Merits and pitfalls of multimodality brain monitoring.

In 1841 Magendi pioneered to measure cerebrospinal fluid pressure using the ‘‘sphygmometer,’’ an instrument originally designed for assessment of blood pressure. From then on, it took 110 years before the first intracranial pressure (ICP) monitoring data has been published in 1951, first ever introducing the important key-word of ‘‘monitoring’’ in the context of the human brain [1]. From this moment the field of brain monitoring has been growing continuously. Apart from recording of ICP and cerebral perfusion pressure (CPP), modern multimodality brain monitoring comprises several techniques including assessment of brain tissue oxygenation (PbrO2), brain metabolism, and cerebral blood flow. Noninvasive approaches are transcranial Doppler (TCD) ultrasonography, EEG monitoring, and near-infrared spectroscopy (NIRS). Most of the experience in multimodality brain monitoring has been gained from comatose patients after traumatic brain injury, poor grade subarachnoid hemorrhage, or severe stroke. The main objectives of brain monitoring are (1) the detection of ongoing secondary brain injury following the primary insult, (2) guiding therapeutic interventions, and (3) prediction the outcome. Ideally, brain monitoring should prompt a timely and appropriate intervention and should be included in scheduled management protocols. Modalities and Their Merits