Intracranial haemorrhage induced at arterial pressure in the rat. Part 1: Description of technique, ICP changes and neuropathological findings.

Intracranial haemorrhage was produced in the caudate nucleus or the lateral ventricle of Sprague Dawley Rats by connecting a stereotactically inserted cannula to the femoral artery. Two types of lesion resulted from this type of arterial-pressure haemorrhage: Contained intracerebral haemorrhage (ICH) and Uncontained haemorrhage. When the haemorrhage was uncontained, a large and transient rise in intracranial pressure (ICP) (to 65mmHg mean) was accompanied by a fall in cerebral perfusion pressure. By contrast, with contained intracerebral haemorrhage, the rise in ICP was smaller (to 18mmHg mean) and neuropathological evidence of ischaemic brain damage was found in areas surrounding the clot. This observation suggests that with ICH there may be a local reduction in flow in tissue immediately surrounding the haematoma.