Antibiotic Use Among Children Requiring Respiratory Support in Intensive Care Unit (ICU) from Sofia, Bulgaria: A Single-Center Retrospective Experience

Antibiotic use in critically ill children requiring respiratory support remains controversial, particularly in the absence of standardized guidelines for patients managed with non-invasive ventilation (NIV). Evidence in this area remains limited, and real-world data are therefore valuable. <b>Objective:</b> This retrospective single-center study aimed to describe antibiotic prescribing patterns and infectious outcomes in pediatric patients admitted to the intensive care unit (PICU) with respiratory failure, according to the type of respiratory support. <b>Methods:</b> Children aged 0-17 years admitted between January 2021 and February 2025 who required oxygen supplementation, NIV, or invasive mechanical ventilation (IMV) were included. Demographic characteristics, underlying conditions, infectious complications, antibiotic exposure, length of PICU stay, and outcomes were analyzed using descriptive statistics and univariate comparisons. <b>Results:</b> Eighty-nine patients were included. Ventilator-associated pneumonia (VAP) occurred exclusively in patients receiving IMV, and infection complications were observed more in this group compared to those receiving NIV (<i>p</i> = 0.005). <i>Pseudomonas aeruginosa</i> was the most frequently isolated pathogen. Antibiotics were administered in 82% of patients, with no significant association between the respiratory support and initiation of antibiotic therapy (<i>p</i> = 0.195). A higher number of antibiotics was administered in patients receiving IMV compared with those receiving oxygen therapy alone. <b>Conclusions</b>: Antibiotic use in children requiring respiratory support in the PICU was common and appears to be driven primarily by underlying disease and illness severity rather than by the ventilation modality alone. Infections specific to invasive ventilation, such as VAP, were more frequent in patients receiving IMV, while infection-related outcomes in non-invasive groups should be interpreted cautiously due to differences in diagnostic definitions. These findings are descriptive and hypothesis-generating and highlight the need for prospective multicenter studies to create evidence-based antibiotic stewardship strategies in pediatric critical care.