title: A double-blind, randomized controlled trial of the use of a 50:50 mixture of nitrous oxide/oxygen in legal abortions.
abstract: BACKGROUND
  The study was conducted to evaluate the effectiveness of oxygen/nitrous oxide (O(2)/N(2)O) in elective abortions by vacuum aspiration with paracervical block and intravenous paracetamol.
  
  
  METHODS
  This single-center double-blinded randomized study tested O(2)/N(2)O (n=36) and placebo (air, n=36) for additional analgesia in elective abortions with paracervical block and intravenous paracetamol. We assessed intra- and postoperative pain according to both a visual analogic scale rated from 0 to 10 and postoperative analgesic requirements.
  
  
  RESULTS
  Mean (±SD) intraoperative, immediate postoperative and late postoperative pain did not differ significantly for patients with O(2)/N(2)O and with air [3.4±2.6 vs. 3.7±3.05 (p=.75), 1.89±2.4 vs. 1.56±2.03 (p=.78), 0.5±0.8 vs. 0.75±1.2 (p=.45)]. The number of patients with scores for low (0-4), moderate (4-7) and severe (7-10) intraoperative, immediate postoperative and late postoperative pain did not differ significantly between the groups. Total adverse effects were significantly higher in the O(2)/N(2)O group [35/180 (19.4%) vs. 18/180 (10%), p=.01].
  
  
  CONCLUSIONS
  O(2)/N(2)O did not reduce intraoperative or postoperative pain in elective abortions by vacuum aspiration with paracervical analgesia and intravenous paracetamol, and its adverse effect rate was substantial.
authors.affiliation: Department of Obstetrics and Gynaecology, La Conception University Hospital, Marseille, 13005, France. aubert.agostini@ap-hm.fr
authors.forename: Aubert
authors.initials: A
authors.lastname: Agostini
authors.forename: Julia
authors.initials: J
authors.lastname: Maruani
authors.forename: Pascale
authors.initials: P
authors.lastname: Roblin
authors.forename: Jocelyne
authors.initials: J
authors.lastname: Champion
authors.forename: Ludovic
authors.initials: L
authors.lastname: Cravello
authors.forename: Marc
authors.initials: M
authors.lastname: Gamerre
mesh_terms: D000029:Abortion, Legal; D000328:Adult; D018712:Analgesics, Non-Narcotic / Q000627:therapeutic use*; D000772:Anesthesia, Local; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D009609:Nitrous Oxide / Q000009:adverse effects* / Q000627:therapeutic use*; D010100:Oxygen / Q000008:administration & dosage; D010146:Pain / Q000517:prevention & control*; D010147:Pain Measurement; D055815:Young Adult
chemical_list: D018712:Analgesics, Non-Narcotic; D009609:Nitrous Oxide; D010100:Oxygen