Hospital-acquired pneumonia (HAP) is defined as pneumonia occurring ≥48 hours after admission and excluding any infection that is incubating at the time of admission.
Ventilator-associated pneumonia (VAP) is described as pneumonia occurring >48-72 hours after endotracheal intubation and within 48 hours after removal of endotracheal tube.
Early-onset HAP or VAP is the pneumonia occurring within the first 4 days of hospitalization that may be cause by antibiotic-sensitive bacteria that usually carries a better diagnosis.
Late-onset HAP or VAP is the pneumonia occurring after ≥5 days. It is likely caused by multidrug-resistant pathogens associated with increased mortality and morbidity.


  • The clinical approach to define pneumonia makes use of clinical evidence & radiographic findings
  • Clinical Pulmonary Infection Score (CPIS) is used to quantify clinical, radiographic, microbiologic & physiological findings
    • A threshold score of >6 leads to a diagnosis of hospital-acquired pneumonia (HAP); has a sensitivity of 77% & specificity value of 42%
    • May be useful in selecting patients for short-course antibiotic therapy & monitoring of response to treatment


CURB65 Scoring System for Mortality Risk Assessment
  • May be used as a prognostic baseline for patients diagnosed w/ hospital-acquired pneumonia
Prognostic Features (1 point for each feature present)
  • Confusion (abbreviated Mental Test score ≤8 or new disorientation)
  • Increased blood urea nitrogen (≥7 mmol/L)
  • Increased respiratory rate (≥30 breaths/min)
  • Decreased blood pressure (≤90/60 mmHg)
  • ≥65 years old
  • 0 or 1: Low risk (<3% mortality risk)
  • 2: Moderate risk (3-15% mortality risk)
  • 3-5: High risk (>15% mortality risk)


  • Thorough history & physical exam are performed to define the severity of the pneumonia
  • They can elicit presence of specific conditions that can have an impact on the likely pathogens
  • Exclude other potential sources of infection

Laboratory Tests

  • Should be collected before antibiotics are started or changed
  • Blood
    • Two sets from separate sites
    • If blood cultures (BC) isolate a pathogen, other sites of infection will need to be excluded
  • Sputum, pleural fluid
  • Endotracheal or transtracheal aspirate
Invasive Microbiologic Techniques
  • Usually confined to intubated patients
  • Invasive procedures [eg bronchoscopy w/ protected specimen brushing (PSB) &/or bronchoalveolar lavage (BAL)]
  • Etiologic pathogen is determined if a specimen contains organism(s) above a predetermined threshold concentration
Arterial Blood Gas or Oximetry
  • Generally measured in all patients to determine the severity of illness & the need for supplemental O2 or mechanical ventilation
Other Laboratory Tests
  • Complete blood count (CBC), serum electrolytes, renal & liver function
  • A baseline C-reactive protein may be obtained for assessment of response to therapy 48-72 hours after admission
  • Not useful for determining the etiologic organism
  • May be useful to document presence of organ dysfunction to assist in determining the severity of illness


Chest X-ray (CXR)
  • Both posterior-anterior (PA) & lateral views are recommended
  • Helps to identify disease severity & presence of complications (eg effusion, cavitation)

Clinical evidence that new or progressive infiltrate is consistent of pneumonia

  • At least 2 of the following should be present:
    • Fever >38°C
    • Purulent sputum
    • Leukocytosis [WBC >12,000 cells/mm3 (12x109 cells/L)] or leukopenia [WBC <4,000 cells/mm3 (4x109 cells/L)]
  • There is high sensitivity even if only 1 criterion is used, but low specificity is noted for ventilator-associated pneumonia (VAP)
Digital Edition
Asia's trusted medical magazine for healthcare professionals. Get your MIMS Respirology - Malaysia digital copy today!
Editor's Recommendations
Most Read Articles
22 May 2017
Chronic obstructive pulmonary disease (COPD) is currently the 10th commonest cause of death in Singapore, with a disease burden of 5.9 percent according to a 2015 population-based survey (EPIC-Asia survey) in Singapore. Pearl Toh spoke with Dr Augustine Tee, chief and senior consultant of the Department of Respiratory and Critical Care Medicine at Changi General Hospital (CGH) in Singapore, on how COPD is often underdetected in the primary care population as symptoms are not specific and diagnosis requires a combination of clinical risk factors, symptoms and spirometry testing.
15 Aug 2017
New drug applications approved by US FDA as of 1 - 15 August 2017 which includes New Molecular Entities (NMEs) and new biologics. It does not include Tentative Approvals. Supplemental approvals may have occurred since the original approval date.
04 Aug 2017
Chronic obstructive pulmonary disease (COPD) is the fourth cause of global mortality, with experts predicting a potential future rise in the prevalence rates of COPD. 
11 May 2016

In conjunction with World Asthma Day which falls on 3rd May 2016, MIMS Doctor speaks to a renowned respiratory medicine specialist, Dato' Dr. Hj Abdul Razak Abdul Muttalif, regarding the chronic airway disease.