title: Refining paracervical block techniques for pain control in first trimester surgical abortion: a randomized controlled noninferiority trial.
abstract: Our objective was to evaluate two different aspects of the paracervical block (PCB) technique for first trimester surgical abortion, to compare a 3-min wait prior to cervical dilation to no wait and to compare four-site with two-site injection.
  
  
  
  We conducted two consecutive randomized, single-blinded noninferiority trials. In the first trial, women <11 weeks gestational age received a 20-mL 1% buffered lidocaine four-site PCB with either a 3-min wait between PCB injection and dilation or no wait. In the second trial, we compared a four-site with a two-site PCB. We evaluated dilation pain [100-mm visual analogue scale (VAS)] as the primary outcome. Secondary outcomes included pain at additional time points, anxiety, satisfaction and adverse events.
  
  
  
  Both trials fully enrolled (total n=332). Results were inconclusive as to whether no wait was noninferior to waiting 3-min prior to cervical dilation for dilation pain [VAS: 63 mm (SD, 24 mm) vs. 56 mm (SD, 32mm)] and as to whether a two-site PCB was noninferior to a four-site block [VAS: 68 mm (SD, 21 mm) vs. 60 mm (SD, 30 mm)]. Noninferiority analysis was inconclusive because the confidence interval of the mean pain score difference between groups included the predefined inferiority margin of 13-mm pain difference. Superiority analysis showed the four-site PCB to be superior to the two-site PCB.
  
  
  
  It remained inconclusive whether a 3-min wait time between PCB and cervical dilation provides noninferior pain control for first trimester surgical abortion. However, a four-site PCB appeared to be superior to a two-site PCB.
  
  
  
  It remained inconclusive whether a 3-min wait time between PCB and cervical dilation or using a two-site instead of a four-site PCB provided noninferior pain control for first trimester surgical abortion. This study did not assess whether the combination of the two separate factors provides additive benefit.
authors.affiliation: Department of Obstetrics and Gynecology, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, UHN 50, Portland, OR 97239, USA. Electronic address: rerenner@bluewin.ch.
authors.forename: Regina-Maria
authors.initials: RM
authors.lastname: Renner
authors.affiliation: Department of Obstetrics and Gynecology, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, UHN 50, Portland, OR 97239, USA.
authors.forename: Alison B
authors.initials: AB
authors.lastname: Edelman
authors.affiliation: Department of Obstetrics and Gynecology, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, UHN 50, Portland, OR 97239, USA.
authors.forename: Mark D
authors.initials: MD
authors.lastname: Nichols
authors.affiliation: Department of Obstetrics and Gynecology, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, UHN 50, Portland, OR 97239, USA.
authors.forename: Jeffrey T
authors.initials: JT
authors.lastname: Jensen
authors.affiliation: Division of Biostatistics, Department of Public Health & Preventive Medicine, Oregon Health & Science University, Portland, OR 97239, USA.
authors.forename: Jeong Y
authors.initials: JY
authors.lastname: Lim
authors.affiliation: Department of Obstetrics and Gynecology, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, UHN 50, Portland, OR 97239, USA.
authors.forename: Paula H
authors.initials: PH
authors.lastname: Bednarek
mesh_terms: D000028:Abortion, Induced / Q000379:methods*; D000328:Adult; D000773:Anesthesia, Obstetrical / Q000379:methods*; D000779:Anesthetics, Local / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D007747:Labor Stage, First; D008012:Lidocaine / Q000627:therapeutic use*; D009922:Oregon; D010146:Pain / Q000188:drug therapy*; D059408:Pain Management; D010147:Pain Measurement; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D016037:Single-Blind Method; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D000779:Anesthetics, Local; D008012:Lidocaine
keywords: Abortion; Analgesia; Pain control; Paracervical block