[Prologue. Recommendations-Clinical practice guideline for subarachnoid hemorrhage caused by ruptured intracranial...

To provide evidence-based clinical practice guidelines for managing subarachnoid hemorrhage due to spontaneous rupture of an intracranial aneurysm. The ultimate purpose of the guidelines is to contribute to improving quality of care and reduce unnecessary costs related to the application of futile treatments. Systematic review of the literature indexed in the principal databases. Articles identified were categorized according to levels of evidence (1 to 5) and recommendations that could be derived were classified according to strength (A, B, and C). Some recommendations cannot be based on randomized controlled trials because the utility of certain practices is already clear; no one will investigate them or it would not be ethical to do so. We bore in mind that while many current practices for which no evidence is available may be ineffective, but others may be highly effective even though proof may never be available. Therefore, the guidelines considered that lack of evidence must not be used as the only reason for limiting the use of a diagnostic method or treatment. Nor would lack of evidence be the reason for limiting the use of health care resources.