Cutting Edge of Neurocritical Care

Emerging from its roots in the care of complex neurosurgical patients, the field of neurocritical care has developed into a comprehensive approach for patients in whom the brain, spinal cord, or peripheral nerves are acutely injured for the last 30 years. Specialized neurocritical care units, which now exist in a substantial number of tertiary care centers across the country, treat patients with acute injuries, and infections of the brain and spinal cord, severe ischemic and hemorrhagic stroke, and status epilepticus. Specialty training in neurocritical care in programs accredited by the United Council of Neurologic Subspecialties now enables specialists to become board certified. The large majority of board certified neurointensivists are neurologists, with neurosurgeons, anesthesiologists, internists, emergency physicians and pediatricians forming the remainder. Beyond primary disorders of the central and peripheral nervous system, the brain, peripheral nerves, and muscles are frequently affected by systemic critical illness. Thus, intensive care units of all specialties treat patients who can benefit from neurointensive care. The articles assembled in this issue, therefore, address a range of challenges to the care and study of patients in all of the intensive care units, although their focus primarily remains on those patients with central and peripheral nervous system injuries that lead to neuro-intensive care unit admission. Neurocritical care clearly makes a difference in the lives of patients with severe brain injuries [1, 2], but outcomes are often very poor and our patients need much more effective interventions. For the present issue, we have solicited reviews from distinguished neurointensivists that cover a broad range of recent advances in the field and highlight emerging areas of promise. Response to secondary brain injury is quite disparate when comparing pediatric brain injury and adult brain injury. We have devoted the opening article of this issue to pediatric neurocritical care, which is steadily developing into its own subspecialty at the junction of pediatric critical care and pediatric neurology. Adult neurocritical care clearly has much to offer the pediatrician, but this can only be a rough foundation. Pediatric neurocritical care must continue to develop its own body of knowledge, as well as clinical trials, if it is to help our children as fully as possible. Monitoring disease progress in the neurocritical care population is a core challenge. The bedside examination remains the cornerstone of our assessment of neurological function, yet all too often, it is ambiguous or clouded by the effects of medications or comorbid conditions. The use of biomarkers and electrophysiological monitoring to assess and follow dynamic disease states, as well as dynamic changes in brain function is an area of active investigation. The bulk of these reviews focus on emerging therapeutics. Oxidative stress is an important mechanism underlying many of the most common conditions in critical care medicine, as well as neurocritical care, and antioxidant interventions are currently the subject of several clinical trials. Anemia appears to be associated with poor outcome in a range of neurocritical care conditions, but whether its correction with red blood cell transfusion leads to benefit or harm remains largely unknown. Still, transfusion remains common, and there is considerable practice variability. Cerebral edema, a response to virtually all brain injuries, remains one of the most vexing challenges in neurointensive care. The fixed volume of the skull allows no space for swelling, and all medical efforts directed at controlling edema aim at reducing volume of the blood, cerebrospinal fluid, or interstitial fluid without specifically targeting the mechanisms underlying edema generation. Novel agents, now in clinical trials, directly inhibit implicated ion channels and may prove to be far more effective at reducing the formation of brain edema. Therapeutic hypothermia, which has become a mainstay of the approach to patients with brain injury secondary to cardiac arrest, is being explored in a number of settings with promising preliminary results. The use of immunomodulatory therapies for diseases has been evaluated in well-conducted clinical trials for diseases of the peripheral nervous system, but we currently rely more on expert recommendation for the treatment of those disorders of the central nervous system. Neurointensive care originally emerged from the care of neurosurgical patients, and, in particular, patients with acute rupture of the cerebral vessels resulting in either subarachnoid or intracerebral hemorrhage. These 2 diseases, along with traumatic brain injury, remain among the most commonly treated in neurointensive care. Although fewer patients undergo craniotomy, they continue to benefit from enormous progress in medical approaches. Disorders that are rare and more varied in their presentation and clinical course require particular vigilance on the part of neurointensivists. These include acute central nervous system infections, as well as vehicles of neuroterrorism. We conclude with a timely review of delirium, a condition that was once called “acute brain failure” [3], and is a common complication of critical illness of all types. Increasingly considered a substantial contributor to poor clinical outcomes, it has historically been treated with sedatives and anti-psychotics, but the benefits of these and other pharmacological interventions are currently being studied. As data from clinical trials accumulate, the rational combination of pharmacological and nonpharmacological strategies based on expert opinions and the results of small studies remains the state-of-the-art. Until recently, the neuro-intensive care unit has remained a “black box,” with a relative paucity of novel therapeutics and approaches directed at improving the care of acute neurologically injured patients. Significant progress has been made in recent years, and the coming years are likely to see a continued explosion of advances that have a direct impact on patient outcome, both with regard to mechanism of disease and neurotherapeutics.