VAP Update

1. Ventilator-Associated
pneumonia in the ICU
BY
Dr. Chamika Huruggamuwa
Registrar In Anaesthesia
TH Kandy

3. Introduction
• pneumonia that occurs 48–72 hours or thereafter following
endotracheal intubation,
• characterized by the presence of a
• new or progressive infiltrate,
• signs of systemic infection (fever, altered white blood cell count),
• Changes in sputum characteristics, and
• detection of a causative agent

4. • Early onset VAP is defined as pneumonia that occurs within 4 days
and this is usually attributed to antibiotic sensitive pathogens
• Late onset VAP is more likely caused by multidrug resistant (MDR)
bacteria and emerges after 4 days of intubation

5. Epidemiology
• VAP contributes to approximately half of all cases of hospital-acquired
pneumonia.
• VAP is estimated to occur in 9–27 % of all mechanically ventilated
patients
• VAP is associated with increased intensive care unit stay, patient
ventilator days, and mortality.
• The incidence of VAP can be reduced by many means including the
use of care bundles and modified TTs.

6. • Approximately 50 % of all antibiotics administered in ICUs are for
treatment of VAP.

7. • Independent risk factors for development of VAP are
• male sex,
• admission for trauma
• intermediate underlying disease severity

8. Pathogenesis
complex interplay between the
Endotracheal tube,
Presence of risk factors,
virulence of the invading bacteria
host immunity

9. • The main pathogenic factor in the development of VAP is
biofilm formation within the tracheal tube (TT)
microaspiration of secretions

10. endotracheal tube
violation of natural defense mechanisms
(the cough reflex of glottis and larynx) against
microaspiration around the cuff of the tube

11. • Infectious bacteria obtain direct access to the lower respiratory tract
via:
• (1) microaspiration, which can occur during intubation itself;
• (2) development of a biofilm laden with bacteria (typically Gram-
negative bacteria and fungal species) within the endotracheal tube;
• (3) pooling and trickling of secretions around the cuff ;
• (4) impairment of mucociliary clearance of secretions with gravity
dependence of mucus flow within the airways
•

12. • Pathogenic material can also collect in surrounding anatomic
structures, such as the stomach, sinuses, nasopharynx and
oropharynx, with replacement of normal flora by more virulent
strains
• constantly thrust forward by the positive pressure
• reintubation following extubation increases VAP rates,
• the use of non-invasive positive pressure ventilation has been
associated with significantly lower VAP rates

13. • critically ill patients may have impaired phagocytosis

14. Microbiology
• Type of organism depends on the duration of mechanical ventilation
• Early VAP is caused by
• pathogens that are sensitive to antibiotics,
• whereas late onset VAP is caused by multi-drug resistant and more difficult to
treat bacteria.

15. • Early-onset VAP include Streptococcus pneumoniae (as well as other
streptococcus species), Hemophilus influenzae, methicillin-sensitive
Staphylococcus aureus (MSSA), antibiotic-sensitive enteric Gram-
negative bacilli, Escherichia coli, Klebsiella pneumonia, Enterobacter
species, Proteus species and Serratia marcescens.
• Late VAP are typically MDR bacteria, such as methicillin-resistant S.
aureu (MRSA), Acinetobacter, Pseudomonas aeruginosa, and
extended-spectrum beta-lactamase producing bacteria

16. Diagnosis
• Currently, the diagnosis of VAP is based on a combination of clinical,
Radiological, and Microbiological criteria
• DD
ARDS
pulmonary oedema
pulmonary contusion
Tracheobronchitis
Thromboembolic disease.

