Subarachnoid hemorrhage

This chapter focuses on neurological clinical trials related to subarachnoid hemorrhage (SAH) and the epidemiology, etiology, and diagnosis of SAH. The management of SAH and vasospasm remains challenging, with few proven interventions that alter clinical outcomes. Currently, the only regularly used intervention in North America with some evidence from clinical trials supporting their efficacy include early definitive therapy, seizure prophylaxis, electrolyte normalization, intracerebral pressure monitoring and correction, nimodipine, triple H therapy composed of hypertension, hypervolemia, and hemodilution (HHH therapy), balloon angioplasty, and intra-arterial papaverine therapy. Although numerous clinical trials have been conducted in search of interventions that may alter outcomes, most have shown a little, no, or inconsistent benefits of proposed interventions, compared with placebo. The failure of these clinical trials is multifactorial, related to the underlying complexity of the mechanisms resulting in vasospasm, the failure of clinical trials to recruit enough participants to provide adequate power to assess the efficacy of interventions, and the lack of appropriate, sensitive, and specific measures of clinical endpoints. Even so, the morbidity and mortality of vasospasm are theoretically preventable. Therefore, it is critical that clinical trials continue to investigate means of preventing early rebleeding, maintaining perfusion, and preventing vascular constriction and subsequent neurological deterioration.