J.J.Chang, R.A.Armonda, M.Bodo
MedStar Washington Hospital Center, District of Columbia, United States
Keywords: cerebral blood flow, autoregulation, triage, neurocognitive function, traumatic brain injury
Cerebral blood flow autoregulation (CBF-AR) is impaired after severe brain injury. Rapid, front-line therapeutic intervention to optimize CBF-AR is essential to mitigate secondary brain injury and improve clinical outcome. In austere, prehospital settings, resuscitation in polytrauma focuses on hemorrhage control and shock. However, this conventional method of resuscitation is based on a minimal amount of perfusion to support cardiac function and can often leave patients with significant residual neurocognitive dysfunction. Traditional CBF-AR monitoring is conducted in specialized neurocritical care units that utilize invasive intracranial pressure (ICP) monitoring. Non-invasive, facile, portable forms of CBF-AR need to be deployed in austere, prehospital settings in order to diagnose impairment and initiate alternative triage plans that optimize CBF-AR and promote neurological improvement. Rheoencephalography (REG) is a form of non-invasive monitoring based on bioimpedance measurement. In vivo, animal and human studies have established correlations between REG and other modalities, such as laser Doppler flow, near-infrared spectroscopy, and ICP, as well as invasive and noninvasive CBF-AR indices. Studies documented that REG may reflect cerebral volume change, cerebrovascular reactivity, ICP, CBF-AR, and transient brain vasospasm. The potential of REG monitoring in civilian and military applications is tremendous and the practical utilization is promising.