ventilator associated pneumonias

74
DR.T.V.RAO MD Ventilator- Associated Pneumonias (VAP)

Upload: tumalapalli-venkateswara-rao

Post on 11-May-2015

6.200 views

Category:

Health & Medicine


1 download

DESCRIPTION

Ventilator associated pneumonias

TRANSCRIPT

Page 1: Ventilator associated pneumonias

DR.T.V.RAO MD

Ventilator-Associated

Pneumonias (VAP)

Page 2: Ventilator associated pneumonias

Pneumonia can be a 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.

Page 3: Ventilator associated pneumonias

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

Page 4: Ventilator associated pneumonias

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.

;

Page 5: Ventilator associated pneumonias

Challenge and Controversy

The diagnosis and management of VAP remains one of the most controversial and challenging topics in management of critically ill patients.”

Page 6: Ventilator associated pneumonias

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)

Page 7: Ventilator associated pneumonias

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

Page 8: Ventilator associated pneumonias

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

Page 9: Ventilator associated pneumonias

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

9

Page 10: Ventilator associated pneumonias

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.

Page 11: Ventilator associated pneumonias

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

Page 12: Ventilator associated pneumonias

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 pneumoniain critically ill patients.

Page 13: Ventilator associated pneumonias
Page 14: Ventilator associated pneumonias

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 .

Page 15: Ventilator associated pneumonias

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)

Page 16: Ventilator associated pneumonias

16

Page 17: Ventilator associated pneumonias

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.

17

Page 18: Ventilator associated pneumonias

18

Page 19: Ventilator associated pneumonias

Etiology Bacteria cause most

cases of HAP, VAP, and HCAP and many infections are polymicrobial; rates are especially high in patients with ARDS

19

Page 20: Ventilator associated pneumonias

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

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

Page 21: Ventilator associated pneumonias

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

Page 22: Ventilator associated pneumonias

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-resistant S. aureus (MRSA).

Page 23: Ventilator associated pneumonias

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

Page 24: Ventilator associated pneumonias

Acinetobacter species

AcinAcinetobacter species Acinetobacter species

More than 85% of isolates are susceptible to carbapenems, but resistance is increasing

Stenotrophomonas maltophilia, and Burkholderia cepacia: resistant to

carbapenems

24

Page 25: Ventilator associated pneumonias

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 trimethoprim–

sulfamethoxazole, ticarcillin–clavulanate, or a fluoroquinolone

Page 26: Ventilator associated pneumonias

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

Page 27: Ventilator associated pneumonias

L. Pneumophila and environment

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

Page 28: Ventilator associated pneumonias

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

28

Page 29: Ventilator associated pneumonias

Fungal pathogens can cause VAP

Fungal pathogens.Aspergillus species

Candida albicans

Page 30: Ventilator associated pneumonias

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

Page 31: Ventilator associated pneumonias

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)

Page 32: Ventilator associated pneumonias

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)

Page 33: Ventilator associated pneumonias

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

Page 34: Ventilator associated pneumonias

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

Page 35: Ventilator associated pneumonias

Multidrug resistant organisms are associated with …

The prevalence of MDR pathogens varies by patient population, hospital, and type of ICU, which underscores the need for local surveillance data

MDR pathogens are more commonly isolated from patients with severe, chronic underlying disease, those with risk factors for HCAP, and patients with late-onset HAP or VAP

35

Page 36: Ventilator associated pneumonias

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 patients

Page 37: Ventilator associated pneumonias

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

Page 38: Ventilator associated pneumonias

Infected biofilms too contribute to increased incidence of VAP

Infected biofilm in the endotracheal tube, with subsequent embolization to distal airways, may be important in the pathogenesis of VAP

Page 39: Ventilator associated pneumonias

ET tubes increases Biofilm formation

Exopolysaccharide outer layer with quiescent bacteria within Difficult for bacteria

to penetrate outer layer and bacteria within resistant to bactericidal effects of bacteria

Page 40: Ventilator associated pneumonias

Difficult to kill biofilm organisms

Comparison of MBC of antibiotics for tracheal isolates vs. biofilm isolatesOrganism Tobramycin Cefotaxime Cefuroxime

P. aeruginosa-Tracheal-ET

256>1024

32>1024

>1024>1024

Enterobacteriaceae-Tracheal-ET

4>1024

128256

32512

S. aureus-Tracheal-ET

18>1024

16128

16>1024

Page 41: Ventilator associated pneumonias

41

Clinical Strategy in Diagnosis of VAP

Clinical Strategy The presence of a new or progressive

radiographic infiltrate At least two of three clinical features fever greater than 38_C, leukocytosis or leukopenia, purulent secretions

Represents the most accurate combination of criteria for starting empiric antibiotic therapy.

