The release of EAAs is closely linked to the release of structural amino acids and may thus reflect nonspecific development of membrane micropores, rather than presynaptic neuronal vesicular exocytosis. The magnitude of EAA release in patients with focal contusions and ischemic events may be sufficient to exacerbate neuronal damage, and these patients may be the best candidates for treatment with glutamate antagonists in the future.

The investigators undertook a retrospective analysis of ventriculostomy infections to evaluate their relationship to monitoring duration and prophylactic catheter exchange. In 1984, the results of an epidemiological study of ventriculostomy-related infection were published. One of the conclusions of the paper was that the incidence of ventriculostomy-related infections rose after 5 days of monitoring. This led to the recommendation that catheters be prophylactically changed at 5-day intervals if prolonged monitoring was required. A recent randomized prospective study on central venous catheters showed no reduction in infection with prophylactic catheter exchanges. This has led the authors to reexamine their experience with ventriculostomy infections. Data on 584 severely head injured patients with ventriculostomies were prospectively collected in two data banks, The Traumatic Coma Data Bank and The Medical College of Virginia Neurocore Data Bank. These data were retrospectively analyzed for factors associated with ventriculostomy related infections. It was found that there is a relationship of ventriculitis to monitoring duration but it is not simple or linear. There is a rising risk of infection over the first 10 days, but infection then becomes very unlikely despite a population that continues to be at risk. Patients in whom catheters were replaced prior to 5 days did not have a lower infection rate than those whose catheters were exchanged at more than 5-day intervals. Based on these data, it is recommended that ventriculostomy catheters for intracranial pressure monitoring be removed as quickly as possible, and in circumstances in which prolonged monitoring is required, there appears to be no benefit from catheter exchange.

Acutely increased intra-abdominal pressure causes a significant increase in intracranial pressure and a decrease in cerebral perfusion pressure. Increased intra-abdominal pressure appears to produce this effect by augmenting pleural and other intrathoracic pressures and causing a functional obstruction to cerebral venous outflow via the jugular venous system. It is possible that the same phenomenon may be why persons with chronically increased intra-abdominal pressure, such as the morbidly obese, suffer from a high frequency rate of idiopathic intracranial hypertension.

Background and Purpose Patients with intracerebral hemorrhage (ICH) and intraventricular hemorrhage (IVH) have a reported mortality of 50–80%. We evaluated a clot lytic treatment strategy for these patients in terms of mortality, ventricular infection, and bleeding safety events and for its effect on the rate of intraventricular clot lysis. Methods 48 Patients were enrolled at 14 centers and randomized to treatment with 3mg recombinant tissue plasminogen activator (rt-PA) or placebo. Demographic characteristics, severity factors, safety outcomes (mortality, infection, bleeding), and clot resolution rates were compared in the two groups. Results Severity factors, including admission GCS, ICH volume, IVH volume and blood pressure, were evenly distributed, as were adverse events except for an increased frequency of respiratory system events in the placebo-treated group. Neither ICP nor Cerebral Perfusion pressure (CPP) differed substantially between treatment groups on presentation, with EVD closure, or during the active treatment phase. Frequency of death and ventriculitis was substantially lower than expected and bleeding events remained below the pre-specified threshold: mortality (18%, rt-PA; 23%, placebo); ventriculitis (8%, rt-PA; 9%, placebo); symptomatic bleeding (23%, rt-PA; 5% placebo, which approached statistical significance (p=0.1)). The median duration of dosing was 7.5 days for rt-PA and 12 days for placebo. There was a significant beneficial effect of rt-PA on rate of clot resolution Conclusions Low-dose rt-PA for the treatment of ICH with IVH has an acceptable safety profile compared to placebo and prior historical controls. Data from a well-designed Phase III clinical trial, such as CLEAR III, will be needed to fully evaluate this treatment. Clinical Trial Registration Information Participant enrollment began prior to July 1, 2005.