Individualized Antibiotic Therapy in Patients with Ventilator-Associated Pneumonia in the Intensive Care Unit

Background The optimal duration of treatment for ventilator-associated pneumonia (VAP) remains controversial. Although current guidelines recommend 7-8 days of therapy, many patients receive treatment for 14 days or longer. The parameters and criteria that may allow treatment duration to be shortened and individualized are not clearly defined. In this study, we aimed to compare the epidemiological, clinical, radiological, and laboratory characteristics of two groups of patients diagnosed with VAP-those who received 7-10 days of treatment and those who received longer courses-in order to establish criteria for individualized short-term therapy in appropriate patients. Methods This retrospective study included patients diagnosed with VAP in the intensive care unit (ICU) of our hospital between January 1, 2015 and June 30, 2018. A total of 147 VAP episodes in 111 patients who met the inclusion and exclusion criteria were evaluated. Patients were divided into two groups according to treatment duration: the short-term treatment group (STTG; 7-10 days) and the long-term treatment group (LTTG; >10 days). Results Among the 147 VAP episodes, 35 episodes in 30 patients received 7-10 days of antibiotic therapy, while 112 episodes in 81 patients received >10 days of treatment. Baseline demographic characteristics and clinical severity scores on day 1 were statistically similar between the two groups (p>0.05). The most frequently isolated microorganisms in both groups were Acinetobacter baumannii and Pseudomonas aeruginosa . The following variables were identified as distinguishing criteria for short-term treatment: absence of fever on day 5, procalcitonin (PCT) ≤0.5 μg/L on day 5, C-reactive protein (CRP) <15 mg/dL on day 5, PaO₂/FiO₂ ratio >300 mmHg on day 5, CPIS ≤4 on day 5, absence of bacteremia, and appropriate empirical therapy. When ≥4 of these criteria were present, the area under the curve (AUC) was 0.712, with sensitivity 91.4%, specificity 50.9%, positive predictive value (PPV) 36.8%, and negative predictive value (NPV) 95.0%. When PaO₂/FiO₂ >300 mmHg on day 5 was required as one of the ≥4 criteria, the AUC increased to 0.804, with sensitivity 85.7%, specificity 75%, PPV 51.7%, and NPV 94.4%. Conclusions In patients with VAP who receive appropriate empirical therapy and have no bacteremia, short-term treatment may be considered in the presence of early clinical and laboratory response. Fever, procalcitonin, CRP, PaO₂/FiO₂ ratio, and CPIS values on day 5 of treatment may serve as practical criteria to guide individualized therapy duration.