This document discusses ventilator-associated pneumonia (VAP) and its diagnosis and treatment. It defines VAP and other types of nosocomial pneumonia like ventilator-associated tracheobronchitis (VAT) and healthcare-associated pneumonia (HCAP). Risk factors, pathogenesis, epidemiology, etiologic agents, diagnosis using tools like clinical pulmonary infection score (CPIS), and treatment approaches are summarized. Emphasis is placed on preventing VAP through bundles and identifying multidrug-resistant pathogens given high attributable mortality rates.
1. DR IMRAN GAFOOR
DR DEBASHISH DHAR
DEPTT OF CRITICAL CARE &
EMERGENCY MEDICINE
SIR GANGARAM HOSPITAL
2. VAP : ventilator associated pneumonia is a
nosocomial pneumonia which develops in ICU
patients who have been tracheally
intubated/MV ≥ 2 days.
VAT : ventilator associated tracheobronchitis,↑
in volume & purulence of resp secretions,fever
leucocytosis but no radiological infiltrates.
3. HCAP : health care associated pneumonia.
RISK FACTORS
- hospitalzn. For ≥ 2 days within preceding 90
days,
- residencein nursing home or extended care
facility,
- home infusion therapy (antibiotics)
- chronic dialysis within 30 days,
- home wound care
- family member with MDR pathogens
4. OTHER CLASSIFICATION :
PRIMARY ENDOGENOUS PNEUMONIA –
causative micro-organisms are isolated in surv-
eillance cultures on admission.
SECONDARY ENDOGENOUS PNEUMONIA-
causative micro-organisms later on colonize
oropharynx/GIT & reach lower resp tract
EXOGENOUS PNEUMONIA –
pt is not a previous carrier but colonised by
ventilator tubes ,bronchoscopes,humidifiers etc.
5. EARLY vs LATE ONSET VAP :
EARLY ONSET (<4 days) –
antibiotic sensitive,better prognosis
LATE ONSET (5 days or more) –
MDR pathogens,increased mortality
There were no significant differences in the prevalence of
potential MDR pathogens associated with early-onset or late-
onset VAP, even in subjects with prior antibiotics. Empiric
therapy for early-onset VAP should also include agents likely to
be effective for potential MDR pathogens.
Respir Care. 2013 Jul;58(7):1220-5.
6. TROVILLET et al found that two variables
were significant for predicting infection with
MDR VAP :
- mechanical ventilation ≥ 7 days
- prior antibiotic use esp broad spectrum
EPIDEMIOLOGY :
second most common nosocomial infection
but leading cause of attributable mortality
(33-50%)
7. Incidence of HAP in india is 53.9%.
Incidence of VAP in india is 8.95/1000
ventilator days.
Mortality rate(attributable) is 37% - 47.3%
Park Es et al Am j inf control(2000)
9. • It is estimated that 9-27% of patient undergoing
MV for > 2 days are affected by VAP.
. Cook et al demonstrated that,risk of VAP is 3%
on first 5 days of MV,2% from 5-10 days,& 1%
for remaining days.
MORTALITY : Several cross matching studies
have estimated that one third to half of all VAP
related deaths are result of
pseudomonas/acinetobacter pneumonia with
bacteremia.
- mortality is inversely related to adequacy of
initial empirical thereapy.
10. - Correct & prompt treatment of pneumonia
results in better patient survival.
- Inappropriate therapy is strongly associated
with worse survival.
PATHOGENESIS :
* Pulmonary aspiration of colonised
(whether endo/exogenous) oropharyngeal
secretions across tracheal tube cuff is the
main pathogenic mechanism for development
of VAP.
12. * Tracheal intubation is the “conditio sine qua
non‖ for development of pneumonia because it
facilitates aspiration of pathogens & hinders
intrinsic respiratory defenses.
