Preoperative anxiety and emergence delirium in children continue to be common even with midazolam premedication. Midazolam is unpleasant tasting even with a flavored vehicle and as a result, patient acceptance is sometimes poor. As an alternative, we evaluated dexmedetomidine administered intranasally. Dexmedetomidine an alpha-2 adrenergic agonist is tasteless, odorless, and painless when administered by this route. Alpha-2 adrenergic agonists produce sedation, facilitate parental separation, and improve conditions for induction of general anesthesia, while preserving airway reflexes. Institutional review board approval was obtained to study 100 pediatric patients randomized to intranasal dexmedetomidine (2 microg/kg) or oral midazolam (0.5 mg/kg) administered 30 to 45 minutes before the surgery. Subjects received general anesthesia with oxygen, nitrous oxide, isoflurane, and analgesics (0.05-0.1 mg/kg morphine or 0.1 mg/kg methadone). Nurses and anesthetists were blinded to the drug administered and evaluated patients for preoperative sedation, conditions for induction of general anesthesia, emergence from anesthesia, and postoperative pain. Responses of 100 patients (50 dexmedetomidine and 50 midazolam) were analyzed. Dexmedetomidine (P=.003) was more effective than midazolam at inducing sleep preoperatively. Dexmedetomidine and midazolam were comparable for conditions at induction (P>0.05), emergence from anesthesia (P>0.05), or postoperative pain (P>0.05). Both drugs were equieffective in these regards. In pediatric patients, dexmedetomidine 2 microg/kg administered intranasally and midazolam 0.5 mg/kg administered orally produced similar conditions during induction and emergence of anesthesia. Intranasal administration of dexmedetomidine is more effective at inducing sleep and in some circumstances offers a useful alternative to oral midazolam in children.

Postoperative ileus (POI), a transient cessation of coordinated bowel function after surgery, is an important health care problem. The etiology of POI is multifactorial and related to both the surgical and anesthetic pathways chosen. Opioids used to manage surgical pain can exacerbate POI, delaying gastrointestinal (GI) recovery. Peripherally acting mu-opioid receptor (PAM-OR) antagonists are designed to mitigate the deleterious effects of opioids on GI motility. This new class is investigational for POI management with the goal of accelerating the recovery of upper and lower GI tract function after bowel resection. In this review, we summarize the mechanisms by which POI occurs and the role of opioids and opioid receptors in the enteric nervous system, discuss the mechanism of action of PAM-OR antagonists, and review clinical pharmacology and Phase II/III POI trial results of methylnaltrexone and alvimopan. Finally, the role of anesthesiologists in managing POI in the context of a multimodal approach is discussed.

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