Multimodal Monitoring in Subarachnoid Hemorrhage

In severely injured patients, the immediate goal of resuscitation is restoration and maintenance of adequate tissue metabolism by ensuring sufficient delivery of fuel, typically oxygen and glucose, to meet cellular metabolic demands. In neurocritical care, traditional goals of resuscitation—intracranial pressure (ICP), cerebral perfusion pressure (CPP), and the clinical examination—have been extrapolated from those of general critical care. These variables are analogous to central venous pressure, mean arterial pressure, and urine output and are similarly crude. These distant surrogates for cerebral perfusion do not account for dynamic changes in cerebral autoregulation, tissue metabolic rate, cellular fuel use, and microcirculatory dysfunction, all of which impact tissue metabolic health. Although standard, it seems intuitively obvious that a uniform approach of maintaining ICP 60 mm Hg is overly simplistic. This approach does not address either significant baseline differences in patient physiology nor the complex, dynamic, and variable pathophysiological changes that ensue after severe brain injury. A more tailored therapeutic strategy that responds to multiple simultaneously measured and more relevant physiological variables is logically appealing. Until recently, however, the requisite individual patient physiology was inaccessible at the bedside.The emergence of technology that allows for continuous real-time bedside monitoring of cerebral physiology marks a new era in neurocritical care. These monitors facilitate assessment of therapeutic efficacy and may provide more relevant physiological end points for resuscitation. Combining these monitors in a multimodal approach allows for the practice of goal-directed cerebral resuscitation that emphasizes the individual patient's unique neurological and systemic physiology.Aneurysmal subarachnoid hemorrhage (SAH) is an example of a disease in which individualized goal-directed cerebral resuscitation using multimodality neuromonitoring might influence therapy and outcome. After initial patient stabilization and aneurysm exclusion from the circulation, care focuses on prevention of secondary neuronal injury. Of those who survive the initial hemorrhage, …