Page 42: Ventilator associated pneumonias

Pathogens in VAP (1)

Pathogens that cause VAP differ depending on whether the condition occurs early (less than 96 hours after intubation or admission to ICU) or late (greater than 96 hours after intubation or admission to ICU)

Page 43: Ventilator associated pneumonias

Pathogens in VAP (2)

Early–Onset Pneumonia (< 96 hours of intubation or ICU admission) Community-acquired Pathogens:

Streptococcus pneumoniae

Haemophilus influenzae

Staphylococcus aureus

Antibiotic-sensitive ?

Page 44: Ventilator associated pneumonias

Pathogens in VAP (3) Late-Onset

Pneumonia (> 96 hours of intubation or ICU admission) Hospital-acquired Pathogens:

Pseudomonas aeruginosa Methicillin resistant

Staphylococcus aureus (MRSA)

Acinetobacter Enterobacter

Antibiotic-resistant ???

Page 45: Ventilator associated pneumonias

Diagnosis is imprecise and usually based on a Combination

of

Clinical factors - fever or hypothermia; change in secretions; cough; apnea/ bradycardia; tachypnea

Microbiological factors - positive cultures of blood/sputum/tracheal aspirate/pleural fluids

CXR factors - new or changing infiltrates

Page 46: Ventilator associated pneumonias

Strategies in Diagnosis in VAP are multifaceted

Clinical Strategy

Bacteriologic Strategy

Comparing Diagnostic Strategy

46

Page 47: Ventilator associated pneumonias

Gram stain is highly sensitive

Sputum or tracheal suction gram stain NO ORGANISMS

in non-neutropenic pts.

NO HAP/VAP 94%

Page 48: Ventilator associated pneumonias

Gram staining of secretions are useful in early

decisions The upper respiratory tract of patients is colonized with potential pulmonary pathogens a few hours after intubation. A positive Gram's stain may guide the initial antibiotic therapy. However prior antibiotic and corticosteroid therapy can reduce the sensitivity of this technique

Page 49: Ventilator associated pneumonias

Bacterial culture of tracheal secretion

Qualitative culture - non specific Semi-quantitative

culture - low specificity Quantitative culture

: TS, BAL, PSB - increase

specificity

Page 50: Ventilator associated pneumonias

Specimen collection for Optimal Results

Distal airway samples may be obtained by using bronchoscopic or nonbronchoscopic techniques. With nonbronchoscopic techniques, a catheter is blindly advanced through the endotracheal tube or tracheostomy and wedged in the distal airway. Various sampling methods include blind bronchial suction (BBS), blind BAL, and blind PSB sampling.

Page 51: Ventilator associated pneumonias

Semiquantitative

1+ : rare <10 colonies/plate2+: few 10-102 colonies/plate3+: moderate >102-3 colonies/plate4+: numerous >103-4 colonies/plate5+: numerous >104 colonies/plate

Page 52: Ventilator associated pneumonias

Tracheal aspirates are valuable specimens

A reliable tracheal aspirate Gram stain can be used to direct initial empiric antimicrobial therapy and may increase the diagnostic value of the CPIS

A negative tracheal aspirate (absence of bacteria or in-flammatory cells) in a patient without a recent (within 72 hours) change in antibiotics has a strong negative predictive value (94%) for VAP and should lead to a search for alternative sources of fever

52

Page 53: Ventilator associated pneumonias

Bacteriologic Strategy

Quantitative cultures can be performed on endotracheal aspirates or samples collected either bronchoscopically or nonbronchoscopically, and each technique has its own diagnostic threshold and methodologic limitations. The choice of method depends on local expertise, experience, availability, and cost

doctortvrao
Page 54: Ventilator associated pneumonias

Bacterial culture of tracheal secretion

Qualitative culture - non specific Semi-quantitative culture - low specificity Quantitative culture : TS, BAL, PSB - increase specificity

Page 55: Ventilator associated pneumonias

Collection of bronchial Secretions

Distal airway samples may be obtained by using bronchoscopic or nonbronchoscopic techniques. With nonbronchoscopic techniques, a catheter is blindly advanced through the endotracheal tube or tracheostomy and wedged in the distal airway. Various sampling methods include blind bronchial suction (BBS), blind BAL, and blind PSB sampling.

