title: Prevention of propofol-induced pain in children: pretreatment with small doses of ketamine.
abstract: OBJECTIVE
  To evaluate the efficacy of ketamine in preventing propofol injection pain in children.
  
  
  METHODS
  Prospective, randomized, double-blinded, placebo-controlled study.
  
  
  METHODS
  University-affiliated hospital.
  
  
  METHODS
  192 ASA physical status 1 and 2 pediatric patients.
  
  
  METHODS
  Patients were randomly assigned to 4 groups. Group S (control) received normal saline as a placebo; Group K1, Group K3, and Group K5 received 0.1 mg/kg, 0.3 mg/kg, and 0.5 mg/kg of ketamine, respectively. Fifteen seconds after the ketamine injection, patients were injected with propofol at a rate of 12 mL/min until loss-of-eyelash reflex.
  
  
  METHODS
  Pain was evaluated blindly at the time of induction using a 4-point scale: 0 = no pain, 1 = mild pain, 2 = moderate pain, and 3 = severe pain. Adverse effects were recorded. Characteristics of induction of anesthesia, such as dose of propofol and time from propofol injection to loss of consciousness (induction duration), were noted.
  
  
  RESULTS
  39 (84.8%) Group S (control) patients had pain. Pretreatment with ketamine reduced the frequency of pain significantly to 56.5%, 17.0%, and 14.9% in Groups K1, K3, and K5, respectively. Furthermore, the frequency of moderate and severe pain in Group K1 (21.8%), Group K3 (6.4%), and Group K5 (4.3%) was significantly (P < 0.001, respectively) reduced compared with Group S (76.1%). Moreover, the dose of propofol for induction in Group K5 was smaller than in Group S, Group K1, and Group K3 (P < 0.05). One patient in Group K5 had emergence agitation.
  
  
  CONCLUSIONS
  Pretreatment with a small dose of ketamine (0.3 mg/kg) reduced the frequency and intensity of propofol injection pain without severe adverse effects.
authors.affiliation: Department of Anesthesiology, Shengjing Hospital of China Medical University, Shenyang, 110004, China.
authors.forename: Guang-yi
authors.initials: GY
authors.lastname: Zhao
authors.forename: Yao
authors.initials: Y
authors.lastname: Guo
authors.forename: Shu-min
authors.initials: SM
authors.lastname: Bao
authors.forename: Ling-xin
authors.initials: LX
authors.lastname: Meng
authors.forename: Li-hong
authors.initials: LH
authors.lastname: Zhang
mesh_terms: D000700:Analgesics / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use; D018686:Anesthetics, Intravenous / Q000008:administration & dosage / Q000009:adverse effects*; D002648:Child; D002675:Child, Preschool; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D017558:Elective Surgical Procedures; D005260:Female; D006801:Humans; D007275:Injections, Intravenous / Q000009:adverse effects; D007649:Ketamine / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use; D008297:Male; D010146:Pain / Q000139:chemically induced / Q000517:prevention & control*; D010147:Pain Measurement / Q000379:methods; D015742:Propofol / Q000008:administration & dosage / Q000009:adverse effects*; D011446:Prospective Studies; D016896:Treatment Outcome
chemical_list: D000700:Analgesics; D018686:Anesthetics, Intravenous; D007649:Ketamine; D015742:Propofol