ventilator associated pneumonias

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Ventilator associated pneumonias

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  • 1.Dr.T.V.Rao MD
    Ventilator-Associated Pneumonias (VAP)

2. Pneumonia can bea life threatening condition
Nosocomial pneumonia (NP), hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP), is an important cause of morbidity and mortality in hospitalized patients. One of the factors contributing to a high mortality rate of HAP and VAP could be antibiotic resistance among the causative agents.
3. Ventilator Associated Pneumonia (VAP)
Ventilator Associated Pneumonia (VAP) is pneumonia occurring in a patient within 48 hours or more after intubation with an endotracheal tube or tracheostomy tube and which was not present before. It is also the most common and fatal infection of ICU
4. Ventilator Associated Pneumonia (VAP)
VAP is the 2nd most common nosocomial infection = 15% of all hospital acquired infections
Incidence = 9% to 70% of patients on ventilators
Increased ICU stay by several days
Increased avg. hospital stay 1 to 3 weeks
Mortality= 13% to 55%
Centers for Disease Control and Prevention, 2003.
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5. Challenge and Controversy
The diagnosis and management of VAP remains one of the most controversial and challenging topics in management of critically ill patients.
6. Centres for Disease and Control
The diagnosis of pneumonia in mechanically ventilated patients is difficult, and still there is no "gold-standard" diagnostic method. It is usually based on the combination of clinical, radiological, and microbiological criteria defined by Centres for Disease and Control (CDC)
7. 7
Incidence
It is often difficult to define the exact incidence of HAP and VAP, because there may be an overlap with other lower respiratory tract infections, such as tracheobronchitis, especially in mechanically ventilated patients)
The exact incidence of HAP is usually between 5 and 15 cases per 1,000 hospital admissions depending on the case definition and study population; the exact incidence of VAP is 6- to 20-fold greater than in nonventilated patients
8. Mechanical ventilation predisposes to VAP
HAP accounts for up to 25% of all ICU infections
In ICU patients, nearly 90% of episodes of HAP occur during mechanical ventilation
9. Nosocomial infection are Multidrug Resistant
Many patients with HAP, VAP, and HCAP are at increased risk for colonization and infection with MDR pathogens
HAP and VAP are a frequent cause of nosocomial infection that is associated with a higher crude mortality than other hospital-acquired infections
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10. Definition Ventilator Associate Pneumonia
Pneumonia that develops in someone who has been intubated
-Typically in studies, patients are only included if intubated greater than 48 hours
-Early onset= less than 4 days
-Late onset= greater than 4 days
Endotracheal intubation increases risk of developing pneumonia by 6 to 21 fold
Accounts for 90% of infections in mechanically ventilated patients
.
11. Prevalence of VAP
Occurs in 10-20% of those receiving mechanical ventilation for greater than 48 hours
Rate= 14.8 cases per 1000 ventilator days
12. When does VAP occur?
Cook et al showed . . .
40.1% developed before day 5
41.2% developed between days 6 and 10
11.3% developed between days 11-15
2.8% developed between days 16 and 20
4.5% developed after day 21
Cook et al. Incidence of and risk factors for ventilator-associated pneumonia
in critically ill patients.
13. 14. Time frame of intubation and risk
Risk of pneumonia at intubation days
3.3% per day at day 5
2.3% per day at day 10
1.3% per day at day 15
.
15. Who gets VAP?(Risk factors)
Study of 1014 patients receiving mechanical ventilation for 48 hours or more and free of pneumonia at admission to ICU
Increased risk associated with admitting diagnosis of :
Burns (risk ratio=5.09)
Trauma (risk ratio=5.0)
Respiratory disease (risk ratio=2.79)
CNS disease (risk ratio=3.4)
16. 16
17. PAHOGENESIS
The pathogenesis of ventilator-associated pneumonia usually requires that two important processes take place:
Bacterial colonization of the aero digestive tract
The aspiration of contaminated secretions into the lower airway.
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18. 18
19. Etiology
Bacteria cause most cases of HAP, VAP, and HCAP and many infections are polymicrobial; rates are especially high in patients with ARDS
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20. VAP Etiology
Most are bacterial pathogens, with Gram negative bacilli common:
Pseudomonas aeruginosa
Proteus spp
Acinetobacter spp
Staphlococcus aureus
Early VAP associated with non-multi-antibiotic-resistant organisms
