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Curious Haemodynamics

The Cardiovascular System in Aneurysmal Subarachnoid Haemorrhage
Early Days

Those who have ever treated a patient following a subarachnoid haemorrhage due to a ruptured aneurysm will probably be familiar with some of the concepts I'm going to discuss. As what happens is seemingly out of context, basic errors are often made. However, if you think about what is happening from a (patho)physiological point of view, the management is often easier than it first seems.

To understand the instability that is often seen in patients in the first few hours after the aneurysm ruptures in aSAH, you just have to picture what is happening in the body.

First, the release of arterial blood into the brain causes a swift rise in intracranial pressure. Hence the severe headache at best, loss of consciousness, seizures or brain stem herniation in increasing seriousness. 

The reflex response of the cardiovascular system was well described by Cushing. Hypertension and bradycardia. This is mediated by a huge sympathetic storm that puts enormous strain on the cardiovascular system.