Objective: Intraventricular nicardipine (IVTN) is a treatment option for severe vasospasm in patients with subarachnoid hemorrhage (SAH). However, its acute effects on cerebral hemodynamics have not been studied in detail.
Methods: Between June 2008 and December 2010, IVTN was administered (mainly 4mg every 8h) to 11 SAH patients (54 doses) with multimodality monitoring for refractory vasospasm. Retrospective analyses on physiological parameters were made from baseline and up to 6h after IVTN injection. Statistical analysis was performed with a mixed-effects model.
Results: Mean intracranial pressure (ICP) increased slightly, reaching its peak at 20min after IVTN injection (2.5±0.9mmHg (mean±standard error), P<0.01), and decreased gradually thereafter over the next hour. Mean cerebral perfusion pressure transiently decreased 20-30min after injection (3.7±1.8mmHg, P<0.05). Mean arterial pressure, partial pressure of brain oxygen tension (PbtO2), cerebral blood flow (CBF), autoregulation indices did not change significantly. Lactate/pyruvate ratio and glucose remained stable. One patient underwent transcranial Doppler ultrasonography monitoring while on IVTN, which showed a transient increase in mean flow velocity with concomitant decrease in Pulsatility index, suggesting vasodilation in the distal resistance vessels.
Conclusions: The vasodilatory effect of IVTN transiently increased ICP, but did not significantly affect PbtO2, CBF or oxidative glucose metabolism in the immediate phase after injection.
Keywords: Autoregulation index; Brain oxygen tension; Cerebral blood flow; Intraventricular nicardipine; Multimodality monitoring; Subarachnoid hemorrhage.
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