA
- Acinetobacter
- Extended-spectrum beta-lactamase (ESBL) producers
- Stenotrophomonas
Clinical Presentation
Symptoms
Signs
VAP Features
Red Flags
| Finding | Significance |
|---|---|
| Sepsis | Urgent — source control and antibiotics |
| Rapid deterioration | May need escalation of care |
| Multi-drug resistant organism | Adjust antibiotics |
Fever (or hypothermia)
Common presentation.
Increased oxygen requirements
Common presentation.
Increased/purulent secretions
Common presentation.
Cough
Common presentation.
Dyspnoea
Common presentation.
Clinical Examination
Vital Signs
- Fever (over 38°C) or hypothermia
- Tachycardia
- Tachypnoea
- Hypoxia
Respiratory
- Crackles
- Bronchial breathing
- Reduced breath sounds (consolidation)
Secretions
- Increased volume
- Purulent (green/yellow)
Investigations
Blood Tests
| Test | Purpose |
|---|---|
| FBC | WCC (raised or low) |
| CRP, procalcitonin | Inflammation; procalcitonin may guide duration |
| U&E, creatinine | Renal function (antibiotic dosing) |
| Blood cultures | Identify bacteraemia |
| Lactate | Sepsis |
Microbiology
| Sample | Notes |
|---|---|
| Sputum culture | If expectorating |
| Tracheal aspirate | VAP |
| Bronchoalveolar lavage (BAL) | Gold standard for VAP |
| Blood cultures | Essential |
Imaging
| Modality | Findings |
|---|---|
| CXR | New or worsening infiltrates |
| CT chest | If CXR inconclusive or complications suspected |
Clinical Pulmonary Infection Score (CPIS)
- Combines clinical, radiological, and microbiological criteria
- Score over 6 suggests pneumonia
Classification & Staging
By Timing
| Type | Definition |
|---|---|
| HAP | Pneumonia over 48h after admission |
| VAP | Pneumonia over 48h after intubation |
| Early-onset | Under 5 days (usually sensitive organisms) |
| Late-onset | Over 5 days (more resistant organisms) |
By Severity
- Non-severe
- Severe (sepsis, respiratory failure)
Management
Empirical Antibiotics — Start Early
Low Risk of MDR (Early-Onset, No Risk Factors):
| Regimen | Notes |
|---|---|
| Co-amoxiclav | First-line |
| Ceftriaxone | Alternative |
| Respiratory fluoroquinolone | Levofloxacin |
High Risk of MDR (Late-Onset, Prior Antibiotics, ICU):
| Regimen | Notes |
|---|---|
| Piperacillin-tazobactam | Anti-pseudomonal |
| Meropenem | If ESBL risk |
| + Vancomycin or linezolid | If MRSA risk |
| + Aminoglycoside | Consider if Pseudomonas |
De-escalation
- Review cultures at 48-72 hours
- Narrow spectrum based on sensitivities
- Stop if no evidence of pneumonia
Duration
- Generally 7 days (longer if Pseudomonas, slow response)
- Procalcitonin-guided stopping may reduce duration
Supportive Care
- Oxygen/ventilatory support
- Fluid resuscitation if septic
- Nutritional support
VAP Prevention Bundle
| Intervention | Notes |
|---|---|
| Head of bed elevation | 30-45 degrees |
| Daily sedation hold | Assess for extubation |
| DVT prophylaxis | |
| Oral care | Chlorhexidine mouthcare |
| Avoid unnecessary PPI | Reduces gastric colonisation |
Complications
Pulmonary
- Lung abscess
- Empyema
- ARDS
- Respiratory failure
Systemic
- Sepsis
- Multi-organ failure
- Death
Other
- Prolonged mechanical ventilation
- Increased length of stay
Prognosis & Outcomes
Mortality
- HAP: 10-30%
- VAP: 20-50%
- Higher with MDR organisms
Factors Affecting Outcome
- Appropriate initial antibiotics
- Time to treatment
- Organism resistance
- Patient comorbidities
Evidence & Guidelines
Key Guidelines
- NICE NG139: Pneumonia (Hospital-Acquired)
- IDSA/ATS Guidelines on HAP and VAP
Key Evidence
- Early appropriate antibiotics improve survival
- VAP bundles reduce incidence by up to 50%
Patient & Family Information
What is HAP/VAP?
Hospital-acquired pneumonia is a lung infection that develops while you are in hospital. Ventilator-associated pneumonia occurs when someone on a breathing machine develops pneumonia.
Why Does it Happen?
- Being unwell makes it harder to fight off infections
- Tubes and equipment can allow germs into the lungs
Treatment
- Antibiotics through a drip
- Oxygen or breathing support
- Close monitoring
Prevention
- Hospital staff take precautions to prevent infections
- Good oral hygiene helps
Resources
References
Primary Guidelines
- NICE. Pneumonia (Hospital-Acquired): Antimicrobial Prescribing (NG139). 2019. nice.org.uk
- Kalil AC, et al. Management of Adults With Hospital-acquired and Ventilator-associated Pneumonia: 2016 Clinical Practice Guidelines (IDSA/ATS). Clin Infect Dis. 2016;63(5):e61-e111. PMID: 27418577
Key Reviews
- Torres A, et al. International ERS/ESICM/ESCMID/ALAT guidelines for the management of hospital-acquired pneumonia and ventilator-associated pneumonia. Eur Respir J. 2017;50(3):1700582. PMID: 28890434