What is the definition of hospital-acquired pneumonia (HAP)?

Definition of Hospital-Acquired Pneumonia (HAP)

Hospital-acquired pneumonia (HAP) is defined as a lung infection that develops after 48 hours or more of hospitalization and was not present or incubating at the time of admission. 1

Key Diagnostic Criteria

HAP diagnosis requires:

• New or progressive radiographic infiltrates on chest imaging
• Plus at least two of the following:
  • Fever
  • Leukocytosis or leukopenia
  • Purulent secretions 1

Classification and Types

HAP is the second most common nosocomial infection after bloodstream infections and the most common infection acquired in intensive care units 1, 2. It can be further classified into:

1. Ventilator-Associated Pneumonia (VAP):

   • A subset of HAP that occurs in mechanically ventilated patients
   • Develops more than 48-72 hours after endotracheal intubation
   • Can affect up to 12% of ventilated children 2, 1

2. Healthcare-Associated Pneumonia (HCAP):

   • Includes patients who were hospitalized in an acute care hospital for two or more days within 90 days prior to infection
   • Residents of nursing homes or long-term care facilities
   • Patients who received intravenous antibiotic therapy, chemotherapy, or wound care within 30 days prior
   • Patients who attended a hospital or clinic for hemodialysis 1

Distinguishing Features from Other Pneumonias

• Community-Acquired Pneumonia (CAP): Defined as pneumonia in a previously healthy individual caused by an infection acquired outside the hospital 2
• HAP: Develops after 48 hours of hospitalization, not present at admission 2, 1, 3

Clinical Significance

• HAP is associated with an approximate mortality rate of 20%
• Attributable mortality is estimated between 5-13% 1
• Significantly contributes to increased healthcare costs due to:
  • Increased antibiotic use
  • Extended ICU stays
  • Prolonged hospitalization 3

Common Pitfalls in HAP Management

• Diagnostic challenges:

  • Differentiating colonization from true infection
  • Overdiagnosis leading to unnecessary antibiotic use
  • Delayed diagnosis resulting in delayed appropriate therapy 1

• Treatment errors:

  • Inadequate initial antimicrobial coverage
  • Failure to obtain cultures before starting antibiotics
  • Treating colonization rather than infection
  • Failure to de-escalate therapy when appropriate 1

HAP requires prompt recognition and appropriate management to reduce morbidity and mortality. The definition based on pneumonia developing after 48 hours of hospitalization serves as the cornerstone for identification and subsequent management strategies.