Health Care-Associated Pneumonia - HCAP

Diagnosis

Indications for Testing

  • New infiltrate on chest x-ray in hospitalized patient
  • New fever with cough
  • New deterioration in mechanically ventilated patient

Laboratory Testing

  • CBC with differential – leukocytosis and differential left shift; however, results may be normal or even demonstrate leukopenia
  • Gram stain and culture – sputum
    • Conscious patient – may need to induce sputum; sputum is critical because organisms are more often resistant to standard antimicrobial therapy
    • Ventilator dependent – bronchoalveolar lavage (BAL) or protected specimen brush (PSB) 
      • Confirmed if ≥103 colony-forming units (CFU)/mL for (PSB) or ≥104 CFU/mL for BAL
  • Arterial blood gas or oximetry – decreased partial pressure of oxygen in arterial blood (PaO2) saturation

Imaging Studies

  • Chest x-ray
    • Infiltrates, effusion, atelectasis, cavities
    • May appear unchanged, particularly in patients with preexisting infiltrates
  • CT scan 
    • More sensitive than x-ray
    • Difficult to perform in mechanically ventilated patients

Differential Diagnosis

Clinical Background

Health care-associated pneumonia (HCAP), including hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP), are associated with morbidity and mortality and create a substantial economic burden.

Definitions

  • HCAP – pneumonia that develops in patients
    • After hospitalization for ≥2 days
    • Residing in nursing home or long-term care facility
    • Attending a hospital or hemodialysis clinic
    • Receiving immunosuppressive therapy or wound care within 30 days of infection
  • HAP – pneumonia occurring ≥48 hours post-hospital admission
  • VAP – pneumonia occurring >48-72 hours postintubation

Epidemiology

  • Incidence
    • HAP – 5-10/1,000 hospitalizations
    • VAP – 7-16/1,000 ventilator days
  • Age – increased incidence with older age

Organisms

Risk Factors

  • HCAP
    • Hospitalization ≥2 days within the past 90 days
    • Resident in nursing home
    • Home infusion therapy in past 30 days
    • Long-term dialysis in past 30 days
    • Home wound care in past 30 days
    • Family member with multi-drug resistant infection
  • VAP (ICU factors)
    • Ventilator use
    • Administration of H2 blockers
    • Nasogastric tube
    • Tracheostomy
    • >60 years of age
    • Use of paralytics
    • Coma
    • Acute respiratory distress syndrome (ARDS)
    • Admitting diagnosis of burn or trauma
    • Intracranial pressure monitoring

Pathophysiology

  • Usually involves aspiration of oropharyngeal and gastric contents

Clinical Presentation

  • Altered consciousness and fever may be only symptoms
  • Purulent sputum, cough, crackles, rhonchi, wheezing
  • New infiltrate on chest x-ray
  • May present with overt signs and symptoms of sepsis – hypotension, tachycardia or septic shock
  • Complications
    • Sepsis
    • Pleural effusion
    • Pneumothorax
    • Pneumatoceles
    • Pneumomediastinum
    • ARDS
    • Multiorgan failure

Treatment

  • Antibiotics
    • Necessary to cover more virulent pathogens that tend to be the etiology in these pneumonias

Prevention

  • CDC guidelines for preventing health care-associated pneumonia
  • Noninvasive positive pressure ventilation to avoid intubation
  • Frequent draining of condensate in ventilator circuit to avoid colonization
  • Selective gut decontamination to reduce aspiration risk
    • Not popular in the U.S. due to fear of widespread resistance
  • Orotracheal intubation instead of nasotracheal to remove risk of sinusitis
  • Incentive spirometry postoperatively in nonventilated patients to reduce risk of atelectasis
  • Hand-hygiene measures in all hospital staff and visitors

Indications for Laboratory Testing

  • Tests generally appear in the order most useful for common clinical situations
  • Click on number for test-specific information in the ARUP Laboratory Test Directory
Test Name and Number Recommended Use Limitations Follow Up
Respiratory Culture and Gram Stain 0060122
Method: Stain/Culture/Identification

Identify organism causing pneumonia

   
CBC with Platelet Count and Automated Differential 0040003
Method: Automated Cell Count/Differential

Aid in determining presence of infection

   
Bronchoscopy Culture and Gram Stain 0060700
Method: Quantitative Culture/Identification

Differentiate ventilator pneumonia from colonization

Includes gram stain testing