17. • no universally accepted, gold standard diagnostic criterion for VAP
• no radiological criteria pathognomonic of VAP and the interpretation
of chest radiographs in ventilated patients is very difficult.
• Single air bronchograms and fissure abutment are highly specific, but
they lack sensitivity

18. • Invasive and non-invasive sampling techniques are used to Obtain
microbiological specimens to diagnose VAP.
• Broncho Alveolar Lavage (BAL) mini BALs
• Protected specimen brushings (PSB)
• Tracheal aspirates
• Th e American Th oracic Society (ATS) and the
• Infectious Diseases Society of America (IDSA

19. BAL gold standard over others,,,,, however
• It cannot guarantee sampling from the area of the lung most affected,
the sensitivity of this test is low, although the specificity is quite high
(significant false-negative rate).
• CPIS -clinical, physiological, microbiological and radiographic
evidence

21. • Scores can range between zero and 12 with a score of ≥ 6 showing
good correlation with the presence of VAP
• Despite the clinical popularity of the CPIS, debate continues regarding
its diagnostic validity.

22. • The Johannson criteria
• The HELICS criteria
• The United States Centre for Disease Control (CDC) definition

23. Treatment
• antibiotic depends on the duration of mechanical ventilation.
• Late onset VAP (> 4 days) broad spectrum antibiotics
• Early onset (≤ 4 days) limited spectrum antibiotics

24. • The usual duration of treatment for early onset VAP is 8 days and
longer in the case of late-onset VAP or if MDR organisms are
suspected or identified
• Despite therapy, if no response is observed, it may be prudent to
reconsider the diagnosis, reassess the organism being treated or
search for other reasons for signs and symptoms.

25. Prevention
• The role of care bundles
A care bundle refers to a group of evidence-based interventions related
to a particular condition which when applied together significantly
improves patient outcome.

26. TT modification
• TT cuff design to prevent microaspiration.
Cuff pressure control
• cuff pressure <20 cm H2O favors increased passage of secretions
between the cuff and the wall of the trachea, while >30cmH2O may
cause tracheal mucosal damage.

27. Subglottic secretion drainage
A meta-analysis of 13 randomized controlled trials showed that
subglottic secretion drainage was effective at reducing VAP rates, also
reducing the time to onset of first VAP, reduced duration of mechanical
ventilation, and reduced ICU LOS.

28. TT cuff design
high volume–low pressure cuff Vs A tapered cuff shape

29. TT coating
Silver-coated TT or a standard TT
chlorhexidine and titanium dioxide.
Significant reduction in VAP rates
NO Reduction in ICU LOS or duration of ventilation
NASCENT TRIAL

30. Nebulized gentamicin
• Nebulized gentamicin attained a higher concentration within the TT
and there was a lower incidence of biofilm formation

31. Kinetic therapy
Mucociliary clearance is inhibited by immobility.
• Mechanical rotation of patients with 40° turns achieves more
significant clearance of secretions than current standard therapy of 2
hourly turns
Lower the
incidence of VAP
No effect on duration
of ventilation, LOS, or
mortality.
Requires specialist equipment
and has been
associated with significant
complications such as
intolerance to
rotation, unplanned
extubations, loss of vascular
access, and
arrhythmias.

32. Care of airway equipment
• Studies have shown that TT colonization and biofilm formation begins
within 24 h of intubation.
Reducing biofilm formation can be achieved by,
Strict attention to hand hygiene when handling the TT,
closed-circuit suction systems,
use of heat and moisture exchangers,
limiting ventilator tube changes to whenever they are soiled,

33. Feeding
• early establishment of enteral feeding is of benefit to critical care
patients.
• reflux and aspiration of gastric contents is the main cause of VAP.
• post-pyloric feeding may reduce the incidence of VAP.

34. Intubation-related events
Reducing the duration of intubation with the use of sedation
holds and weaning protocols
reducing unplanned extubations
minimizing re-intubation have also been shown to reduce VAP
incidence

36. The major goals of VAP management
early, appropriate antibiotics in adequate doses followed by de-
escalation based on microbiological culture results and the clinical
response of the patient.
Antimicrobial stewardship programs involving pharmacists, physicians
and other healthcare providers optimize antibiotic selection, dose, and
duration to increase efficacy in targeting causative pathogens and allow
the best clinical outcome