title: A comparison of lidocaine 2% with levobupivacaine 0.75% for sub-Tenon's block.
abstract: OBJECTIVE
  To compare the onset of action, and quality of block, of lidocaine 2% with levobupivacaine 0.75% for sub-Tenon's block in patients undergoing cataract surgery.
  
  
  METHODS
  We performed a two-centre trial in 91 patients who were randomized to receive 4 mL of lidocaine 2% (n = 44) or levobupivacaine 0.75% (n = 47) for sub-Tenon's block, both with hyaluronidase 15 IUmL(-1). Onset of akinesia was assessed every 2 min for 10 min. Numbers of patients requiring supplementary injections to achieve clinically satisfactory akinesia or rescue analgesia were recorded. Data were analyzed with Fisher's exact test, U-test and t-test where appropriate. Results were considered significant when P < 0.05.
  
  
  RESULTS
  The speed of onset was statistically significantly faster for lidocaine compared to levobupivacaine (3.02 vs. 5.06 min, P < 0.001). There was no statistical difference in number of patients requiring a supplementary injection of local anaesthetic (levobupivacaine 3 vs. lidocaine 0, P = 0.24), rescue analgesia with topical tetracaine (levobupivacaine 0 vs. lidocaine 2, P = 0.5), or ocular akinesia scores at the completion of surgery (lidocaine 1.4 vs. levobupivacaine 1.6, P = 0.12). Pain scores measured by a verbal analogue scale were not significantly different for injection, perioperatively or postoperatively.
  
  
  CONCLUSIONS
  Both agents produce a rapid onset of anaesthesia when used for sub-Tenon's block. The difference between the two agents, although statistically significant, is not clinically important.
authors.affiliation: St James's University Hospital, Leeds, UK.
authors.forename: H A
authors.initials: HA
authors.lastname: McLure
authors.forename: C M
authors.initials: CM
authors.lastname: Kumar
authors.forename: S
authors.initials: S
authors.lastname: Ahmed
authors.forename: A
authors.initials: A
authors.lastname: Patel
mesh_terms: D000368:Aged; D000779:Anesthetics, Local; D002045:Bupivacaine / Q000031:analogs & derivatives; D002387:Cataract Extraction; D004311:Double-Blind Method; D005133:Eye Movements / Q000187:drug effects; D005260:Female; D006801:Humans; D000077554:Levobupivacaine; D008012:Lidocaine; D008297:Male; D009407:Nerve Block; D010147:Pain Measurement / Q000187:drug effects
chemical_list: D000779:Anesthetics, Local; D008012:Lidocaine; D000077554:Levobupivacaine; D002045:Bupivacaine