Background: The clinical pulmonary infection score (CPIS) has been advocated to guide both the diagnosis and duration of therapy in ventilator-associated pneumonia (VAP). However, the clinical, physiologic, and radiologic components of the CPIS may be difficult to differentiate from the systemic effects of injury and inflammation, unnecessarily prolonging VAP therapy. This study evaluates the use of CPIS in determining the appropriate duration of antimicrobial therapy for VAP in patients with critical illness and trauma.
Methods: Patients with VAP (≥10 CFU/mL in bronchoalveolar lavage [BAL] effluent) over 6 years were evaluated. Duration of antimicrobial therapy was determined by microbiologic resolution (≤10 CFU/mL) on repeated BAL. Recurrence was defined as >10 CFU/mL on BAL performed within 2 weeks of appropriate therapy. A CPIS of less than 6 was used as a threshold for VAP resolution.
Results: Of the patients with VAP, 1,028 were identified: 523 had community-acquired pathogens (mean CPIS, 6.9), and 505 had hospital-acquired (HA) pathogens (mean CPIS, 6.3). Using a CPIS of less than 6 yielded a sensitivity and specificity of 69% and 51% for community-acquired pathogens and 72% and 53% for HA pathogens, respectively. Antimicrobial therapy would have continued inappropriately in 59% of patients. Overall recurrence was 1%, occurring only with HA pathogens (mean CPIS, 5.9).
Conclusion: CPIS should not be used to determine VAP resolution in patients with critical injury and trauma. It cannot reliably differentiate VAP from the systemic inflammatory response syndrome in the face of confounding clinical factors. Using CPIS to determine appropriate duration of antimicrobial therapy for patients with trauma is costly and could be harmful by unnecessarily prolonging exposure to antibiotics.
Level of evidence: Therapeutic study, level III.