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Ventilator-Associated Pneumonia (VAP). . Overview. Morbidity, mortality and cost associated with VAPWho gets VAP? Risk factors that increase likelihood of developing VAPEtiology: The bugs Treatment: The drugsHow VAP develops (Pathogenesis)Measures to prevent VAP. Definition-
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1. Donald Dumford’s Senior Talk
3. Overview Morbidity, mortality and cost associated with VAP
Who gets VAP? Risk factors that increase likelihood of developing VAP
Etiology: The bugs
Treatment: The drugs
How VAP develops (Pathogenesis)
Measures to prevent VAP
4. Definition- “Know thy enemy” 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
5. CDC definition of pneumonia
6. 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
7. VAP at UH# cases/1000 ventilator days
8. 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
9. 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
11. 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)
12. Who gets VAP? (Risk factors) Increased risk with . . .
Witnessed aspiration (Risk ratio=3.25)
Administration of paralyzing agent (risk ratio=1.57)
Decreased risk with . . .
Exposure to antibiotics (Risk ratio=0.37)
Risk ratio=0.94 per antibiotic prescribed
At day 5=0.3
At day 10=0.43
At day 15=0.62
At day 20=0.89
13. VAP Morbidity, Mortality and Cost
14. Length of stay and cost Remember that Medicare is no longer reimbursing for nosocomial infections
VAP increased length of stay in the ICU by 5-7 days (mean of 6.1 days)1,2
Increase in cost
Increase of $10,000-$40,000 per patient 1,2
15. Increased mortality Attributable mortality rates ranging from 5.8-13.5%1
In systematic review by Safdar et al, patients with VAP found to be twice as likely to die as those without VAP (Pooled odds ratio 2.03)2
1 CDC.gov. Guidelines for preventing health-care-associated pneumonia, 2003.
2 Safdar N et al. Clincial and economic consequences of ventilator-associated pneumonia: a systematic review
16. Etiology AKA- the Bugs
17. Etiology Early vs. Late VAP1
Early onset= Pneumonia develops within 96 hours (4 days) of patient’s admission to the ICU or intubation for mechanical ventilation
Late onset= Pneumonia develops after 96 hours (4 days) of patient’s admission to the ICU or intubation for mechanical ventilation
Very early onset= within 48 hours after intubation2
1 CDC.gov. Guidelines for preventing health-care-associated pneumonia, 2003.
2 Park DR. The microbiology of ventilator-associated pneumonia.
18. The Bugs Figure 1 from Park
19. The Bugs
20. Etiology- select risk factors for pathogens
21. Risks for MDR
22. Treatment
23. Treatment
24. Treatment- Early onset VAP with no risk factors, any disease severity
25. Treatment- Late onset or risk factors for MDR or all disease severity
26. Pathogenesis
27. Pathogenesis
28. Pathogenesis
29. Pathogenesis 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
30. Oropharyngeal colonization 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)
31. Colonization of oropharynx
32. GI 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
33. Supine patients Studies using radioactive labeling of gastric contents showed that radioactive counts were higher in larynx of supine patients
One of the studies showed the same organisms in stomach, pharynx and endobronchial samples1
Drakulovic et al. studied rate of VAP and found it to be higher in supine compared to semi-recumbent patients2
34. Tracheal colonization Cendrero et al:
25 patients of 110 studied developed VAP
In these 25 patients, 22 had their trachea colonized 3.63 days prior to diagnosis of VAP
17 of the 22 had oropharyngeal colonization prior to trachea
Only 7 had prior colonization of the stomach
35. Pathogenesis- Through the tube Condensate in tubing
Development of ETT biofilm
36. Condensate Condensate in ventilator tubing becomes rapidly contaminated with bacteria from patient’s oropharynx
Craven et al showed that 33% of inspiratory circuits were colonized within 2 hours and 80% within 24 hours
37. ET tube biofilm Exopolysaccharide outer layer with quiescent bacteria within
Difficult for bacteria to penetrate outer layer and bacteria within resistant to bactericidal effects of bacteria
Adair et al study
“Microorganisms of high pathogenic potential were isolated from all ETs collected from patients with VAP compared with 30% of ETs from the control group.”
