To evaluate whether inhaled nitrous oxide with oxygen (N2O/O2) is associated with less pain compared to oral sedation for pain management during in-office hysteroscopic sterilization.
This double blinded randomized controlled trial enrolled women undergoing in-office hysteroscopic sterilization. All participants received pre-procedure intramuscular ketorolac and a standardized paracervical block. The intervention group also received N2O/O2 via a nasal mask titrated to a maximum 70%:30% mixture by a nurse during the procedure and placebo pills pre-procedure and the active control group received inhaled O2 during the procedure and 5/325 mg hydrocodone/acetaminophen and 1 mg lorazepam pre-procedure. The primary outcome was maximum procedure pain on a 100 mm Visual Analog Scale (VAS with anchors at 0 = no pain and 100 = worst imaginable pain) assessed 3–5 min post procedure. Thirty women per treatment arm were required to detect a clinically significant pain difference of 20 mm.
Seventy-two women, 36 per study arm, were randomized. Mean age of participants was 34.1±5.7 years and mean BMI was 30.1±6.6 kg/m2. Mean maximum procedure pain scores were 22.8±27.6 mm and 54.5±32.7 mm for intervention and control groups, respectively (p<.001). Most study participants (97%) stated N2O/O2 should be offered for gynecologic office procedures and 86% would pay for it if not a covered benefit.
N2O/O2 decreased pain with in-office hysteroscopic sterilization compared to oral sedation and is an effective pain management option for this procedure.
Given its safety and favorable side effect profile, N2O/O2 can be used for pain management for in-office hysteroscopic sterilization and adds a safe, easily administered option to currently available strategies.
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Published online: September 09, 2016
Accepted: September 4, 2016
Received in revised form: August 31, 2016
Received: May 27, 2016
☆Clinical Trial Registration: ClinicalTrials.gov, www.clinicaltrials.gov, NCT02312739.
© 2016 Elsevier Inc. All rights reserved.