cerebral edema and blood pressure, pulse
In cerebral oedema the observations (blood pressure, pulse, respiratory rate etc.) can be all over the place. They can depend on the cause e.g. infectious more likely to have raised pulse (tachycardia) with lower blood pressure (shock) but with the anxiety there might be raised blood pressure. Then with the vomiting, a symptom of cerebral oedema, this could lead to dehydration which leads to lower blood pressure or movement of fluid from the blood to the brain because it is oedematous could also drop the blood pressure. With the cerebral oedema affecting different structures, particularly the brain stem in coning (brain swells, pushes brain out through the big hole at the bottom where all the nerves come out particularly affecting respiratory rate) the respiratory rate could be low. It could also be high due to structures getting less oxygen causing the body to push the sympathetic nervous system to increase heart rate and respiratory rate. 

In conclusion, things can be completely over the place but usually blood pressure is low and there's reflex tachycardia for the reasons explained above. For these reasons, to diagnose cerebral oedema we usually use the characteristic symptoms of nausea, vomiting, faintness and other features in a patient we know is at risk because of the signs and symptoms of the original disease or cause of the cerebral oedema e.g. the cancer, trauma or infection.