Down syndrome and the autonomic nervous system, an educational review for the anesthesiologist.

Approximately one in every 700 babies in the United States is born with Down syndrome, or 0.14%. Children with Down syndrome have cognitive impairment and congenital malformations necessitating frequent occurrences of general anesthesia and surgery. The thoughtful perioperative care of children with Down syndrome is relevant and acutely complex for the pediatric anesthesiologist. Behavior, sedation, hypotonia, upper airway obstruction, venous access, and bradycardia are omnipresent concerns apart from the surgical pathology. Down syndrome is also associated with autonomic nervous system dysfunction, a comorbidity that is overlooked in discussions of perioperative care and is described thus far in adults. Autonomic nervous system function or dysfunction may explain the phenotypical features of the perioperative challenges listed above. For this reason, understanding the development and measurement of autonomic nervous system function is important for the pediatric anesthesiologist. Definition and quantification of sympathetic and parasympathetic function will be reviewed.