Use of Dexmedetomidine to Reduce Emergence Delirium Incident in Children

Emergence delirium from general anesthesia is a common problem in the pediatric population with a reported incidence of up to 80%. In addition to being jarring to children and their parents, ED can cause significant physical harm, particularly to the surgical site. ED is also associated with accidental removal of surgical dressings and drains, intravenous and intra-arterial catheters, increased nursing care, extended recovery room stays, and delayed reunion with parents. Emergence delirium is especially associated with sevoflurane, the most commonly used inhalation anesthetic in pediatrics. At present, there is no single definition of pediatric ED because of its heterogeneous clinical presentation. It has been described as an acute phenomenon in which the child is irritable, uncompromising, uncooperative, incoherent, and inconsolably crying, moaning, kicking or thrashing. Typically, these children do not recognize or identify familiar objects or people, and often exhibit combative behavior. Although ED is a self-limiting phenomenon, it is especially dangerous in the interventional neuroradiologic patient whose femoral artery has been catheterized and must be kept immobile in the immediate post-operative period. These patients also have multiple intravenous and intra-arterial catheters which can be dislodged during an episode of ED. Numerous pharmacologic agents including benzodiazepines, opioids, ketamine, and clonidine, have been studied as prophylactic agents for ED but have met with varying success. Promising results with the α-2 adrenergic agonist clonidine, have spurred interest in a new α-2 adrenergic agonist, dexmedetomidine.

Dexmedetomidine is highly selective for the 2A subtype of the central presynaptic α-2 adrenergic receptor which is associated with sedation and analgesia. It is currently approved for use in adults as a sedative agent in intensive care units but has been used in myriad other ways for sedation. As a sedative, dexmedetomidine is unusual in that it does not depress respiratory drive because its actions are not mediated by the GABA-mimetic system. The quality of sedation produced by dexmedetomidine is unique, and has been described as "cooperative sedation," in which patients can interact with healthcare providers and follow verbal commands. This particular sedation profile permits a patient to be comfortably sedated, yet cooperate for an accurate neurological exam. The most extreme example of this is the awake craniotomy, in which a patient undergoes a neurological examination during surgery. In addition to being sedative, dexmedetomidine is also analgesic and suppresses shivering, making it especially useful in the perioperative period.

There have been studies suggesting a use for dexmedetomidine in ED yet none have examined its use in the pediatric neurosurgical population. Treatment of ED in pediatric neurosurgical patients involves balancing the need for smooth emergence with the need for accurate neurological exams. Benzodiazepines and opioids are currently used to treat ED but are long-acting, interfere with neurological exams, and carry the risks of respiratory depression, nausea, vomiting, and acute tolerance. Dexmedetomidine provides an alternative to current treatment modalities for ED, which does not interfere with neurological exams.