title: Nitrous oxide vs periprostatic nerve block with 1% lidocaine during transrectal ultrasound guided biopsy of the prostate: a prospective, randomized, controlled trial.
abstract: OBJECTIVE
  We compared the efficacy of Entonox (BOC Gases, Manchester, United Kingdom), a mixture of 50% nitrous oxide and oxygen, with periprostatic infiltration of 1% lidocaine to provide analgesia during transrectal ultrasound (TRUS) guided biopsy of the prostate.
  
  
  METHODS
  The study included 235 consecutive men undergoing TRUS guided biopsy of the prostate for elevated prostate specific antigen or abnormal digital rectal examination. Patients were randomized to 3 groups, including group 1-84 controls who did not receive any form of analgesia prior to the procedure, group 2-75 who received periprostatic infiltration with 10 ml 1% lidocaine with biopsies performed 5 minutes after infiltration and group 3-76 who received Entonox for 2 minutes through a breath activated device prior to the procedure and thereafter according to patient preference. All patients were asked to indicate the level of pain experienced before and after the procedure on a 10 cm, nonnumerical, horizontal visual analog score. Results were analyzed using 1-way ANOVA.
  
  
  RESULTS
  Mean patient age was 68.8, 64.9 and 65.2 years, and mean visual analog score was 2.9, 1.6 and 2.2 in groups 1 to 3, respectively. Patients in groups 2 (1% lidocaine infiltration) and 3 (Entonox) experienced significantly less pain during the procedure compared with group 1 controls (p <0.001 and 0.028, respectively). There was no statistical difference in pain scores between groups 2 and 3 (p = 0.08).
  
  
  CONCLUSIONS
  Inhalation of Entonox or periprostatic infiltration with 1% lidocaine can be used for analgesia during TRUS guided biopsy of the prostate since each provides significant and similar pain relief.
authors.affiliation: Department of Urology, Basquill House, Stepping Hill Hospital, Stockport SK2 7JE, UK. armanikan@aol.com
authors.forename: Ramaswamy
authors.initials: R
authors.lastname: Manikandan
authors.forename: Shalom J
authors.initials: SJ
authors.lastname: Srirangam
authors.forename: Stephen C W
authors.initials: SC
authors.lastname: Brown
authors.forename: Patrick H
authors.initials: PH
authors.lastname: O'Reilly
authors.forename: Gerald N
authors.initials: GN
authors.lastname: Collins
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000769:Anesthesia, Inhalation; D000772:Anesthesia, Local; D019162:Anesthetics, Combined; D001707:Biopsy, Needle; D019160:Endosonography; D006801:Humans; D008012:Lidocaine; D008297:Male; D008875:Middle Aged; D009407:Nerve Block; D009609:Nitrous Oxide; D010100:Oxygen; D010147:Pain Measurement; D011446:Prospective Studies; D011467:Prostate / Q000000981:diagnostic imaging / Q000187:drug effects / Q000473:pathology*; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*
chemical_list: D019162:Anesthetics, Combined; C001147:Entonox; D008012:Lidocaine; D009609:Nitrous Oxide; D010100:Oxygen