title: Ketamine in outpatient arthroscopic shoulder surgery: Effects on postoperative pain, hemodynamic stability and process times.
abstract: BACKGROUND
  Pain after arthroscopic shoulder surgery is often severe, and establishing a pain treatment regimen that does not delay discharge can be challenging. The reported ability of ketamine to prevent opioid-induced hyperalgesia has not been investigated in this particular setting.
  
  
  METHODS
  300 adult patients scheduled for shoulder arthroscopy under general anesthesia were recruited for this observational clinical trial and were allotted to either receive 1mg/kg IV bolus of ketamine before surgery (ketamine group, KG) or to a control group (CG) without ketamine. NRS pain scores were obtained on the operative day and on postoperative days 1 and 2 and compared between groups. Secondary variables were blood pressure, heart rate, process times, satisfaction with the anesthetic and unwanted effects.
  
  
  RESULTS
  Pain severity did not differ significantly between the groups at any time. Propofol injection rate and cumulative dose were higher in the KG. Heart rates and blood pressures were similar. Time to emergence and time in PACU were longer and vomiting was more frequent in patients given ketamine.
  
  
  CONCLUSIONS
  Preoperative low-dose ketamine added to a general anesthetic does not reduce perioperative pain after outpatient shoulder arthroscopy. It increases procedural times and the incidence of PONV.
authors.affiliation: Department of Anaesthesiology, Emergency and Intensive Care Medicine, University of Göttingen Medical School, Göttingen, Germany.
authors.forename: Hanna
authors.initials: H
authors.lastname: Schotola
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany.
authors.forename: Karl-Christian
authors.initials: KC
authors.lastname: Kirsch
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Höcker
authors.affiliation: Department of Anaesthesiology, Emergency and Intensive Care Medicine, University of Göttingen Medical School, Göttingen, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Egan
authors.affiliation: Department of Anaesthesiology, Emergency and Intensive Care Medicine, University of Göttingen Medical School, Göttingen, Germany.
authors.forename: Benedikt
authors.initials: B
authors.lastname: Büttner
authors.affiliation: Clinic for Anesthesiology, University Hospital Regensburg, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Wiese
authors.affiliation: Department of Anaesthesiology, Emergency and Intensive Care Medicine, University of Göttingen Medical School, Göttingen, Germany.
authors.forename: Ashham
authors.initials: A
authors.lastname: Mansur
authors.affiliation: Department of Anaesthesiology, Emergency and Intensive Care Medicine, University of Göttingen Medical School, Göttingen, Germany.
authors.forename: José Maria
authors.initials: JM
authors.lastname: Hinz
authors.affiliation: Center for Anesthesiology, Emergency and Intensive Care Medicine, University Hospital Göttingen, Robert-Koch Str. 40, 37075 Göttingen, Germany, Tel.: +49 551 396051.
authors.forename: Ingo
authors.initials: I
authors.lastname: Bergmann
keywords: Ketamine; day surgery; general anaesthesia; outpatient; postoperative pain