* Normally ETT has ‗HVLP‘ cuff,the potential
diameter of which is two to three times larger
than tracheal diameter,so,when tracheal cuff
is inflated within trachea,folds invaraibly form
along cuff surface,causing consistent
micro/macro aspiration of oropharyngeal
secretions.
14. * ETT is commonly made of PVC & bacteria
easily adhere to its internal surface forming a
complex structure called BIOFILM (sessile
bacteria embedded within a self produced
exopolysaccharide matrix)
* ETT biofilm is difficult to eradicate &
constitutes a persistent source of colonization.
SOURCES OF COLONIZATION :
- hands of ICU staff
- colonised bronchoscopes
- water supply
16. - respiratory equipments
- humidifiers
- ventilator temp sensors
- nebulizers
- contaminated environment.
- In critically ill patients endogenous oral flora
shifts early to aerobic gram – pathogens (pse-
udomonas,MRSA),pulmonary aspiration of
which leads to pneumonia.
17. * Azarpazhooh et al showed that improved oral
hygiene & frequent professional oral health
care reduces progression or occurrence of
respiratory infection among patients in ICU.
* Orotracheal as compared to nasotracheal intu-
bation is associated with a decreased incidence
of sinusitis & thus VAP.
IMPAIREMENT OF RESPIRATORY
DEFENSES DURING CRITICAL ILLNESS
& TRACHEAL INTUBATION :
- no protection from adduction of true/false
vocal cords.
18. - no protection from epiglottis
- cough not possible
- tracheally intubated patients have very low
muco ciliary velocity (0.8-1.4mm/min)–
higher risk for pulmonary complication.
- Temporary immunoparalysis during early
course of ICU stay (low levels of HLA-DR
expression on monocytes),may predispose to
colonization.
19. ETIOLOGIC AGENTS :
* VAP is commonly caused by aerobic gram –
bacilli(peudomonos,E.coli,klebsiella,acine-
tobacter),while S.AUREUS is predominant
gram + organism.
• EPIC-II study confirmed that pseudomonos &
staph aureus are most common isolated patho-
gens in ICU.
UNDERLYING DISEASES :
- patients with COPD have higher risk for H.infl,
moraxella,pseudomonos,pneumococcus,
aspergillus
20. In a study of nosocomial pneumonia in 51 ICU
patients in india,the most commonly isolated
organisms were
P.auroginosa(20%), Acinetobacter spp
(38%),klebsiella(23%),
MRSA(5%).The data also clearly demonstrate that the incidence
and prevalence of multidrug-resistant pathogens are
rising in Asian countries. A. baumannii–calcoaceticus
complex is emerging as a major pathogen in most of
the ICUs in these countries. MRSA, although present,
is not as big a problem as in the Western world;
doi:10.1016/j.ajic.2007.05.011
21. - Candida & aspergillus are m/c isolated fungi in
immunocompromised.
- Recent reviews show that candida in
respiratory samples demonstrate only
colonosation rather than pneumonia.
- Viruses causing VAP : HSV-I,CMV
- PREVENTIVE STRATEGIES FOR
NOSOCOMIAL PNEUMONIA :
1) Implementation ,as VAP bundle,of noso-
comial pneumonia preventive strategies
that have proven efficacy in reducing mo-
rbidity & mortality.
22. 2) Implementation of education programmes
(respiratory care physicians & nurses being
primary recepients),& frequent performance
feedbacks & compliance assesment.
3) Strict alcohol based hand hygiene.
4) Avoidance of tracheal intubation & use of NIV
when indicated(acute exacebn. of COPD,
acute hypoxemic resp failure,immunocomp.
with pulmonary infiltrates)
-Recent reports emphasize role of NIV in
preventing re-intubation in recently extubated
pts at risk for relapse & respiratory failure.
23. 5) Daily sedation vacation & implementation of
weaning protocols.
6) No ventilatory circuit tube changes unless soiled
or damaged.
