Pneumonia in Hospitalized patients CAP HCAP HAP VAPIn the first 48 In CAP with Pneumonia Pneumoniahrs 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
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
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%
Morbidity of VAP• Prolongs ICU stay,• Prolongs mechanical ventilation, and• ↑↑ costs of hospitalization
3. Hospital-Acquired and ICU Pneumonia - Diagnosis
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.
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.
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
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)
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
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.
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
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
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
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
Clinical Features without CXR findings– fever,– leukocytosis,– purulent sputum, and– a positive culture of a sputum or tracheal aspirate → nosocomial tracheobronchitis
Nosocomial tracheo-bronchitis Vs HAP/VAP• Former no mortality• Can progress rarely to HAP/VAP• Contribute for cost of antibiotics
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
Lower respiratory tract specimens• Useful to confirm the diagnosis and• Adjust antibiotic treatment if necessary
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
(B2)Invasive Samples• lower airways can be easily accessed by fibreoptic flexible bronchoscopy.• samples → obtained under direct vision• Possible contamination is less
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
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.
Clinical Vs Microbiological StrategiesThe 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
(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)
(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
(C3) Soluble Triggering ReceptorExpressed 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.