Time from onset of SIRS to antibiotic administration and outcomes after subarachnoid hemorrhage

The interval from presentation with systemic inflammatory response syndrome (SIRS) to the start of antibiotic administration affects mortality in patients with sepsis. However, patients with subarachnoid hemorrhage (SAH) often develop SIRS directly from their brain injury, making it a less useful indicator of infection. We therefore hypothesized that SIRS would not be a suitable trigger for antibiotics in this population.

We examined the time from the development of SIRS until antibiotic initiation and its relationship to long-term neurological outcomes in patients with nontraumatic SAH. Patients' baseline characteristics, time of antibiotic administration, and hospital course were collected from retrospective chart review. The primary outcome, 6-month functional status, was prospectively determined using blinded, structured interviews incorporating the modified Rankin Scale (mRS).

Sixty-six of 70 patients with SAH during the study period had 6-month follow-up and were included in this analysis. SIRS developed in 57 patients (86%, 95% CI 78-95%). In ordinal logistic regression models controlling for age and illness severity, the time from SIRS onset until antibiotic initiation was not associated with 6-month mRS scores (OR per hour, 0.994; 95% CI 0.987-1.001).

In this cohort of patients with SAH, time from SIRS onset until antibiotic administration was not related to functional outcomes. Our results indicate that SIRS is nonspecific in patients with SAH, and support the safety of withholding antibiotics in those who lack additional evidence of infection or hemodynamic deterioration.