7) Use of tracheal tubes with cuff made of novel
materials(polyurethane; & LVLP cuffs made of
silicone &latex) & shape(conical)
8)Application of low level PEEP(5-8cm
H2O)during tracheal intubation.
9) Use of silver coated ETT –
NASCENT trial concluded that silver coated
ETT has ↓ incidence of VAP,↓ mortality in pts
with VAP,is cost effective & has greatest
impact during first 10 days.
24. 10) Aspiration of subglottic secretions(every 4-
6hrs)
11) Internal cuff pressure maintained within 25-30
cm H2O & carefully controlled during
transport of patients outside ICU.
12) Earlier tracheostomised pts (mean~7 days)
had shorter length of M/V & ICU stay,a ↓trend
towards pneumonia but no survival benefit as
compared to late tracheostomy(mean~14 days)
13) Routine saline instillation before tracheal
suctioning not recommended
25. 14) Intubated pts should be kept in semi-
recumbent position(30-45°),rather than supine
to prevent aspiration;especially when enterally
fed.
15) Continuous lateral rotation of bed helps to
reduce extravascular lung water,improveV/Q
& enhance mobilization of secretions.
16) Post pyloric feeding in patients with impaired
gastric emptying
17) Risk of VAP associated with early enteral
feeding didn`t translate into ↑ risk of
death,so,early enteral feeding advised.
27. 18) Stress ulcer prophylaxis in high risk
pts(coagulopathy,↑ duration of M/V,h/o
GI bleed.
19) Oral care with 2% chlorhexidine.
20) SELECTIVE CONTANINATION OF
DIGESTIVE TRACT (SDD) :
- consists of nonabsorbable antibio. Against
gram – (tobramycin.polymyxin E) + nystatin/
ampho B for candida administered into GI to
prevent oropharyngeal & gastric colonization.
- SDD reduces incidence of VAP & it‘s the only
strategy that has shown survival benefit
28. - SDD may promote growth of MRSA &
enterococcus,so,its highly recommended to
conduct appropriate surveillance of antibiotic
resistance pattern.
21) Use of probiotics is promising but additional
evidence required.
DIAGNOSIS :
- fever,tachycardia,leucocytosis – too
nonspecific
- tachypnea & consolidation – more specific
- in elderly & immunocomp. Lethargy &
confusion – main symptoms
30. An imaginary vertical line from the sternal notch to
the mouth, passing through the middle of the trachea
should be used as a surface landmark in order to
identify an orientation that could prevent
aspiration of oropharyngeal contents across the
cuff and improve drainage of airway scretions.
- Lateral slight-Trendelenburg position achieved with
the bed tilted few degrees below horizontal
Current Opinion in
Critical Care 2011,
17:57–63
31. - Chest x rays : difficult to interpret,limited
technical quality,misses subtle lung infiltrates.
- D/d for infiltrates :
- cardio/non cardiogenic pulmo. Edema
- atelectasis
- pulmonary contusions
- no radiographic sign has d/g accuracy of >68%
- Air bronchograms or alveolar opacities in pts
without ARDS co-related well with
pneumonia.
- Pleural effusion seen with H.infl>pneumoco
pneumonia
34. CLINICAL PULMONARY INFECTION SCORE
(CPIS) :
CRITERION 0 1 2
tracheal secn. (-) not purulent purulent
x- ray infiltrates NO DIFFUSE LOCALISED
temp °C ≥36.5&≤38.4 ≥38.5&≤38.9 ≥39or≤36
leucocytes ≥4000&≤11000 <4000or>11000 +immature
neutro>50%
PaO2/FiO2 >240 or ARDS ≤240,noARDS
microbio (-) (+)
35. CPIS ≥ 6 is regarded as threshold for
pneumonia but value remains to be validated.
QUANTITATIVE CULTURES OF
ENDOTRACHEAL ASPIRATES MAY HAVE
AN ACCEPTABLE DIAGNOSTIC
ACCURACY.
