1. Pneumonia in hospitalized
patients
Diagnostic Strategy
Dr. Mahen Kothalawala MBBS, Dip in Micro, MD, MPH(NZ),
Consultant Clinical Microbiologist
Teaching Hospital Kandy
Offsite consultant for TH Kegalle, DGH Matale, BH Nawalapitiya and Sirimawo Bandaranayake Specialized Hospital for
Children

2. 1.
Introduction

3. Pneumonia in Hospitalized patients
CAP HCAP HAP VAP
In the first 48 In CAP with Pneumonia Pneumonia
hrs of hospital recent contact developing developing
admission with health after 48 to 72 after 48 of
care system hrs after intubation
admission 1. Early onset
2. Late onset

4. 2.
HAP/VAP Burden

5. Ventilator-associated pneumonia
(VAP) burden
• Common in Critical Care Unit
• Estimated 8 to 20% of ICU patients
• Occur up to 27% of mechanically ventilated
patients
• Pts intubated > 24hrs are 6 to 21 times more
likely to develop VAP than those intubated
<24hrs

6. Mortality
• Mortality rates
– range from 20 to 50%
• Some studies >70% (when caused by Multi
resistant organisms)
– Attributable mortality → difficult to quantify – due
to confounders
– But, VAP ↑mortality of the underlying disease by
about 30%

7. Morbidity of VAP
• Prolongs ICU stay,
• Prolongs mechanical ventilation, and
• ↑↑ costs of hospitalization

8. 3. Hospital-Acquired and ICU
Pneumonia - Diagnosis

9. HAP/VAP
• “There is no doubt that the diagnosis and
management of VAP remains one of the most
controversial and challenging topics in
management of critically ill patients.”
(Chan C, Chest 2005;127:425 )
• The diagnosis of hospital-acquired pneumonia
is complex.

10. Diagnostic Testing for HAP/VAP
• Diagnostic tests are ordered for two
purposes:
• To define
– whether a patient has pneumonia
– etiologic pathogen when pneumonia is present.

11. Diagnosis of HAP/VAP
• A. Clinical Strategy
– A radiographic infiltrate, plus the presence of at least one of the
three clinical data
– Clinical pulmonary infection score (CPIS)
• B. Microbiological Strategy
– Non-invasive Methods
• Blood Cultures:
• Sputum Samples and Tracheal Aspirates:
– Invasive Sampling Methods
• Protected Specimen Brush (PSB):
• Bronchoalveolar Lavage (BAL):
• C. Usage of other inflammatory markers to support Δof
HAP/VAP
– CRP
– Procalcitonin
– sTREM 1

12. A. Clinical Strategy
(A1) A radiographic evidence of infiltrate, plus the
presence of at least one of the three clinical data
• new onset of fever,
• purulent sputum,
• leukocytosis
(A2) Clinical pulmonary infection score (CPIS)

13. A single clinical finding VS multiple
features
• Presence of radiographic infiltrate with
• one clinical feature
– fever,
– leucocytosis, or
– change of secretions – increase in volume or
purulent
• have high sensitivity but low specificity
(especially for VAP).
• Combination may improve specificity

14. Comparison clinical criteria with PM
findings
• Presence of chest infiltrates, plus two of three
clinical criteria resulted
– 69% sensitivity
– 75% specificity
• Using three clinical variables → sensitivity
declined
• One variable → decline in specificity.

15. A2. Clinical pulmonary infection score (CPIS)
• A Tool with 6 easily obtained variables
– body temperature,
– white blood cell count,
– quantity and purulence of tracheal secretions,
– chest radiograph,
– oxygenation, and,
– bacterial growth in lower respiratory tracheal
secretions

16. Table 1. Clinical Pulmonary Infection Score (CPIS)
Total Day #0 = _________ Total Day #3 = _________
Score Score
Day 0 Day 3
Temperature, ºC Temperature, ºC
³38.5º - 38.9º = 1 point 38.5º - 38.9º = 1 point
³39.0º - 36.0º = 2 points 39.0º - 36.0º = 2 points
Blood leucocytes, mm-3 Blood leucocytes, mm-3
<4.000 or >11.000 = 1 point <4.000 or >11.000=1 point
50% band forms = add 1 point 50% band forms = add 1 point
Tracheal secretions Tracheal secretions
Presence of non-purulent tracheal Presence of non-purulent tracheal
secretions = 1 point secretions = 1 point
Presence of purulent tracheal secretions Presence of purulent tracheal
= 2 points secretions = 2 points
Oxygenation: PaO2/FIO2 Oxygenation: PaO2/FIO2
>240 or ARDS = 0 point >240 or ARDS = 0 point
< 240 and no ARDS = 2 points < 240 and no ARDS = 2 points
Pulmonary radiography Pulmonary radiography
No infiltrate = 0 point No infiltrate = 0 point
Diffuse or patchy infiltrate = 1 point Diffuse or patchy infiltrate = 1 point
Localized infiltrate= 2 points Localized infiltrate= 2 points
Microbiological Data Microbiological Data
Pathogenic bacterial cultured in rare or Pathogenic bacterial cultured in rare
hight quantity or no growth = 0 or hight quantity or no growth =
point 0 point
Pathogenic bacterial cultured in Pathogenic bacterial cultured in
moderate or heavy quantity = 1 moderate or heavy quantity = 1
point point
Same pathogenic bacterial seen Same pathogenic bacterial
seen on Gram stain = add 1
on Gram stain = add 1 point
point