Page 56: Ventilator associated pneumonias

Qualitative and quantitative 

Qualitative endotracheal aspirates are easy to obtain but have a high false-positive rate in ICU patients because of airway colonization. When quantitative endotracheal-aspirate cultures are used, a cutoff value of 106 is the most accurate, with a sensitivity of 38-82% and a specificity of 72-85%

Page 57: Ventilator associated pneumonias

False negative – False Positive Results

Investigators reported that the clinical diagnosis of VAP is associated 30–35% false-negative and 20–25% false-positive results . And also, ICU patients do not always have systemic signs of infection due to their underlying disease (chronic renal failure)

Page 58: Ventilator associated pneumonias

Other Supporting Bacterial Cultures

Bacteraemia and positive pleural effusion cultures are generally considered to be able to identify the organisms causing the pneumonia, if no other source of infection is found. Therefore, most experts recommend that investigation of suspected VAP should include taking two sets of blood samples for culture and tapping pleural  > 10 mm, even though spread to the blood or pleural space occurs in < 10% of VAP

Page 59: Ventilator associated pneumonias

Multiresistant pathogens in Ventilator associated

pneumonias The incidence of multiresistant pathogens is also closely linked to local factors and varies widely from one institution to another. Consequently, each ICU must continuously collect meticulous

epidemiologic data

Page 60: Ventilator associated pneumonias

Uncommon microbes are often missed

Legionella species , anaerobes fungi viruses, and even Pneumocystis carinii should be mentioned as potential causative agents but are not considered to be common in the context of pneumonia acquired during MV. However, several of these causative agents may be more common and potentially underreported because of difficulties involved with the diagnostic

Page 61: Ventilator associated pneumonias

61

Comparing Diagnostic Strategy

A patients with suspected VAP should have a lower respiratory tract sample sent for culture, and extrapulmonary infection should be excluded, as part of the evaluation before administration of antibiotic therapy

If there is a high pretest probability of pneumonia, or in the 10% of patients with evidence of sepsis, prompt therapy is required, regardless of whether bacteria are found on microscopic examination of lower respiratory tract samples

Page 62: Ventilator associated pneumonias

Microbiologists / Physicians should consider other Diagnostic

results Pugin et al. proposed to combine the seven variables (temperature, leukocytes, tracheal aspirate volume and purulence of tracheal secretions, chest X-ray, oxygenation-PaO2/FiO2- and semi quantitative culture of tracheal aspirate) for the diagnosis of VAP, defined as clinical pulmonary infection score (CPIS)

Page 63: Ventilator associated pneumonias

Mortality

Appropriate Mortality

Inappropriate Mortality

Early Mortality

Evidence-based early and appropriate therapy in VAP

Page 64: Ventilator associated pneumonias

Best option in choosing Antibiotics

Considerations in making selection Setting (community, NH, hospital) Suspected organism (GNRs, GPCs) Host factors (immunosuppression) Local susceptibility patterns

Initial empiric and broad; subsequent narrowing Concept is to not miss the organism with

initial coverage and then de-escalate when able

Page 65: Ventilator associated pneumonias

Continuous Removal of Subglottic Secretions

Use an ET tube with continuous suction through a dorsal lumen above the cuff to prevent drainage accumulation

Use an ET tube with continuous suction through a dorsal lumen above the cuff to prevent drainage accumulation

Page 66: Ventilator associated pneumonias

HOB ElevationHOB Elevation

HOB at 30-45o

Keep the HOB elevated to at least 30 degrees unless medically contraindicated

HOB at 30-45o

Keep the HOB elevated to at least 30 degrees unless medically contraindicated

Page 67: Ventilator associated pneumonias

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

secretionsCDC.gov. Guidelines for preventing health-care-associated pneumonia, 2003.

Page 68: Ventilator associated pneumonias

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

Page 69: Ventilator associated pneumonias

HandwashingHandwashing

What role does handwashing play in nosocomial pneumonias? The greatest role

Page 70: Ventilator associated pneumonias

VAP Prevention Wash hands before

and after suctioning, touching ventilator equipment, and/or coming into contact with respiratory secretions.

Page 71: Ventilator associated pneumonias

Epidemiological data differs from situations

The incidence of multiresistant pathogens is also closely linked to local factors and varies widely from one institution to another. Consequently, each ICU must continuously collect meticulous

epidemiologic data

Page 72: Ventilator associated pneumonias

Treating patient with VAP is complex

Successful treatment of patients with VAP remains a difficult and complex undertaking. Despite broad clinical experience with this disease, no consensus has been reached concerning issues as basic as the optimal antimicrobial regimen or its duration. In fact, to date, evaluation of various antimicrobial strategies for the treatment of bacterial VAP has been difficult for several reasons.

Page 73: Ventilator associated pneumonias

Summary Clinical evidence suggests that

early use of appropriate empiric antibiotic therapy improves patient outcomes in terms of: reduced mortality reduced morbidity reduced duration of hospital stay

Page 74: Ventilator associated pneumonias

Created by Dr.T.V.Rao MD for ‘e’ learning for Medical Professionals

[email protected]