38. ET tube biofilm Furthermore . . .
Study group of VAP patients- 70% found to have tracheal isolates identical to biofilm isolates
Control group without VAP- no matching isolates
39. Difficult to kill biofilm organismsComparison of MBC of antibiotics for tracheal isolates vs. biofilm isolates
40. Prevention
41. Preventive strategies Around the tube
Through the tube
Less tube
42. Around the tube Oral decontamination and selective decontamination of the digestive tract
Aspiraton of subglottic secretions including continuous aspiration of subglottic secretions
Semi-recumbent positioning
Sucralfate for stress ulcer prophylaxis
43. Oral decontamination- 2 meta-analyses Chlebicki and Safdar investigating the use of chlorhexidine in intubated patients
From Chlebicki and Safdar- relative risk reduction of 30%
Effect most substantial for cardiac surgery patients
Concluded by research team that chlorhexidine likely delays rather than prevents VAP
44. Oral decontamination Chan et al. investigated antibiotics and antiseptics
Antibiotics were not found to be beneficial
Antiseptics were found to be beneficial in 6 out of 7 studies
Chlorhexidine studied in 6, five of which showed benefit
Note that mortality, ICU stay and duration of mechanical ventilation were not statistically significant
46. SDD- selective decontamination of the digestive tract Multiple studies showing effectiveness
Big concern is antibiotic resistance
Most recently- NEJM January 2009
Study of 13 intensive care units in Netherlands showed statistically significant reduction of mortality of 3.5% in patients receiving SDD
Same study showed that patients receiving SOD (selective oropharyngeal decontamination) had decrease of 2.9%
47. Subglottic secretion drainage Meta-analysis of Dezfulian et al showed risk ratio of 0.51 for development of VAP
Also found that those receiving secretion developed VAP 3.1 days later than control
Study groups also averaged 1.8 less days of VAP
49. Drainage of subglottic secretions
50. Continuous aspiration of subglottic secretions (CASS)
51. Semi-recumbent positioning Reduces episodes of aspiration
As mentioned previously, study by Drakulovic et al showed lower rates of VAP in patients in semi-recumbent position
Recommended by CDC and ATS/IDSA guidelines
52. Stress Ulcer Prophylaxis Sucralfate vs. PPI
In recent studies there was no VAP benefit in those receiving sucralfate and these patients also had higher incidence of GI bleed
53. Via the tube Ventilator circuit changes
Condensate
Silver-lined ET tubes
54. Ventilator circuit management Craven and colleagues showed that ventilator circuit change every 24 hours compared to 48 hours increased VAP incidence
Several later studies showed that circuit changes could be used safely for greater than 48 hours
55. Ventilator circuit management 1999 study by Kollef et al.
Randomized clinical trial looking at circuit change every 7 days vs. no routine circuit change
Study group incidence=24.5%
Control group incidence=28.8%
Cost of ventilator circuit changes
$7410 control group
$330 for study group
56. Condensate management Heat-moisture exchanger
Theoretical advantage=prevents bacterial colonization of tubing
Studies= Mixed results
Disadvantage=increases dead space and resistance to breathing
Heated wire to elevate temp of inspired air
Advantage=Decreases condensate formation
Disadvantage=Blockage of ET tube by dried secretions
57. Condensate management Nurse and provider education regarding management of tubes with patient position change or manipulation of bed to ensure that condensate in tubing does not flow towards patient