17. Clinical pulmonary infection score
(CPIS)
• Score ranges from 0 to 12
• > 6/12 would correlate well →
microbiologically confirmed HAP.
• CPIS → used to select patients to treat safely
with short-course antibiotic.
• Some have shown that the score may lack
sensitivity and specificity to establish → ΔHAP

18. Pitfalls of CPIS
• Observers variability
• Microbiological results are often delayed (48hrs)
/ Not available always
• Practical Approach – Usage with modifications
• Modifications of CPIS
– Use of Gram Stain where results available in one day
– Eliminate the culture report and take same cut off

19. Clinical Features without CXR findings
– fever,
– leukocytosis,
– purulent sputum, and
– a positive culture of a sputum or tracheal aspirate
→ nosocomial tracheobronchitis

20. Nosocomial tracheo-bronchitis Vs
HAP/VAP
• Former no mortality
• Can progress rarely to HAP/VAP
• Contribute for cost of antibiotics

21. B. Microbiological Strategy
• Aim – to identify the specific pathogen by
culture
– (B1) Non respiratory culture
• Blood
• Pleural fluid
– (B2) Lower respiratory culture (From LRT)
• Invasive Method
– BAL
– PSB
• Non Invasive method
– Tracheal secretions

22. Lower respiratory tract specimens
• Useful to confirm the diagnosis and
• Adjust antibiotic treatment if necessary

23. Non invasive Method
Tracheal Aspirates:
• Gram stain and culture of TA- may provide
relevant microbiological information,
• Interpret with caution - as they not distinguish
colonization from distal infection/pneumonia.
• In intubated patients, as TA is obtained from
deep of lung has higher diagnostic value

24. (B2)Invasive Samples
• lower airways can be easily accessed by
fibreoptic flexible bronchoscopy.
• samples → obtained under direct vision
• Possible contamination is less

25. Protected Specimen Brush (PSB):
• Threshold to discriminate colonization and
infection is 103 cfu/mL
• PSB → high sensitivity (>70%) and specificity
(80-90%) for infection.
• Prior antibiotic Rx ↓detection sensitivity

26. Bronchoalveolar Lavage (BAL):
• Has appropriate Sensitivity and specificity to
Δ HAP
• Cutoff >104 cfu/mL
• *> 2% of bacteria embedded in PMN or mφ
cells in centrifuged BAL fluid → have a high
specificity for infection (approaching 100%)
• Antibiotic treatment readily ↓ intracellular
bacterial count.

27. Clinical Vs Microbiological
Strategies
The Clinical Approach Microbiological Approach
• Overly (too) sensitive • Requires Invasive
• Patients treated with procedures to achieve
antibiotics when a non-
infectious process is acceptable sensitivity and
responsible for the clinical specificity
findings. Such as
– congestive heart failure, • Non invasive- Isolation false
– atelectasis, positive pathogens
– pulmonary thrombo embolism,
– pulmonary drug reactions,
• Negative results- highly
– pulmonary hemorrhage, or significant as it coming
– ARDS below the respiratory tract
• Requires good quality X-rays

28. 3.
Supportive tests

29. (C1) CRP
• Inflammatory mediator
• Released from the liver after stimulation by the
cytokine IL-6
• Produced as a part of SIRS/Sepsis.
• Reliable marker for infection and sepsis.
• CRP may have prognostic value in HAP.
– ↑ CRP after 4 days of treatment noticed in non-
survivors (marker of poor outcome)

30. (C2) Procalcitonin
• PCT increase in
– invasive bacterial infections,
– viral infections or
– autoimmune diseases.
• Predict progression to severe sepsis and shock.
• been described as a prognostic marker in VAP
• ↑ levels in first week – worse outcome

31. (C3) Soluble Triggering Receptor
Expressed on Myeloid Cells (sTREM-1):
• sTREM-1 is a mediator the acute inflammatory
response
• ↑ sTREM-1 in sepsis and shock - useful to
monitor
• ↑ sTREM-1 in BAL fluid noticed in VAP
– Cut off of >5 pg/mL ( Sensitivity 98% and
Specificity 90%)
• s-TREM-1 in alveolar samples is marker of
HAP,
• Draw back – requires BAL.

32. Flow chart to diagnose
VAP

34. Treatment – Ask the
expert

35. • END