The patients with intraventricular hemorrhage (IVH) were treated with recombinant tissue plasminogen activator (rt-PA) injected directly into the lateral ventricles, followed by ventricular drainage. All had a decreased level of consciousness before treatment (Glasgow Coma Scale score 10 +/- 3.4). A total dose between 2 and 12 mg of rt-PA (6.4 +/- 3.3) was administered. For eight patients with aneurysmal IVH, treatment with rt-PA began with two patients the same day as the aneurysm clipping, and the day after with six patients. For a patient with an excision of a ruptured arteriovenous malformation and a patient with IVH resulting from a lateral ventricular catheterization during posterior fossa tumor surgery, treatment with rt-PA started 24 hours after surgery. After an injection of rt-PA, the ventricular drain was closed for 1 hour, followed by alternate-hourly drainage and intracranial pressure (ICP) monitoring. Five patients received a second injection of rt-PA on the second postoperative day, and one patient received a third dose on the third day. Among the eight patients given rt-PA the day after surgery, the volume of external cerebrospinal fluid (CSF) drainage for 24 +/- 8 hours before treatment was 61 +/- 57 ml, and the mean ICP was 22 +/- 5 mm Hg during this same time. Younger age and poorer neurological condition correlated with higher ICP before treatment.(ABSTRACT TRUNCATED AT 250 WORDS)