Assessing Effects of Intrathecal Nicardipine on Cerebral Autoregulation and Cortical Activity in Aneurysmal Subarachnoid Hemorrhage
Sithmi Jayasundara1, Jennifer Kim1, Rachel Choi1, Amedeo Rapuano1, Erin Barnes1, Melvin Parasram1, Michele Moura1, Puneet Uppal1, Yilun Chen1, Ilayda Top1, Madelynne Olexa1, Rafael Maarek1, Jennifer Yan1, Rachel Beekman1, Jessica Magid-Bernstein1, Ryan Hebert1, Farhad Bahrassa1, Charles Matouk1, Kevin Sheth1, Emily Gilmore1, Nils Petersen1
1Yale University School of Medicine
Objective:
Characterize the effects of intrathecal nicardipine (ITN) on cerebrovascular function as measured by cerebral autoregulation and cortical activity on quantitative electroencephalography (qEEG) in aneurysmal subarachnoid hemorrhage (aSAH).
Background:
aSAH is a life-threatening condition after which patients are at risk for vasospasm and delayed cerebral ischemia. ITN is an emerging bedside treatment in critically ill aSAH patients with vasospasm. ITN’s impact on cerebral physiology, including the interactions between autoregulation and qEEG changes, are not well understood.
Design/Methods:
We retrospectively evaluated near-infrared spectroscopy (NIRS), mean arterial pressure (MAP), and qEEG continuously collected in aSAH patients undergoing ITN administration. Autoregulatory function was measured by interrogating changes in NIRS-derived tissue oxygenation in response to changes in MAP. Cortical activity was measured by computing percent changes in each qEEG frequency band after artifact reduction and feature extraction. Analyses were restricted to 2 hours pre and 5 hours post ITN to minimize potential for interference given dosing schedules.
Results:
We calculated upper and lower limits of autoregulation (ULA, LLA) and percent changes in qEEG for 68 ITN administrations across 14 patients (median age 59 ± 11 years, Hunt Hess 3.0 ± 0.9, modified Fisher 4.0 ± 0.5). After ITN, patients spent 8.08% less time above ULA (p = 0.04) and 5.28% more time below LLA (p = 0.003). 69.1% (n = 47) of ITN administrations showed a subsequent change in absolute power in the delta band ≥5%. Similar patterns were found in alpha power (n = 43, 63.2%), total power (n = 44, 64.7%), and alpha/delta ratio (n = 36, 52.9%).
Conclusions:
ITN administration was associated with shifts in the autoregulatory curve and changes in cortical activity as measured by qEEG. Autoregulatory shifts were not associated with a consistent EEG signature, which suggests other factors may play a significant role. Further exploratory analyses are on-going.