title: An effective dose of ketamine for eliminating pain during injection of propofol: a dose response study.
abstract: OBJECTIVE
  Ketamine can completely eliminate pain associated with propofol injection. However, the effective dose of ketamine to eliminate propofol injection pain has not been determined. The purpose of this study was to determine the effective dose of ketamine needed to eliminate pain in 50% and 95% of patients (ED50 and ED95, respectively) during propofol injections.
  
  
  METHODS
  This study was conducted in a double-blinded fashion and included 50 patients scheduled for elective gynecological laparoscopy under general anesthesia. The initial dose of ketamine used in the first patient was 0.25mg/kg. The dosing modifications were in increments or decrements of 0.025 mg/kg. Ketamine was administered 15 seconds before injecting propofol (2.5mg/kg), which was injected at a rate of 1mL/s. Patients were asked to rate their pain during propofol injection every 5s econds using a 0-3 pain scale. The highest pain score was recorded. The ED50, ED95 and 95% confidence intervals (CI) were determined by probit analyses.
  
  
  RESULTS
  The dose of ketamine ranged from 0.175 to 0.275 mg/kg. The ED50 and ED95 of ketamine for eliminating pain during propofol injection were 0.227 mg/kg and 0.283 mg/kg, respectively (95%CI: 0.211-0.243 mg/kg and 0.26-0.364 mg/kg, respectively).
  
  
  CONCLUSIONS
  Ketamine at an approximate dose of 0.3mg/kg was effective in eliminating pain during propofol injection.
authors: Department of anesthesiology, Wuxi maternity and child health hospital affiliated Nanjing medical university, 48, Huaishu-Xiang, 214002 Wuxi, Jiangsu, China. Electronic address: wxfy2071@163.com.
authors: M
authors: M
authors: Wang
authors: Q
authors: Q
authors: Wang
authors: Y Y
authors: YY
authors: Yu
authors: W S
authors: WS
authors: Wang
mesh_terms: D000328:Adult; D000778:Anesthetics, Dissociative / Q000008:administration & dosage* / Q000627:therapeutic use*; D018686:Anesthetics, Intravenous / Q000009:adverse effects*; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D013509:Gynecologic Surgical Procedures; D006801:Humans; D007275:Injections, Intravenous; D007649:Ketamine / Q000008:administration & dosage* / Q000627:therapeutic use*; D016015:Logistic Models; D008875:Middle Aged; D010146:Pain / Q000139:chemically induced* / Q000517:prevention & control*; D010147:Pain Measurement / Q000187:drug effects; D015742:Propofol / Q000009:adverse effects*; D055815:Young Adult
chemical_list: D000778:Anesthetics, Dissociative; D018686:Anesthetics, Intravenous; D007649:Ketamine; D015742:Propofol
keywords: Douleur; Ketamine; Kétamine; Pain on injection; Propofol