Table 4.

Causes of therapeutic failure in patients with HAP-VAP. Adapted from Candel et al. [18]

Cause	Recommendation
Inadequate antibiotic treatment	Escalate based on microbiological results.
Sub-therapeutic antibiotic concentrations	Increase antimicrobial dosing. Use extended or continuous antibiotic infusions to optimize PK/PD parameters
New pathogens isolated	Antimicrobial treatment according to microbiological data
Undrained pyogenic focus (i.e., empyema)	Therapeutic drainage
Drug fever	Change antibiotic treatment
A non-infectious illness presenting as HAP	Management as appropriate

PK/PD: pharmacokinetics/pharmacodynamics.