title: Sub-Tenon's block reduces both intraoperative and postoperative analgesia requirement in vitreo-retinal surgery under general anaesthesia.
abstract: OBJECTIVE
  We compared the effects of sub-Tenon's local anaesthetic block and placebo on peri-operative opioid requirement and cardiovascular stability and on postoperative pain, nausea and vomiting in patients undergoing vitreo-retinal surgery under general anaesthesia.
  
  
  METHODS
  We studied 43 patients undergoing vitreo-retinal surgery under general anaesthesia in a randomized double blind study. Patients received a standard general anaesthetic followed by a sub-Tenon's injection of 4-5 mL of either bupivacaine 0.75% or saline. We recorded intraoperative invasive arterial pressure, then the incidence and severity of pain and of nausea and vomiting, for 24 h postoperatively.
  
  
  RESULTS
  In the sub-Tenon's bupivacaine group, there was a significant reduction in the perioperative opioid use and a reduction in the frequency of bradycardia and hypertensive episodes, defined as a rise > 25% of baseline for a duration of > 3 min. The sub-Tenon's bupivacaine group also had significantly lower pain scores and nausea scores at 12 h, concomitant with a lower consumption of analgesia and antiemetics.
  
  
  CONCLUSIONS
  This local anaesthetic technique is effective in vitreo-retinal surgery and can be safely applied to this population of patients regardless of axial length.
authors.affiliation: Oxford Eye Hospital, Department of Anaesthetics, Oxford, UK. andrew.farmery@nda.ox.ac.uk
authors.forename: A D
authors.initials: AD
authors.lastname: Farmery
authors.forename: D
authors.initials: D
authors.lastname: Shlugman
authors.forename: R
authors.initials: R
authors.lastname: Rahman
authors.forename: P
authors.initials: P
authors.lastname: Rosen
mesh_terms: D000082:Acetaminophen / Q000008:administration & dosage / Q000627:therapeutic use; D000368:Aged; D000700:Analgesics / Q000008:administration & dosage / Q000627:therapeutic use*; D018712:Analgesics, Non-Narcotic / Q000008:administration & dosage / Q000627:therapeutic use; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000627:therapeutic use; D000768:Anesthesia, General; D000772:Anesthesia, Local / Q000379:methods*; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000627:therapeutic use; D001794:Blood Pressure / Q000187:drug effects; D001919:Bradycardia / Q000209:etiology / Q000517:prevention & control; D002045:Bupivacaine / Q000008:administration & dosage / Q000627:therapeutic use; D003061:Codeine / Q000008:administration & dosage / Q000627:therapeutic use; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D006801:Humans; D006973:Hypertension / Q000209:etiology / Q000517:prevention & control; D008875:Middle Aged; D016017:Odds Ratio; D013508:Ophthalmologic Surgical Procedures / Q000009:adverse effects*; D010149:Postoperative Pain / Q000209:etiology / Q000517:prevention & control; D019990:Perioperative Care / Q000706:statistics & numerical data*; D020250:Postoperative Nausea and Vomiting / Q000517:prevention & control
chemical_list: D000700:Analgesics; D018712:Analgesics, Non-Narcotic; D000701:Analgesics, Opioid; D000779:Anesthetics, Local; D000082:Acetaminophen; D003061:Codeine; D002045:Bupivacaine