Approach to managing patients with VAP who are not improving

In patients with ventilator-associated pneumonia (VAP), if signs and symptoms do not improve as expected with appropriate antibiotic therapy, reassess the diagnosis before escalating antibiotic therapy. Also ensure airway clearance strategies are optimised.

Complications of pneumonia and differential diagnoses to consider are listed in Considerations in patients with VAP who are not improving on empirical antibiotic therapy. Review the results of previous diagnostic tests (eg nose and throat swabs, sputum samples). Further imaging studies such as a repeat chest X-ray or chest computed tomography (CT) scan may be considered to investigate for complications or alternative diagnoses. Consider testing for an unrecognised immune system disorder, such as HIV infection. For patients with immune compromise, consider more extensive investigations for a broader range of pathogens.

Seek expert advice on whether to adjust empirical antibiotic therapy in patients with VAP who are not improving.

Figure 1. Considerations in patients with VAP who are not improving on empirical antibiotic therapy

If a patient is not improving with empirical antibiotic therapy for VAP, consider:

  • complications of pneumonia – consider lung abscess or parapneumonic effusion and empyema
  • noninfective causes – such as:
    • exacerbations of heart failure or COPD
    • acute respiratory distress syndrome
    • pulmonary embolus
  • respiratory viruses that can cause pneumonia and pneumonitis such as influenza, parainfluenza, human metapneumovirus, coronavirus (eg SARS-CoV-2), RSV – if suspected, perform nose and throat swabs for nucleic acid amplification testing (eg PCR)
  • Aspergillus species, in particular, Aspergillus fumigatus complex – because of its high mortality, empirical therapy may be warranted in patients with other risk factors for secondary fungal pneumonia caused by A. fumigatus complex (eg concurrent viral pneumonia with SARS-CoV-2 or influenza, corticosteroid therapy)Boyd, 2022Chen, 2022Fumagalli, 2022White, 2021. However, if fungal species are identified on lower respiratory tract culture, this can represent colonisation in ventilated patients and those with pre-existing lung disease, so treatment is not always required. Nucleic acid amplification testing (eg PCR) or biomarkers such as plasma and bronchiolar lavage (BAL) galactomannan may be used for diagnosis, although specificity and sensitivity are not well establishedAberegg, 2021Loughlin, 2020Torres, 2020. See Aspergillosis for management
  • unusual bacterial pathogens, such as Legionella species, Nocardia species or Mycobacterium tuberculosis
  • anaerobes not adequately treated with standard empirical therapy – especially in patients with severe periodontal disease or putrid sputum, in whom infection with specific anaerobes (eg Bacteroides or Prevotella species) is more likely. If the patient is being treated with a regimen without adequate activity against these anaerobes (eg ceftriaxone; cefotaxime; cefepime; ciprofloxacin plus vancomycin), seek expert advice on modifying therapy
  • undiagnosed immunodeficiency with opportunistic infection (eg CMV infection, PJP) – consider whether pneumonia is the presenting feature of an undiagnosed immunodeficiency
  • a broader range of pathogens in patients with immune compromise, such as Aspergillus species, Cryptococcus species, CMV, or Pneumocystis jirovecii (PJP) – see Aetiology of VAP in patients with immune compromise for more information.
Note:

CMV = cytomegalovirus; PCR = polymerase chain reaction; PJP = Pneumocystis jirovecii pneumonia; RSV = respiratory syncytial virus; SARS-CoV-2 = severe acute respiratory syndrome coronavirus 2; VAP = ventilator-associated pneumonia