Diagnostic and Prognostic Value of Tracheal Aspirate and Serum Procalcitonin Level in Critically Ill Pediatric Patients with Ventilated Associated Pneumonia

Background: Ventilator-associated pneumonia (VAP) is a frequent nosocomial infection with high mortality and morbidity among critically ill patients. Its diagnosis remains challenging due to the limited reliability of clinical assessments. VAP is suspected in cases of new or progressive pulmonary infiltrates with clinical signs of infection and is confirmed through pathogen identification in lower respiratory tract samples. The utility of procalcitonin (PCT) as a biomarker for VAP diagnosis remains unclear. This study investigates the role of tracheal aspirate procalcitonin in early diagnosis and prediction of VAP. Results: A prospective cohort study was conducted on 50 ventilated pediatric patients in the Pediatric Intensive Care Unit over six months (June–December 2023). Participants (26 females, 24 males; median age: 1.75 years) were divided into VAP and non-VAP groups. PCT levels were measured on day zero and day three of ventilation.In the VAP group, median PCT levels on day three were significantly higher (574.9 ng/mL, IQR: 362–719) than in the non-VAP group (280 ng/mL, IQR: 192.9–555) (p = 0.026), highlighting PCT’s potential as a diagnostic biomarker for VAP. Comparisons of PCT levels in bronchoalveolar lavage (BAL) and serum samples in the VAP group showed no statistically significant difference (median BAL: 2500 ng/mL, IQR: 1231–2500; median serum: 2161 ng/mL, IQR: 1084–2500; p = 0.778).Mortality analysis revealed significantly higher PCT levels on day three in patients who died (574.9 ng/mL, IQR: 353.6–792) compared to those discharged (248.2 ng/mL, IQR: 189.7–453.4) (p = 0.003), suggesting a strong association between elevated PCT levels and mortality risk. Conclusion: Day three PCT levels demonstrated high diagnostic performance in distinguishing VAP from non-VAP cases. Both BAL and serum PCT levels were equally reliable in confirming VAP, showing excellent sensitivity and specificity. Elevated PCT levels were also strongly associated with increased mortality.