Continuous Intrathecal Milrinone Administration via IRRA flow Intraventricular Catheter for Refractory Cerebral Vasospasm in Subarachnoid Hemorrhage: A Case Report

Background/Objective The IRRA flow device combines intracerebroventricular (ICV) medication infusion, cerebrospinal fluid (CSF) irrigation, and continuous intracranial pressure (ICP) monitoring. While ICV milrinone is conventionally given as a bolus to manage vasospasm after aneurysmal subarachnoid hemorrhage (aSAH), this case presents the use of continuous ICV milrinone infusion via IRRA flow in a patient with refractory cerebral vasospasm following aSAH. Results A 47-year-old female with aSAH (Hunt Hess 2, Modified Fisher Grade 4) underwent coil embolization for a ruptured left PICA aneurysm. Despite standard management, severe vasospasm was detected in the bilateral middle cerebral arteries and basilar arteries on hospital day 6. Following initiation of systemic milrinone IV and intra-arterial verapamil treatment, subsequent transcranial Doppler (TCD) and CT angiogram revealed persistent vasospasm. Elevated ICPs precluded further angiography or ICV bolus therapy through the existing external ventricular drain (EVD). An IRRA flow catheter was inserted intraventricularly for continuous CSF drainage and ICV milrinone administration (2.6 mg/kg/day). Over days 8 to 12, vasospasm improved significantly, ICP normalized, and neurologic examination permitted extubation. Continuous ICV milrinone therapy was tapered over 5 days, and the IRRA flow system removed on day 14 without complications, leading to discharge for acute rehabilitation. Patient consent for case publication was documented per institutional protocol. Conclusions Continuous intrathecal milrinone infusion via IRRA flow may be a feasible adjunct for treating refractory vasospasm after aSAH. After the combined use of ICV milrinone via the IRRA flow catheter with standard-of-care therapies for severe vasospasm, the patient demonstrated favorable clinical and radiographic improvement without complications.