title: Inhalation analgesia with nitrous oxide versus other analgesic techniques in hysteroscopic polypectomy: a pilot study.
abstract: OBJECTIVE
  To show the decrease in pain and better tolerance to inhalation analgesia with a 50% equimolar mixture of nitrogen protoxide and oxygen in hysteroscopic polypectomy compared with paracervical anesthesia and a control group.
  
  
  METHODS
  One hundred six patients scheduled for office hysteroscopy and polypectomy were divided into the following 3 groups: the control group, the nitrous oxide group, and the paracervical infiltration group. Patients were assigned sequentially (Canadian Task Force classification II-1).
  
  
  METHODS
  The study took place in a hysteroscopy outpatient clinic under the supervision of a gynecologist and 2 nurses trained to cooperate in the trial.
  
  
  METHODS
  One hundred six women from Area III of Madrid Community, Spain, who had been diagnosed with endometrial polyps at a gynecology office and were scheduled for office hysteroscopy and polypectomy agreed to participate in the study.
  
  
  METHODS
  Patients in group 1 (control group) received no treatment. Group 2 received inhaled nitrous oxide and group 3 paracervical infiltration with 1% lidocaine.
  
  
  RESULTS
  Pain was assessed using the visual analog scale (0-10). Pain perceived by patients was lower in the nitrous Oxide group (mean: 3.55 ± 0.60, median: 3) versus the control group (mean: 5.49 ± 1.88, median: 6, p < .05) and the paracervical infiltration group (mean: 4.22 ± 1.73, median: 5). Tolerance to pain, assessed by the medical staff using qualitative variables, was bad for the control group, very good for the nitrous oxide group, and good for the paracervical infiltration group (p < .05). There were no complications in 82% of the patients in the nitrous oxide group, whereas in the paracervical infiltration group, there were complications in more than 50% of the patients. No severe complications occurred.
  
  
  CONCLUSIONS
  Nitrous oxide is a safe and effective analgesic technique for polipectomy office hysteroscopy compared with the paracervical infiltration and control groups.
authors.affiliation: Department of Obstetrics and Gynecology, Hospital Universitario Príncipe de Asturias, Madrid, Spain. Electronic address: cristinadelvallerubido@gmail.com.
authors.forename: Cristina
authors.initials: C
authors.lastname: Del Valle Rubido
authors.affiliation: Department of Obstetrics and Gynecology, Hospital Universitario Príncipe de Asturias, Madrid, Spain.
authors.forename: Juan Antonio
authors.initials: JA
authors.lastname: Solano Calvo
authors.affiliation: Department of Pharmacology, Hospital Universitario Príncipe de Asturias, Madrid, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Rodríguez Miguel
authors.affiliation: Department of Obstetrics and Gynecology, Hospital Universitario Príncipe de Asturias, Madrid, Spain.
authors.forename: Juan José
authors.initials: JJ
authors.lastname: Delgado Espeja
authors.affiliation: Department of Obstetrics and Gynecology, Hospital Universitario Príncipe de Asturias, Madrid, Spain.
authors.forename: Jerónimo
authors.initials: J
authors.lastname: González Hinojosa
authors.affiliation: Department of Obstetrics and Gynecology, Hospital Universitario Príncipe de Asturias, Madrid, Spain.
authors.forename: Álvaro
authors.initials: Á
authors.lastname: Zapico Goñi
mesh_terms: D000280:Administration, Inhalation; D000328:Adult; D000700:Analgesics / Q000008:administration & dosage*; D004717:Endometrium / Q000601:surgery*; D005260:Female; D006801:Humans; D015907:Hysteroscopy / Q000009:adverse effects / Q000379:methods*; D008012:Lidocaine / Q000008:administration & dosage*; D009609:Nitrous Oxide / Q000008:administration & dosage*; D010147:Pain Measurement; D010865:Pilot Projects; D011127:Polyps / Q000601:surgery*; D011247:Pregnancy; D016896:Treatment Outcome
chemical_list: D000700:Analgesics; D008012:Lidocaine; D009609:Nitrous Oxide
keywords: Analgesia; Endometrial polyp; Hysteroscopy; Nitrous oxide; Polypectomy