Late VAP associated with antibiotic-resistant organism
21. Common and Uncommon isolates in VAP
HAP, VAP, and HCAP are commonly caused by aerobic gram-negative bacilli, such as P. aeruginosa, K. pneumoniae, and Acinetobacter species, or by gram-positive cocci, such as S. aureus, much of which is MRSA; anaerobes are an uncommon cause of VAP
22. Drug resistance a concern in Ventilator Associated Pneumonias
A. baumanni was the most common isolated pathogen many of them were multidrug-resistant (MDR) or pan drug-resistant (PDR). The other common isolated pathogens were K. pneumoniae, P. aeruginosa and methicillin-resistantS. aureus (MRSA).
23. 23
Other Isolates in Ventilator associated Pneumonias
Pseudomonas aeruginosa.
the most common MDR gram-negative bacterial pathogen causing HAP/VAP, has intrinsic resistance to many antimicrobial agents
Klebsiella, Enterobacter, and Serratia species.
Klebsiella species
intrinsically resistant to ampicillin and other aminopenicillins and can acquire resistance to cephalosporins and aztreonam by the production of extended-spectrum lactamases (ESBLs)
However ESBL-producing strains remain susceptible to carbapenems
Enterobacter species
Citrobacter and Serratia species
24. Acinetobacter speciesAcinAcinetobacter species
Acinetobacter species
More than 85% of isolates are susceptible to carbapenems, but resistance is increasing
Stenotrophomonas maltophilia, and Burkholderia cepacia:
resistant to carbapenems
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25. Acinetobacter species a Growing Concern
Acinetobacter species
More than 85% of isolates are susceptible to carbapenems, but resistance is increasing
An alternative for therapy is sulbactam
Stenotrophomonas maltophilia, and Burkholderia cepacia:
Resistant to carbapenems
Susceptible to trimethoprimsulfamethoxazole, ticarcillinclavulanate, or a fluoroquinolone
26. 26
Staphylococcus aureus and Streptococcus pneumoniae
Methicillin-resistant Staphylococcus aureus
vancomycin-intermediate S. aureus
sensitive to linezolid
linezolid resistance has emerged in S. aureus, but is currently rare
Streptococcus pneumoniae and Haemophilus influenzae.
sensitive to vancomycin or linezolid, and most remain sensitive to broadspectrum quinolones
27. L. Pneumophila andenvironment
Rates of L. pneumophila vary considerably between hospitals and disease occurs more commonly with serogroup 1 when the water supply is colonized or there is ongoing construction
27
28. Influenza too can cause VAP
Nosocomial virus and fungal infections are uncommon causes of HAP and VAP in immunocompetent patients. Outbreaks of influenza have occurred sporadically and risk of infection can be substantially reduced with widespread effective infection control, vaccination, and use of anti influenza agents
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29. Fungal pathogens can cause VAP
Fungal pathogens.
Aspergillus species
Candida albicans
30. Pathogenesis Entry of Pathogens
Where do the bacteria come from?
Tracheal colonization- via oropharyngeal colonization or GI colonization
Ventilator system
How do they get into the lung?
Breakdown of normal host defenses
Two main routes
Through the tube
Around the tube- microaspiration around ETT cuff
31. Causative Organisms
Early onset:
Hemophilus influenza
Streptococcus pneumoniae
Staphylococcus aureus (methicillin sensitive)
Escherichia coli
Klebsiella pneumoniae
Late onset:
Pseudomonas aeruginosa
Acinetobacter spp.
Staphylococcus aureus (methicillin resistant)
Most strains responsible for early onset VAP are antibiotic sensitive. Those responsible for late onset VAP are usually multiple antibiotic resistant
Am J Resp Crit Care (1995)
32. Oropharyngeal colonization can be source of VAP
Scannapieco et al showed a transition in the colonization of dental plaques in patients in the ICU
Control=25 subjects presenting to preventive dentistry clinic
Study group=34 noncardiac patients admitted to medical ICU at VA hospital (sampled within 12 hours of admission and every third day)
33. Gastrointestinal colonization
Increased gastric pH leads to bacterial overgrowth
Reflux can then lead to colonization of oropharynx
Use of antacids and H2 blockers associated with GI colonization
Safdar et al. The pathogenesis of ventilator-associated pneumonia:
its relevance to developing effective strategies for prevention
34. Viral Pathogens
Outbreaks of HAP, VAP, and HCAP due to viruses, such as influenza, parainfluenza, adenovirus, measles, and respiratory syncytial virus have been reported and are usually seasonal.
Influenza, pararinfluenza, adenovirus, and respiratory syncytial virus account for 70% of the nosocomial viral cases of HAP,VAP, and HCAP
35. Multidrug resistant organisms are associated with
The prevalence of MDR pathogens varies by patien

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