title: Subanesthetic ketamine infusions for the treatment of children and adolescents with chronic pain: a longitudinal study.
abstract: BACKGROUND
  Chronic pain is common in children and adolescents and is often associated with severe functional disability and mood disorders. The pharmacological treatment of chronic pain in children and adolescents can be challenging, ineffective, and is mostly based on expert opinions and consensus. Ketamine, an N-methyl-D-aspartate receptor antagonist, has been used as an adjuvant for treatment of adult chronic pain and has been shown, in some instances, to improve pain and decrease opioid-requirement. We examined the effects of subanesthetic ketamine infusions on pain intensity and opioid use in children and adolescents with chronic pain syndromes treated in an outpatient setting.
  
  
  METHODS
  Longitudinal cohort study of consecutive pediatric patients treated with subanesthetic ketamine infusions in a tertiary outpatient center. Outcome measurements included self-reported pain scores (numeric rating scale) and morphine-equivalent intake.
  
  
  RESULTS
  Over a 15-month period, 63 children and adolescents (median age 15, interquartile range 12-17 years) with chronic pain received 277 ketamine infusions. Intravenous administration of subanesthetic doses of ketamine to children and adolescents on an outpatient basis was safe and not associated with psychotropic effects or hemodynamic perturbations. Overall, ketamine significantly reduced pain intensity (p < 0.001) and yielded greater pain reduction in patients with complex regional pain syndrome (CRPS) than in patients with other chronic pain syndromes (p = 0.029). Ketamine-associated reductions in pain scores were the largest in postural orthostatic tachycardia syndrome (POTS) and trauma patients and the smallest in patients with chronic headache (p = 0.007). In 37% of infusions, patients had a greater than 20 % reduction in pain score. Conversely, ketamine infusions did not change overall morphine-equivalent intake (p = 0.3).
  
  
  CONCLUSIONS
  These data suggest that subanesthetic ketamine infusion is feasible in an outpatient setting and may benefit children and adolescents with chronic pain. Further, patients with CRPS, POTS, and a history of trauma-related chronic pain are more likely to benefit from this therapeutic modality.
authors.affiliation: Divisions of Anesthesiology and Pain Medicine, The Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's Research Institute, Children's National Health System, George Washington University School of Medicine and Health Sciences, Washington, USA. KathyAnn.Sheehy@vcuhealth.org.
authors.forename: Kathy A
authors.initials: KA
authors.lastname: Sheehy
authors.affiliation: Divisions of Anesthesiology and Pain Medicine, The Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's Research Institute, Children's National Health System, George Washington University School of Medicine and Health Sciences, Washington, USA. emuller1@tulane.edu.
authors.forename: Elena A
authors.initials: EA
authors.lastname: Muller
authors.affiliation: Divisions of Anesthesiology and Pain Medicine, The Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's Research Institute, Children's National Health System, George Washington University School of Medicine and Health Sciences, Washington, USA. clippold@nursing.upenn.edu.
authors.forename: Caroline
authors.initials: C
authors.lastname: Lippold
authors.affiliation: Center for Sickle Cell Disease, Department of Internal Medicine, Howard University, Washington, USA. snouraie@howard.edu.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Nouraie
authors.affiliation: Divisions of Anesthesiology and Pain Medicine, The Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's Research Institute, Children's National Health System, George Washington University School of Medicine and Health Sciences, Washington, USA. JFINKEL@childrensnational.org.
authors.forename: Julia C
authors.initials: JC
authors.lastname: Finkel
authors.affiliation: Divisions of Anesthesiology and Pain Medicine, The Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's Research Institute, Children's National Health System, George Washington University School of Medicine and Health Sciences, Washington, USA. zquezado@childrensnational.org.|Center for Neuroscience Research, Children's Research Institute, Children's National Health System, Washington, USA. zquezado@childrensnational.org.
authors.forename: Zenaide M N
authors.initials: ZM
authors.lastname: Quezado
mesh_terms: D000293:Adolescent; D000553:Ambulatory Care / Q000379:methods*; D000771:Anesthesia, Intravenous / Q000379:methods*; D000778:Anesthetics, Dissociative / Q000008:administration & dosage; D002648:Child; D059350:Chronic Pain / Q000175:diagnosis / Q000628:therapy*; D005240:Feasibility Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007262:Infusions, Intravenous; D007649:Ketamine / Q000008:administration & dosage*; D008297:Male; D010147:Pain Measurement; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D000778:Anesthetics, Dissociative; D007649:Ketamine