Background: Accurate data on the epidemiology of ventilator-associated pneumonia (VAP) are limited by the lack of standardized criteria for its diagnosis. The difficulties of diagnosis are mostly a results of the following factors: possibility of multiple other causes of systemic inflammatory reactions, pre-existing antibiotic usage in ICU patients and the absence of a standard test to detect and diagnose VAP. The accuracy of clinical criteria (infiltrates on the chest radiograph and 2 of the following: leukocytosis, fever, purulent secretions) for the diagnosis of pneumonia was reasonable with sensitivity of 69% and specificity of 75%. On the other hand, the Clinical Pulmonary Infection Score (CPIS), which combined the clinical signs recorded on the day of the clinical suspicion of VAP to the tracheal aspirate gram stain and culture and Pa02/Fi02 ratio, proved to achieve 72% sensitivity and 85% specificity. This study evaluated the validity of the CPIS and Clinical criteria in the diagnosis of VAP in ICU complex patients and determined the length of ICU stay and mortality rate of patients who had VAP.
Methods: A prospective cohort study was conducted involving patients who had been under mechanical ventilation for more than 48 hours, suspected for VAP and admitted in the ICU complex of the Philippine Heart Center from July 2006 to January 2007. The criteria for diagnosis of VAP using the clinical criteria as well as the CPIS were applied to them. Patients were followed up for occurrence of death until discharge.
Results: Forty patients admitted at ICU complex were enrolled. The mean age of the subjects was 59.6 + 14.8 years. Length of ICU stay was 19.2 + 14.5 days with mean duration of mechanical ventilation of 13.6 + 12.3 days. Sensitivity showed 35.3% and 78.3% on the 1st and 3rd day of referral respectively. Specificity revealed 95.7% and 81.3% on the 1st and 3rd day of referral respectively. Five patients (13%) died, all of them were females. The causes of death were arrhythmia (3 patients) and septic shock ( 2 patients).
Conclusion: This study would still recommend the use of the clinical criteria over CPIS in the diagnosis of VAP. However, VAP continues to be an important challenge to the critical care physician and it is difficult to diagnose accurately, and a high index of suspicion is required.