Ventilator-Associated Pneumonia

1. Ventilator-Associated Pneumonia

2. Introduction • Definition • 48 hours after intubation • mechanically ventilated • No clinical evidence of pneumonia prior to intubation • Time of onset of pneumonia is important • specific pathogens and outcomes • Early-onset VAP (<4 days) • better prognosis, antibioticsensitive • Late-onset VAP (5 days or more) • MDR pathogens • increased patient mortality and morbidity. ATS/IDSA Guidelines: Guidelines for the management of adults with VAP

3. Pathogenic mechanisms

4. Diagnosis and Epidemiology • Difficult • Based on clinical indicators such as new or persistent infiltrates and purulent sputum • Invasive bronchoscopic quantitative methods ( brush and bronchoalveolar lavage) : more precisely • invasive, expensive, and may be less useful in patients with antibiotics • quantitative cultures are not available in all hospitals.

5. ATS/IDSA Guidelines: Guidelines for the management of adults with VAP • Evidence-based guideline • Early, appropriate antibiotics in adequate doses • Avoiding excessive antibiotics • Based on microbiologic cultures, clinical response, shortening the duration to the minimum effective period.

6. Major epidemiologic points • Polymicrobial; especially in ARDS (Level I) • Aerobic • G(-) bacilli (P. aeruginosa, K. P, and Acinetobacter species) • G(+) cocci (S. aureus, much of which is MRSA) • Anaerobes are an uncommon cause (Level II) • Nosocomial virus and fungus are uncommon in immunocompetent patients. (Level I) • MDR pathogens: • severe, chronic underlying disease, late-onset • varies by patient population, and type of ICU (Level II) ATS/IDSA Guidelines: Guidelines for the management of adults with VAP

7. Risk factors for VAP • Duration of mechanical ventilation • Aspiration of gastric contents • COPD • Use of PEEP • Reintubation • Duration of hosptalization • Supine head positioning • (head of bed not elevated) • Fall or winter season • Nasal intubation or sinusitis

8. Modifiable Risk Factors and Recommendation • Intubation and mechanical ventilation • Aspiration, body position and enteral feeding ATS/IDSA Guidelines: Guidelines for the management of adults with VAP

9. Modifiable Risk Factors and Recommendation • Modulation of colonization: oral antiseptics and antibiotics • Stress bleeding prophylaxis, transfusion and glucose control

10. Recommendations for the clinical strategy. • Tracheal aspirate Gram stain can be direct initial therapy • A negative tracheal aspirate has a strong value (94 %) • progressive radiographic infiltrate + 2~3 clinical features represent the most accurate clinical criteria. • Re-evaluation of using antibiotics based on the results of semi-quantitative, by Day 3 or sooner (Level II) ATS/IDSA Guidelines: Guidelines for the management of adults with VAP

11. Recommendations for initial antibiotic therapy • Select an initial empiric therapy based on risk factors for MDR • Local microbiology, cost, availability, and formulary restrictions • For patients who have recently received an antibiotic→ a different antibiotic class ATS/IDSA Guidelines: Guidelines for the management of adults with VAP

12. Initial antibiotic therapy MDR risk factor

13. Initial antibiotic therapy

14. Recommendations for optimal antibiotic therapy • Aerosolized antibiotics: not been proven (Level I) • MDR with poor response : as adjunctive therapy (Level III) • Combination therapy at initial • Though no data compared with monotherapy • aminoglycoside regimen, stopped after 5-7 days (Level III) • If appropriate antibiotic, shorten the duration of therapy as 7 days (not P. aeruginosa !) (Level I).

15. Recommendations for selected MDR pathogens • Combination therapy is recommended. • Resistance ↑on monotherapy • Appropriate and effective (Level II) • Acinetobacter: carbapenems, sulbactam, colistin, polymyxin. • ESBL+ Enterobacteriaceae: monotherapy of carbapenems (Level II) • Adjunctive therapy ( inhaled aminoglycoside or polymyxin) for MDR G(-) (Level III) • Linezolid is an alternative to vancomycin • MRSA, renal insufficiency, nephrotoxic agents (Level III).

16. Ventilator Circuit Change and VAP UpToDate November 16, 2005

17. Ventilator circuit change • Most important routes of bacterial invasion • aspiration of oropharyngeal secretions • inhalation of aerosols containing bacteria • Common colonization of circuits with large numbers of microorganisms. • Circuits were changed daily? 2~3 days? • not a benign procedure, particularly for critically ill patients. • Cost and time !!

18. Summary of Studies

19. Recommendations • Recommend that ventilator circuits can be changed at weekly • Less frequent intervals without increasing the risk of VAP • Required if gross soiling with blood or vomitus occurs • The impact upon VAP is presently unclear for issues • heated versus unheated circuits • artificial noses versus heated humidifiers.

20. Summery

21. Summery • MDR pathogens • A lower respiratory tract culture needs to be collected • Negative cultures: stop antibiotic therapy • An empiric therapy regimen should include agents that are from a different antibiotic class than the patient has recently received.

22. Summery • Combination therapy and short-duration (5 days) • P. aeruginosa: aminoglycoside + ß-lactam • Linezolid is an alternative to vancomycin, for proven MRSA. • Aerosolized antibiotics to MDR pathogens. • Ventilator circuits changed at weekly

23. References • ATS/IDSA Guidelines: Guidelines for the management of adults with HAP, VAP, and HCAP American Thoracic Society, Am J Respir Crit Care Med 2005; 171:388. • Ventilator circuit change and ventilator-associated pneumonia UpToDate November 16, 2005

24. Thanks for attention!