Definition Autonomic disturbances are disorders that affect the autonomic neurons of either or both the sympathetic and the parasympathetic nervous systems. Since the autonomic nervous system supplies almost every organ in the body, autonomic diseases influence localized organ function as…
Edema refers to abnormal, excessive accumulation of fluid in the cells, tissues, or body cavities. Brain edema results from excess accumulation of water in the extracellular and/or intracellular compartments of the brain. The brain is protected by a closed, rigid…
Definition Seizure activities are not only difficult to diagnose intraoperative in an anesthetized patient; they are also less recognized clinically, as compared to postoperative seizures in the intensive care unit. Seizure activity may be evident only in cases of incomplete…
Definition Pneumocephalus is defined as an asymptomatic intracranial collection of air, commonly occurring after craniotomy or cranial burr hole. In a retrospective study, the incidence of intracranial air collection varied from 73% in park-bench position, 57% in prone position, and…
Definition Normal perfusion pressure breakthrough (NPPB) can be defined as the occurrence of multifocal areas of hemorrhage associated with unexplained cerebral edema after the resection of high-flow arteriovenous malformations (AVMs). Various theories have been proposed to explain the hemodynamic basis…
Definition Hydrocephalus (derived from Greek words hydros meaning water and cephalus meaning head) is defined as the excessive accumulation of cerebrospinal fluid (CSF) in the ventricular system and cisterns of the brain, leading to an increase in intracranial pressure (ICP)…
Definition Emergence from general anesthesia is defined as the return of neuromuscular conduction, airway protective reflexes, and appropriate level of consciousness following discontinuation of anesthetic agents at the end of the surgery or intervention. Failure to regain the expected level…
Case Synopsis A 73-year-old woman with known severe mitral regurgitation and a permanent pacemaker is admitted to the surgical intensive care unit with urosepsis and refractory hypotension. Because of her lack of hemodynamic response to fluid boluses, a pulmonary artery…
Overview Brain herniation is the displacement of brain tissue through the rigid dural folds (i.e., falx and tentorium) or skull openings (e.g., foramen magnum). Although patients with chronic brain herniation associated with developmental defects, such as Arnold–Chiari malformation, may remain…
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