Transcript Nosocomial Pneumonia

Nosocomial Pneumonia
Epidemiology
 Common hospital-acquired infection
 Occurs at a rate of approximately 5-10 cases per 1000 hospital
admissions
 Incidence increases by 6-20 fold in patients being ventilated
mechanically.
 One study suggested that the risk for developing VAP increases 1%
per day
 Another study suggested, highest risk occur in the first 5 days after
intubation
Nosocomial Pneumonia
Nosocomial Pneumonia
Epidemiology
 Nosocomial pneumonia is the leading cause of death
due to hospital acquired infections
 Associated with substantial morbidity
 Has an associated crude mortality of 30-50%
 Hospital stay increases by 7-9 days per patient
 Estimated cost > 1 billion dollars/year
Nosocomial Pneumonia
 Hence, the importance of focusing on:
 Accurate diagnosis
 Appropriate treatment
 Preventive measures
Nosocomial Pneumonia
 Pathogenesis
 Risk factors
 Etiologic agents
 Differential diagnosis
 Treatment
 Prevention
Pathogenesis
Nosocomial Pneumonia
 Microaspiration may occur in up to 45% of healthy
volunteers during sleep
 Oropharynx of hospitalized patients is colonized with
GNR in 35-75% of patients depending on the severity
and type of underlying illness
 Multiple factors are associated with higher risk of
colonization with pathogenic bacteria and higher risk of
aspiration
Nosocomial Pneumonia
 Pathogenesis
 Invasion of the lower respiratory tract by:
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Aspiration of oropharyngeal/GI organisms
Inhalation of aerosols containing bacteria
Hematogenous spread
Colonization
Aspiration
MRSA*
HAP
Risk Factors
Nosocomial Pneumonia
 Risk Factors
 Host Factors
 Extremes of age, severe acute or chronic illnesses,
immunosupression, coma, alcoholism, malnutrition, COPD, DM
 Factors that enhance colonization of the oropharynx
and stomach by pathogenic microorganisms

admission to an ICU, administration of antibiotics, chronic lung
disease, endotracheal intubation, etc.
Nosocomial Pneumonia
 Risk Factors
 Conditions favoring aspiration or reflux
 Supine position, depressed consciousness, endotracheal
intubation, insertion of nasogastric tube
 Mechanical ventilation
 Impaired mucociliary function, injury of mucosa favoring
bacterial binding, pooling of secretions in the subglottic area,
potential exposure to contaminated respiratory equipment and
contact with contaminated or colonized hands of HCWs
 Factors that impede adequate pulmonary toilet
 Surgical procedures that involve the head and neck, being
immobilized as a result of trauma or illness, sedation etc.
Etiologic Agents
Nosocomial Pneumonia
 Etiologic Agents
 S.aureus
 Enterobacteriaceae
 P.aeruginosa
 Acinetobacter sp.
 Polymicrobial
 Anaerobic bacteria
 Legionella sp.
 Aspergillus sp.
 Viral
Diagnosis
Nosocomial Pneumonia
 Diagnosis
 Not necessarily easy to accurately diagnose HAP
 Criteria frequently include:
 Clinical
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Radiographic
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new or progressive infiltrates on CXR,
Laboratorial
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fever ; cough with purulent sputum,
leukocytosis or leukopenia
Microbiologic
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Suggestive gram stain and positive cultures of sputum, tracheal
aspirate, BAL, bronchial brushing, pleural fluid or blood
Quantitative cultures
Nosocomial Pneumonia
 Problems
 All above criteria fairly sensitive, but very non- specific,
particularly in mechanically ventilated patients
 Other criteria/problems include
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Positive cultures of blood and pleural fluid plus clinical findings
(specific but poor sensitivity)
Rapid cavitation of pulmonary infiltrate absent Tb or cancer
(rare)
Histopathologic examination of lung tissue (invasive)
Nosocomial pneumonia
 Bronchoscopically Directed Techniques for diagnosis of
VAP and Quantitative cultures
 Bronchoscopy with BAL/bronchial brushings (10,000 to 100,000
CFU/ml and less than 1% of squamous cells)
 Protected specimen brush method (>10³ CFU/ml)
 Protected BAL with a balloon tipped catheter (>5% of neutrophils
or macrophages with intracellular organisms on a Wright-Giemsa
stain)
Nosocomial pneumonia
 Multiple studies looked into the accuracy of quantitative culture and microscopic
examination of LRT secretions as compared to histopathologic examination and tissue
cultures (either lung biopsy or immediate post mortem obtained samples)
 Several trials conclude that use of FOB techniques and quantitative cultures are more
accurate
 At least 4 studies concluded that bronchoscopically directed techniques were not more
accurate for diagnosis of VAP than clinical and X-ray criteria, combined with cultures of
tracheal aspirate
 Therefore no gold standard criteria exist
Nosocomial Pneumonia
 Differential diagnosis
 ARDS
 Pulmonary edema
 Pulmonary embolism
 Atelectasis
 Alveolar hemorrhage
 Lung contusion
Treatment
Nosocomial Pneumonia
 Antimicrobial Treatment
 Broad spectrum penicillins
 3rd and 4th generation cephalosporins
 Carbapenems
 Quinolones
 Aminoglycosides
 Vancomycin
 Linezolid
Inadequate
Antibiotic
Therapy
Antibiotic
Resistance
Nosocomial Pneumonia
 Duration of antimicrobial treatment
 Optimal duration of treatment has not been established
 Most experts recommend 14-21 days of treatment
 Recent data support shorter treatment regimens (8 days)
Prevention
Nosocomial Pneumonia
 Preventive Measures
 Incentive spirometry
 Promote early ambulation
 Avoid CNS depressants
 Decrease duration of immunosupression
 Infection control measures
 Educate and train personnel
Nosocomial Pneumonia
 Preventive Measures
 Avoid prolonged nasal intubation
 Suction secretions
 Semi-recumbent position( 30-45°head elevation)
 Do not change ventilator circuits routinely more often
than every 48 hours
 Drain and discard tubing condensate
 Use sterile water for respiratory humidifying devices
 Subglottic secretions drainage
Craven, et al. Chest. 1995;108:s1-s16.
Nosocomial Pneumonia
 Preventive Measures
 Remove NGT when no longer needed
 Avoid gastric overdistention
 Stress ulcer prophylaxis:

sulcrafate; antacids; H2 receptor antagonists
 Acidification of enteral feedings
 Prophylactic antibiotics
 Inhaled antibiotics
 Selective digestive decontamination
 Chlorexidine oral rinses
 Vaccines ( Influenza; Strep.pneumoniae)