The specialized care of neurosurgical and neurological patients, which was virtually nonexistent as a specialty 20 years ago, has evolved to become one of the most popular components of neurology today. To appreciate the nature of this field and establish where it may be headed requires a description of the clinical practice and its constituent areas of medical knowledge, and a digression into the origins of neurological intensive care units (neuro-ICUs) as well as the medical-political and economic forces that have shaped them. In addition to previous versions of this book, a substantial number of texts, monographs, and review articles (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12) have been devoted to the field (13, 14, 15, 16, 17, 18 and 19), and most comprehensive textbooks of critical care include a chapter or more on neurological aspects. As important, the techniques of caring for critically ill neurological patients have been integrated into the mainstream of many neurology and neurosurgery training programs. In addition to the evolution of the field through courses, textbooks, and interest sections in various professional organizations, the notable inception in 2003 of the Neuro Critical Care Society and a corresponding journal has put the specialty on an equal footing with a number of other derivative fields in neurology and neurosurgery.

Neurologists, neurosurgeons, intensivists, and anesthesiologists have all influenced what has come to be known as neurological intensive care or neurological-neurosurgical critical care; “neuro-ICUs” or their equivalent have become commonplace in hospitals of all sizes. Initially, the development of neurological intensive care was driven by a need to house patients with neurological diseases in one area, and the desire to apply general ICU principles to their care. For the latter reason, many clinical practices have been adopted directly from the experiences in cardiopulmonary and postoperative intensive care, with special emphasis on those problems that are encountered in neurological diseases; for example, the mechanical respiratory failure that characterizes neuromuscular disease, autonomic changes that follow carotid endarterectomy, and nutritional requirements of patients with head injury.

However, the field of neurological and neurosurgical intensive care is mostly defined by a group of problems that derive from the acute aspects of diseases such as stroke, cerebral hemorrhage, brain and spinal cord injury, status epilepticus, encephalitis, generalized neuromuscular paralysis, brain tumors, and postoperative neurosurgical issues that are not addressed easily in a general ICU setting (Table 1.1). The care of these patients relates not only to understanding the neurological examination and knowledge of the course of these diseases, but also to certain physiologic changes in cerebral blood flow, intracranial
pressure, brain and neuromuscular electrical activity, electroencephalography and related techniques, ventilator mechanics, and so on, that have become the province of neurological intensive care. Despite this explicit description, defining the core knowledge of the field has proved somewhat difficult because of the diversity of clinical practices involved. From one limited perspective, it can be stated that the knowledge that underpins neurological intensive care is mainly a compilation of the acute aspects of most neurological illnesses, including those already mentioned. A broader perspective on the field would include a knowledge of all illnesses that risk brain loss or spinal cord function in which intervention might improve outcome, and those neurological illnesses that require intensive medical care and surveillance because of cerebral, respiratory, or cardiovascular dysfunction.

It is also accurate to say that all of the constituent specialties that have contributed to the field—neurology, neurosurgery, critical care, and anesthesiology—have in turn been greatly altered by developments in neurological critical care. The neurological aspects of diseases in those fields have been delineated by critical care neurologists and neurosurgeons; and issues relating to neurological outcome and brain death have been greatly refined through experience in neuro-ICUs. One manifestation of this cross-fertilization has been the identification of several ubiquitous but previously unrecognized neurological manifestations of critical illness that are discussed in Chapter 11.

The rationale for the existence of neuro-ICUs is that a reduction in morbidity and mortality are anticipated from collecting acutely ill neurological patients in a geographic area of a hospital under the care of specially trained nurses and physician staff. In keeping with the model of other ICUs, it might be further anticipated that certain patients with neurological conditions will acquire delayed problems that can only be detected
by close clinical observation and physiological monitoring and that these problems will benefit from special and rapid interventions, all of which are beyond the usual capabilities of a hospital ward. To the extent that the medical needs of such patients have reached a state of such complex and specialized nature that there is a requirement for specially trained individuals and unique types of technologic monitoring, the utility of a neuro-ICU no longer requires defending as it had in the past; only the details of various organizational models and health economics of these units are worth discussing.