Current d/g threshold for tracheal aspirates is
10-10^ CFU/ml
― ― ― ― contaminants is
10 CFU/ml
― ― ― ― BAL is 10 CFU/ml
― ― ― ― PBS is 10³ CFU/ml
36. - NON INFECTIOUS CAUSES OF
FEVER/INFILTRATES MIMICKING
NOSOCOMIAL PNEUMONIA :
- chemical pneumonitis
- atelectasis
- pulm embolism
- ARDS
- pulmomary hemorrhage
- lung contusion
- infiltrative tumour
- radiation pneumonitis
- drug reaction
- BOOP
37. MOST RECENT IMPROVEMENTS IN D/G :
* direct antibiogram using E test strips applied
directly to resp samples have proved to be
reliable,effective & anticipate susceptibility by
≥ 48 hrs
* q PCR for mecA gene - for MRSA pneumonia
38. Diagnostic strategies for hospital acquired
pneumonia :
- new or progressive chest infiltrate + atleast 2 of
3 clinical criteria(fever>38°c,leucocytosis or
leucopenia,purulent secretions) represent
beginning of diagnostic procedures
- clinical,non invasive semiquantative strategy
major drawback is high sensitivity of semi
quantative culture results which leads to over
estimation of incidence of nosocomial
pneumonia.
39. Invasive and quantitative culturing strategy
for VAP :
- strongly recommended that d/g sampling of
respiratory tract be obtained before starting
any new antibiotic or changing previous
antimicrobial therapy.
41. STEP I : pt admitted/intubated for> 2
days,with no evident alternative foci of
infection with atleast 2 of 3 criteria :-
- fever > 37.8°c or hypothermia < 36°c
- TLC >12000/µl or <4000/µl
- purulent respiratory secretions
↓
with new infiltrates in chest x ray :
if yes(NP/VAP)||| if no (VAT)
42. STEP II : before initiating new empirical
antibiotics ,collect sample as follows :-
a) expectoration
b) tracheo-bronchial aspirate
c) BAL or mini –BAL
d) PBS
- 2 blood cultures
- pleural fluid sample for parapneumonic
effusion
- legionella/pneumococcal antigens in urine
- CBC/electrolytes/RFT/LFT/procal/ABG/
CRP
43. STEP III : calculate CPIS (TO IMPROVE
OBJECTIVE ASSESMENT OF CLINICAL
PARAMETERS)
TREATMENT :-
most frequently isolated organisms are
s.aureus,pseudomonos f/b enterobacteriacea(e
coli,klebsiella,enterobacter) then gram – as
acinetobacter,stenotrophomonas,burkholdheria &
lastly h influenzae,pneumococcus.
selection of antimicrobial tailored to local
prevelance of pathogens & antimicrobial
patterns of resistance.
46. Risk Factors for Multidrug-Resistant
Pathogens
Antimicrobial therapy in preceding 90 days
Current hospitalization of at least 5 days
High frequency of antibiotic resistance in the community
or in the specific hospital unit.
Presence of risk factors for HCAP:
—Hospitalization for at least 2 days in the preceding 90
days
—Residence in a nursing home or extended care facility
—Home infusion therapy (including antibiotics)
—Chronic dialysis within 30 days
—Home wound care
—Family member with infection involving MDR pathogen
—Immunosuppressive disease and/or therapy
48. Initial Intravenous Adult doses of Antibiotics
Niederman M. et al, AJRCCM, 2005 Antibiotics
Dosage*
Antipseudomonal cephalosporin
Cefepime 1-2g every 8-12h
Ceftazidime 2g every 8h
Carbapenems
Imipenem 500mg every 6h or 1g every 8h
Meropenem 1g every 8h
ß-Lactam/ ß-lactamase inhibitor
Piperacillin-tazobactam 4.5g every 6h
Aminoglycosides
Gentamicin 5-7mg/kg per d
Tobramycin 7mg/kg per d
Amikacin 20mg/kg per d
Antipseudomonal quinolones
Levofloxacin 750mg every d
Ciprofloxacin 400mg every 8h
Vancomycin15mg/kg every 12hs
Linezolid 600mg every 12h
49. NOTE : for legionella → azithro + cipro/levoflox
- For resistant acineto → carbapenem or colistin +
tigecycline
- Nebulised colistin/tobramycin are used as
adjunct to systemic antibiotics in severe gram –
pneumonia,or,resistant bug eliminated only by
high level local drug conc.
