title: Comparison of pH-adjusted bupivacaine with a mixture of non-pH-adjusted bupivacaine and lignocaine in primary vitreoretinal surgery.
abstract: OBJECTIVE
  To compare the efficacy of alkalinized bupivacaine with that of a mixture of nonalkalinized bupivacaine and lignocaine for local anesthesia in primary vitreoretinal surgery.
  
  
  METHODS
  Through a prospective, double-blind, randomized, controlled clinical trial, 540 consecutive patients undergoing primary vitreoretinal surgery received either alkalinized 0.5% bupivacaine (group B) or a mixture of nonalkalinized 0.5% bupivacaine and 2% lignocaine (group BL), both of which were administered with hyaluronidase, for periocular anesthetic block. The periocular block involved two injections in the extraconal space-one in the lower temporal quadrant and the other in the medial periconal space. The efficacy of the block was graded from 0 to 5 depending on the adequacy of anesthesia and akinesia and the need for local supplementation.
  
  
  RESULTS
  Adequate anesthesia and akinesia (grade 5) were achieved in 72.2% of the patients in group B compared with 57.4% in group BL (P = 0.0003). Intraoperative supplementation was needed in 9.6% and 20.7% of the patients in groups B and BL, respectively (P = 0.0003). Postoperative analgesics were required in 7.4% of the patients in group B and in 15.2% of those in group BL (P = 0.004).
  
  
  CONCLUSIONS
  Alkalinized 0.5% bupivacaine provides better quality of anesthesia than does the mixture of nonalkalinized 0.5% bupivacaine and 2% lignocaine for patients undergoing primary vitreoretinal surgery.
authors.affiliation: Vitreoretinal Service, Sankara Nethralaya, Vision Research Foundation, Chennai, India. mdsaaa35@giasmd01.vsnl.net.in
authors.forename: Tarun
authors.initials: T
authors.lastname: Sharma
authors.forename: Lingam
authors.initials: L
authors.lastname: Gopal
authors.forename: Mahesh P
authors.initials: MP
authors.lastname: Shanmugam
authors.forename: Pramod
authors.initials: P
authors.lastname: Bhende
authors.forename: Joshua
authors.initials: J
authors.lastname: George
authors.forename: Tapan K
authors.initials: TK
authors.lastname: Samanta
authors.forename: Bickol N
authors.initials: BN
authors.lastname: Mukesh
mesh_terms: D000468:Alkalies; D000772:Anesthesia, Local / Q000379:methods*; D019162:Anesthetics, Combined; D000779:Anesthetics, Local / Q000008:administration & dosage* / Q000737:chemistry; D002045:Bupivacaine / Q000008:administration & dosage* / Q000737:chemistry; D004311:Double-Blind Method; D005128:Eye Diseases / Q000601:surgery*; D005260:Female; D006801:Humans; D006821:Hyaluronoglucosaminidase / Q000008:administration & dosage; D006863:Hydrogen-Ion Concentration; D008012:Lidocaine / Q000008:administration & dosage* / Q000737:chemistry; D008297:Male; D008875:Middle Aged; D009407:Nerve Block / Q000379:methods; D011446:Prospective Studies; D012164:Retinal Diseases / Q000601:surgery*; D014822:Vitreous Body / Q000601:surgery*
chemical_list: D000468:Alkalies; D019162:Anesthetics, Combined; D000779:Anesthetics, Local; D008012:Lidocaine; D006821:Hyaluronoglucosaminidase; D002045:Bupivacaine