Background Subarachnoid hemorrhage (SAH) results from extravasation of blood into the subarachnoid space and is associated with high morbidity and mortality. This study aimed to compare systolic blood pressure variability (SBPV) and intracranial pressure variability (ICPV) in three 8-hour intervals during the first 24 hours after hospital admission and investigate their associations with discharge disposition and in-hospital mortality.

Methods We retrospectively reviewed charts of adult patients with spontaneous, non-traumatic SAH admitted for at least 24 hours from 2016-2020. Hourly measurements were recorded for both systolic blood pressure (SBP) and intracranial pressure (ICP), and SBPV and ICPV were measured using successive variation (SV) and standard deviation (SD).

Results A total of 240 patients were included (mean age 57±14.2 years, 64.6% female); 40 (16.7%) died. In the first 8-hour interval, higher SBP-SV (22.7±13.8) was significantly associated with mortality (p=0.028) and not being discharged home (p=0.022), compared to those who survived (17.6±7.5) or were discharged home (16.7±5.5). No significant differences in ICPV emerged for mortality or disposition, though higher ICP-SV in the first 8 hours approached significance (p=0.054) for discharge disposition. Receiver operating curve analysis showed poor discrimination for the first 8-hour SBP-SV (area under the curve 0.62) and failure for ICP-SV (0.51) in predicting mortality.

Conclusions Greater SBP variability in the first 8 hours was linked to poorer outcomes, underscoring the potential importance of stabilizing blood pressure in this critical window. No clear association was observed between ICP variability and outcomes.

The authors have declared no competing interest.

This study did not receive any funding

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

This study was approved by the University of Maryland Baltimore IRB (HP-00084554)

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Jane.Quackenbushsom.umaryland.edu

jolexasom.umaryland.edu

kimay00gmail.com

ylin1216terpmail.umd.edu

drscard013gmail.com

qtransom.umaryland.edu

# Co-Senior Authors

↵Conflict of Interest: There were no conflicts of interest while creating this manuscript. The authors received no funding from any external or internal sources for the work of this manuscript.

All data produced in the present study are available upon reasonable request to the authors