Preventive Antibiotics and Delayed Cerebral Ischaemia in Patients with Aneurysmal Subarachnoid Haemorrhage Admitted to the Intensive Care Unit.

Introduction: Delayed cerebral ischemia (DCI) is an important contributor to poor outcome after aneurysmal subarachnoid haemorrhage (aSAH). Development of DCI is multifactorial, and inflammation, with or without infection, is one of the factors independently associated with development of DCI and poor outcome. We thus postulated that preventive antibiotics might be associated with a reduced risk of DCI and subsequent poor outcome in aSAH patients.

Methods: We performed a retrospective cohort-study in intensive care units (ICU) of three university hospitals in The Netherlands. We included consecutive aSAH patients with minimal ICU stay of 72 h who received either preventive antibiotics (SDD: selective digestive tract decontamination including systemic cefotaxime or SOD: selective oropharyngeal decontamination) or no preventive antibiotics. DCI was defined as a new hypodensity on CT with no other explanation than DCI. Hazard ratio's (HR) for DCI and risk ratio's (RR) for 28-day case-fatality and poor outcome at 3 months were calculated, with adjustment (aHR/aRR) for clinical condition on admission, recurrent bleeding, aneurysm treatment modality and treatment site.

Results: Of 459 included patients, 274 received preventive antibiotics (SOD or SDD) and 185 did not. With preventive antibiotics, the aHR for DCI was 1.0 (95% CI 0.6-1.8), the aRR for 28-day case-fatality was 1.1 (95% CI 0.7-1.9) and the aRR for poor functional outcome 1.2 (95% CI 1.0-1.4).

Conclusions: Preventive antibiotics were not associated with reduced risk of DCI or poor outcome in aSAH patients in the ICU.