Early antibiotic exposure in mechanically ventilated acute brain-injured patients: A single-centre observational...

Acute brain injury (ABI) is a common cause of intensive care unit (ICU) admission. Patients with ABI often require endotracheal intubation and prolonged mechanical ventilation, which places them at an increased risk of nosocomial infections. As a result, intravenous (IV) antibiotic exposure in this cohort is likely to be common, although its use has not been systematically reported.

The objective of this study was to determine the proportion of ABI patients receiving IV antibiotics within the first 14 days in the ICU, to describe the nature of this exposure, and to evaluate any association with 30-day in-hospital mortality.

A Retrospective, single-centre observational cohort study of mechanically ventilated adult ABI patients admitted to the ICU was conducted between October 2018 and June 2023. Patient demographics, clinical characteristics, antibiotic exposure, microbiological findings, and outcomes were collected from institutional databases.

Of the 1098 ICU patients in the study, 805 (73%) received at least one IV antibiotic within the first 14 days. Among these, 196 (24%) received prophylactic antibiotics only, 257 (32%) received therapeutic antibiotics only, and 352 (44%) received both. Cefazolin was the primary prophylactic agent (172/196; 87.5%), while ceftriaxone was the most common therapeutic antibiotic (113/257; 44.1%). Median durations of prophylactic and therapeutic courses were 2 days (interquartile range:IQR 1-3) and 5 days (interquartile range:IQR 3-8), respectively. Only 135 of 609 patients receiving therapeutic antibiotics (22%) returned positive cultures, with Enterobacteriaceae (48/135; 35.6%), Staphylococcus (33/135; 24.4%), and non-fermenters (17/135; 12.6%) being the most common. Prophylactic-only use was associated with lower 30-day in-hospital mortality (hazard ratioHR: 0.30, p = 0.015), whereas therapeutic antibiotics without prophylaxis were associated with increased risk-adjusted 30-day in-hospital mortality (hazard ratio:HR 1.85, p = 0.048).

Antibiotic exposure is common in mechanically ventilated ABI patients, with ceftriaxone frequently employed as the first-line therapeutic agent. In the adjusted analysis, prophylactic antibiotic administration was found to be associated with a survival benefit.