- DURATION OF T/T :-
- majority of infections can be treated by 8 days
course,for non fermenting gram( – ) 14 days
- prolonged t/t is required in :
- legionella infection
- biofilms/prosthetic devices
50. - Tissue necrosis,abscess,empyema
- persistence of original infection(perforation,
endocarditis)
FAVOURABLE CLINICAL COURSE :-
- defervescence
- improved PaO2/FiO2
- ↓ CRP in 3-5 days
- third day CPIS < 6
52. - have focussed on ↓ cross transmission,pulm.
aspiration across ETT cuff, ↓ bacterial load in
oropharynx.
HIGHLY EFFECTIVE INTERVENTIONS :
1. SEMIRECUMBENT POSITION
2. SEDATION VACATION
3. DAILY ORAL CLEANSING WITH 2%
CHLORHEXIDINE
4. SUBGLOTTIC SECRETION DRAINAGE
53. FERRER M (clinical infectious d/e 2010) :
- first study that validates 2005 ATS/IDSA
guidelines
- the study demonstrated worse microbial
prediction of 2005 guidelines,in comparison to
previous guidelines,in pts considerd at low risk
for acquiring MDR pathogens & similar low
prediction for fungi.
54. Rather than focusing on VAP,
the new surveillance definition algorithm for
adults broadens the surveillance spectrum to
ventilator associated events(VAE)
A ventilator-associated condition
(VAC) is identified if, after a 2-day period of
stability or improvement on the ventilator, the
patient develops worsening oxygenation
(specific increases in levels of FIO2 or PEEP
over two or more calender years)
55. Infection –related ventilator-associated
complication (IVAC) is identified in pts with
VAC who meet 2 additional criteria of clinical
signs of infection (specifically, defined values
for an abnormal temperature or white
count) and antibiotics prescribed for atleast
4 days. Identification of possible & probable
VAP within IVAC patients is determined by
purulent respiratory secretions and/or
specific laboratory and diagnostic tests. The
new algorithm remains complex and the
CDC is developing additional guidance
for its implementation
56. Several features of the new VAE definition are
important. First, chest radiographs, a required
component in the current definition of VAP,
are no longer used in the definitions of
VAEs (including VAP).Second patients who
are receiving rescue ventilation are excluded.
Third patients must have a period of at
least 2 days of stability or improvent on
mechanical ventilation prior to
worsening.fourth,
VAC (and by extension, IVAC and VAP) is
limited to patients who have have
been mechanically ventilated for atleast
3 calendar days
57. The VAP Surveillance Definition Working Group
recommended removing chest radiography from
the surveillance definition entirely.
The CDC NHSN definition of VAP (and now
VAE, VAC, and IVAC) was developed to enable
surveillance of an important event; the CDC
specifically states that it should not be
used for clinical diagnosis.
AMERICAN JOURNAL OF CRITICAL
CARE, September 2012, Volume 21, No. 5
58. VENTILATOR ASSOCIATED CONDITIONS :-
pt on mechanical ventilation > 2 days
↓
baseline period of stability or improvement,followed
by sustained period of worsening oxygenation
↓
VENTILATOR ASSOCIATED CONDITION(VAC)
↓
general objective evidence of inflammation/infection
↓
INFECTION RELATED VENTILATOR
ASSOCIATED COMPLICATION (IVAC)
↓
59. positive results of microbiological/laboratory testing
↓
possible or probable VAP
April 2013 CDC/NHSN Protocol