1. ICU Nosocomial Pneumonia
Beth Stuebing, MD, MPH

2. Outline Epidemiology Diagnosis – clinical findings
Diagnosis – attaining specimen
Treatment
Complications
Prevention

3. Epidemiology
Ventilator associated pneumonia (VAP) is the most common and deadliest hospital acquired infection in the ICU
10-20% of pts vented >48hrs
2x-10x the mortality of pts without VAP
Although some studies argue no difference in mortality
VAP with Pseudomonas ~40% mortality
Treatment of pneumonia accounts for ½ of antibiotic use in the ICU

4. Risk Factors, Pathogenesis
Just being intubated! Each vented day increases VAP rate 1-3%
Aspiration of oral pathogens around cuff
Aspiration of GI contents
Biofilm within ET tube
Equipment and personnel contamination
Hematogenous spread from another source

5. Patient Related Risk Factors
Suppressed immune system from frequent
blood transfusion (>4 units)
antibiotics
inhaled steroids
Sedated, paralyzed patients unable to clear secretions
Chronic disease, ex. Renal failure, DM
Tobacco use
Antacids, H2 blockers

6. The Culprits Early (<5 days, mortality 22%)
Strep pneumoniae, Staph aureus, sensitive GNR
Late (>5 days, mortality 47%)
MRSA
Pseudomonas in 10-20%
Resistant GNR (Acinetobacter, Klebsiella, E coli, Enterobacter)
50% is polymicrobial

7. Diagnosis – Clinical Findings
Difficult, complex, and frequently debated, because:
Overtreatment is BAD
Undertreatment is WORSE
Sensitivity of VAP clinical diagnosis 58-83% with infiltrates on CXR
Post mortem exam of those suspected of having VAP showed true incidence 30-40%

8. CPIS
Guide for when to get a specimen

9. Infiltrates: not always straight forward
Pneumonia accounts for only 1/3 of infiltrates in ICU pts

10. Diagnosis – attaining specimen
Deep tracheal aspirate not appropriate – contaminated with airway colonizing organisms
Blind or bronchoscopy?
Clinical diagnosis without scope: 15-70% false positive rate – inappropriate abx use, cost, false sense of security
Large French study: invasive diagnosis had decreased mortality, organ dysfunction, and antibiotic use
Other studies show no difference
Bronchoscopy is expensive, needs expertise, may delay initiating treatment

11. Diagnosis: attaining specimen
Bronchoalveolar lavage or protected specimen brush?
Qualitative or quantitative culture?
Quantitative cultures are standard of care
Routine “surveillance” cultures are NOT advised, and rarely identify the pathogen of VAP that evolves later
Presence of squamous cells, absence of macrophages indicates upper airway secretions instead of deep specimen

12. Protected Specimen Brush
>10^3 colonies/mL indicative of lower respiratory infection
66% sensitivity, 90% specific

13. Bronchoalveolar Lavage (BAL)
>10^4 colonies/mL positive for infection
Significant WBC with intracellular organisms, no squamous cells
Elevated LDH and IL1B in BAL may correlate with presence of pneumonia
73% sensitive, 82% specific – most accurate

14. Future Directions in Diagnosis
Measuring immunoglobulin-triggering receptor expressed on myeloid cells (sTREM-1)
98% sensitive and 90% specific for pneumonia in one study of 148 patients
Measuring procalcitonin – appears to rise with bacterial pneumonia and worsening sepsis
May also be helpful as prognostic indicator, even when to stop antibiotics

15. Treatment
Empiric broad coverage for patients considered truly infected
New or worse infiltrate plus 2 of 3: purulent sputum, fever, leukocytosis
CPIS >6
Know your ICU antibiogram
Incorrect initial antiobiotics results in increased morbidity, mortality, length of stay, and cost

16. Antibiotic Choice Early -> limited spectrum
Ceftriaxone, unasyn, augmentin, fluoroquinolone
Late, septic, prior hospitalization, h/o MDR
Add MRSA coverage, pseudomonas coverage (double coverage debatable)
48-72 hr reevaluation
De-escalate according to culture
Escalate for worsening, resistance

17. Duration of Antibiotics
6-8 days of appropriate coverage
Extending >8 days of no benefit
Some recommend adding aminoglycoside for first 5-7 days
Double coverage of Pseudomonas is controversial – only shown benefit in 1 study in patients with bacteremia, not pneumonia

18. Lack of Response
Microbiologic response is faster than clinical response
Occult unrecognized source somewhere else (in 50% of pts with VAP)
Line, sinusitis, c diff, uti, empyema
Repeat specimen with bronchoscopy may be useful
No survival benefit shown with lung biopsy
Consider noninfectious causes: sarcoid, vasculitis, hypersensitivity pneumonitis, bronchiolitis obliterans organizing pneumonia (BOOP), granulomatosis

20. Complications Parapneumonic effusion Extrapulmonary infection
Drug resistance
Prolonged intubation
Death!

21. Prevention Limit tubes, esp. nasal, avoid reintubation
Adequately inflate ETT cuff
Avoid over-sedation
Daily spontaneous breathing trials
Elevate head of bed at least 30 degrees
Use noninvasive vent when possible
Oral hygiene with antiseptic
Early tracheostomy
Healthcare staff hand hygiene
Change circuit only when necessary
Enteral feedings instead of parenteral
Bolus vs continuous of debatable benefit

22. Questions ???