What contributed to her subarachnoid hemorrhage in the first place? Is it a condition that might recur? Did she have a berry aneurism or AVM? You might find something behind the the condition that brought her in that might be a collaborative problem. Does she smoke? Does she have high blood pressure? Does she have clotting problems? If you use Wilkinson for your nursing diagnoses, there is a section in the back that lists potential complications/collaborative problems for a lot of conditions. For craniotomy she lists around 18. Seizures, as daytonite mentioned. Cranial nerve impairment (what damage may have been done?) Meningitis from irritation/infection.
Hope any of that helps