Biomedical Sciences ETDs

Publication Date



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.


Nitrous Oxide, Pain management, Hysteroscopy, Female sterilization, Office procedures


Society of Family Planning Bayer Pharmaceuticals

Document Type




Degree Name

Biomedical Sciences

Level of Degree


Department Name

Biomedical Sciences Graduate Program

First Committee Member (Chair)

Espey, Eve MD MPH

Second Committee Member

Mishra, Shiraz MBBS PhD

Third Committee Member