Nitrous Oxide for Pain Management during In-office Hysteroscopic Sterilization

Objectives: To determine if inhaled nitrous oxide with oxygen (NOS) is superior to oral sedation for pain management during in-office hysteroscopic sterilization. Methods: This double blinded randomized controlled trial enrolled women undergoing in-office hysteroscopic sterilization. The intervention group received NOS titrated to a maximum 70%:30% NO:O2 mixture and placebo pills 30 minutes prior to the procedure. The control group received inhaled O2 during the procedure and 5/325mg hydrocodone/acetaminophen and 1mg lorazepam 30 minutes prior to the procedure. The primary outcome was maximum procedural pain, assessed on a 100mm Visual Analogue Scale (VAS) 3 minutes post procedure. A sample size of 30 women per treatment arm was required to detect a clinically significant pain difference of 20mm on the VAS. Results: 72 women, 36 per study arm, were randomized in order to account for unsuccessful bilateral coil placement and drop out after randomization. Two women in the study group and 6 in the control group were excluded due to unsuccessful bilateral coil placement. Mean age of participants was 34.1 ± 5.7 years and mean BMI was 30.1 ± 6.6 kg/m2. Mean maximum procedural pain scores were 22.8 ± 27.6 mm and 54.5 ± 32.7 mm for study and control groups, respectively (p < 0.001). Most study participants (97%) stated NOS should be offered for gynecologic office procedures and 86% would pay extra for NOS if it were not a covered benefit. Conclusions: NOS significantly decreased pain with in-office hysteroscopic sterilization compared to PO sedation. Given its safety and favorable side effect profile, routine availability of NOS should be considered for in-office hysteroscopic sterilization.Society of Family Planning Bayer PharmaceuticalsBiomedical SciencesMastersUniversity of New Mexico. Biomedical Sciences Graduate ProgramSingh, Rameet MD MPHEspey, Eve MD MPHMishra, Shiraz MBBS Ph