ICU Nosocomial Pneumonia Beth Stuebing, MD, MPH

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

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

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

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

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

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%

CPIS Guide for when to get a specimen

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

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

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

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

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

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

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

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

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

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

Complications Parapneumonic effusion Extrapulmonary infection Drug resistance Prolonged intubation Death!

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

Questions ???