Dexmedetomidine to Treat Bariatric Surgery-associated Pain

Overview

Obesity represents one of the most important public health issues according to the World Health Organization and it has reached epidemic proportions globally. The prevalence of childhood obesity has rapidly increased over the past decade and is associated with multiple co-morbid disease states . It is estimated that approximately 15.5% of children and adolescents are obese with a body mass index of ≥95th percentile for age . This not only poses health concerns for the patient, but also places increased demands on our healthcare system that is already overwhelmed by burgeoning costs. Moreover, obese children and adolescents who maintain excessive weight as adults are predisposed to cardiovascular disease and premature death. In carefully selected patients who have failed to lose weight by diet and exercise, bariatric surgery provides an option to obtaining a healthy weight. It is increasingly becoming an attractive option, with the number of adolescents undergoing bariatric surgery in the United States tripling between 2000 and 2003. Obese patients are often afflicted with multi-organ dysfunction and obstructive sleep apnea, which presents unique challenges to the anesthesiologist managing their perioperative care . Bariatric surgery in obese adolescents may be associated with significant postoperative pain. Potent intravenous opioids such as fentanyl and morphine are at the mainstay of perioperative pain management. Unfortunately, respiratory depression and airway obstruction can often occur following administration of opioids in obese patients . This makes providing a safe analgesic regimen difficult during the perioperative setting. As opioids can be associated with respiratory depression and upper airway obstruction, surgeons and anesthesiologists alike must reconcile the adequacy of pain control with the risk of respiratory complications after surgery in obese adolescents.

Dexmedetomidine is a non-opioid drug that has shown some utility during bariatric surgery in the adult population because of its analgesic properties. It is a lipophilic imidazole derivative that is a selective α2-adrenoreceptor agonist with sedative and analgesic properties devoid of respiratory depressant effects . Dexmedetomidine produces sedation by modulating the release of the neurotransmitter norepinephrine within the locus coeruleus of the brain, which is vital to producing an awake state. In addition, by directly stimulating α2-receptors in the spinal cord, dexmedetomidine inhibits the firing of nociceptive neurons responsible for the propagation of pain signals. Although dexmedetomidine is an agent with many off-label clinical applications in the pediatric setting, much about its pharmacokinetic and pharmacodynamics properties remain unknown. This is even more evident for pediatric patients that are obese. Currently, there are no reported pharmacokinetic and pharmacodynamic studies that have investigated dexmedetomidine in obese children and adolescents. Our previous experience with the use of dexmedetomidine in the perioperative period along with our robust obese surgical population certainly supports the notion that we are well poised to conduct the proposed trial