58. Silver-lined ET tube Broad-spectrum antimicrobial activity in vitro
Reduces bacterial adhesion to devices in vitro
Blocks biofilm formation on the device in animal models
Dog model- decreased severity of lung colonization
59. Silver-lined ET tube NASCENT study- prospective, randomized, single-blind, controlled study
Relative risk reduction of VAP=35.9%
Delayed incidence of VAP
No significant reduction in mortality
60. Through the tube and around the tube Inhaled prophylactic antibiotics
61. Inhaled prophylactic antibiotics Current controversial and more studies needed
Major concern is development of antibiotic resistance
No mortality benefit
62. Less tube Nurse implemented sedation protocol
63. Sedation protocol implementation 2007 study by Quenot et al.
Control phase without nurse-implemented sedation protocol followed by study phase with nurse-implemented sedation protocol
Study phase had significantly shorter duration of MV (4.2 days) and lower incidence of VAP (6% vs. 15%)
64. UH bundle Head of bed elevated above 30 degrees
Oral care q4H
Suctioning q4H
Stress ulcer prophylaxis
65. References American Thoracic Society, Infectious Diseases Society of America. Guidelines for the management of adults with hospital-acquired, ventilator-associated, and healthcare-associated pneumonia. Am J Respir Crit Care Med 2005; 171: 388-416.
Horan TC, Andrus M, Dudreck MA. CDC/NHSN surveillance definition of health-care associated infection and criteria for specific types of infection in the acute care setting. Am J Infect Control 2008; 36:309-32.
Cook DJ, Walter SD, Cook RJ, Griffith LE, Guyatt GH, Leasa D, Jaeschke RZ, Crun-Buisson. Incidence of and risk factors for ventilator-associated pneumonia in critically ill patients. Ann Intern Med 1998; 129: 433-440.
Safdar N, Dezfulian C, Collard HR, Saint S. Clinical and economic consequences of ventilator-associated pneumonia: a systematic review. Crit Care Med 2005; 33: 2184-93.
Park DR. The microbiology of ventilator-associated pneumonia. Resp care 2005; 50: 742-65.
66. References Rello J, Ollendorf DA, Oster G, Vera-Llonch M, Bellm L, Redman R, Kollef MH. Epidemiology and outcomes of ventilator-associated pneumonia in large US database. Chest 2002; 122: 2115-2121.
2003 Guidelines for preventing health-care associated pneumonia. Recommendations of CDC and the healthcare infection control practices advisory committee. CDC.gov.
Kollef MH, Skubas NJ, Sundt TM. A randomized clinical trial of continous aspiration of subglottic secretions in cardiac surgery patients. Chest 1999; 116:1339-46.
Safdar N, Crnich CJ, Maki DG. The pathogenesis of ventilator-associated pneumonia: its relevance to developing effective strategies for prevention. Resp Care 2005; 50: 729-41.
Scannapieco FA, Steward EM, Mylotte JM. Colonization of dental plaque by respiratory pathogens in medical intensive care patients. Crit Care Med 1992; 20: 740-5.
Kollef MH, Afessa B, Anzuesto A, et al. Silver-coated endotracheal tubes and incidence of ventilator-associated pneumonia: the NASCENT randomized trial. JAMA 2008; 300: 805-813.
67. References 12) Drakulovic MB, Torres A, Bauer TT, Nicolas JM, Nogue S, Ferrer M. Supine body position as risk factor for nosocomial pneumonia in mechanically ventilated patients: a randomised trial. The Lancet 1999; 354: 1851-58.
13) Hess DR. Patient positioning and ventilator-associated pneumonia. Resp Care 2005; 50: 892-99.
14) Cendrero JAC, Sole-Violan J, Benitez AB, Catalan JN, Fernandez JA, Santana PS, de Castro FR. Role of different routes of tracheal colonization in the development of pneumonia in patients receiving mechanical ventilation. Chest 1999; 116: 462-70.
15) Collard HR, Saint S, Matthay MA. Prevention of ventilator-associated pneumonia: an evidence-based systematic review. Ann Int Med 2003; 138: 495-501
16) Dezfulian C, Shojanic K, Collard HR, Kim HM, Matthay MA, Saint S. Subglottic secretion drainage for preventing ventilator-associated pneumonia. Am J Med 2005; 118:11-18.
17) Adair CG et al. Implications of endotracheal tube biofilm for ventilator-associated pneumonia. Intensive Care Med 1999; 25: 1072-76.
68. Thank you Any questions?