Nitrous Oxide for Pain Management During In-office Transcervical Sterilization

Hysteroscopic permanent sterilization with Essure® is increasingly performed in the
outpatient setting. No optimal outpatient analgesia regimen has been identified for the
Essure® procedure. The investigators propose a study of inhaled nitrous oxide administered
with oxygen, hereafter referred to as nitrous oxide (NO), as an intervention to lower pain
experienced during the in-office procedure. The investigators hypothesize that, compared to
standard oral medications, inhaled NO will decrease patient anxiety associated with the
in-office procedure, as well as increase patient satisfaction and provider perceived ease of
device insertion.

Women presenting to the clinic for family planning will receive our standard counseling on
all forms of contraception, including short and long acting reversible contraception, and
methods for permanent sterilization. Once the patient decides to have a sterilization
procedure with the transcervical approach (Essure® procedure), she will undergo the standard
pre-procedure evaluation, which includes a complete history, appropriate physical
examination including pelvic examination, and urine pregnancy test.

Eligible women interested in sterilization will be advised of the study as an investigation
evaluating nitrous oxide as an alternative to our current oral sedation pain management for
in-office procedures. If they choose hysteroscopic sterilization, they will undergo informed
consent for the Essure® procedure. Providers will assess patient eligibility criteria for
possible enrollment into the study. If patients are eligible and choose to participate in
the research study, consent for participation will be obtained. At this time patients will
be randomized to treatment group based on a predetermined randomization scheme. For this
research study comparing the use of NO versus oral pain medications, the NO group will
receive two placebo pills and the standard group will receive one 5/325 mg oral tablet of
Vicodin and one 1 mg oral tablet of lorazepam 30 minutes prior to the procedure. The
standard care group will receive oxygen (instead of NO) during the procedure. All
participants will receive 30 mg of intramuscular ketorolac 30 minutes prior to the
procedure.

NO or oxygen will be administered via a scented nasal mask to blind patients to the
intervention. NO can be titrated up to a concentration of 70% nitrous oxide and 30% oxygen
based on desired analgesic effects per a predetermined sedation scale as part of the
University of New Mexico Center for Reproductive Health (UNM CRH) nitrous administration
protocol. All patients will be monitored with a pulse-oximeter. The patient will be fitted
to their mask once the procedure is ready to begin. A single nurse will administer nitrous
oxide and oxygen for all procedures. Every study patient will receive a minimum of 3 minutes
of oxygen at the end of the procedure to minimize the side effects of NO. Additional oxygen
will be administered as needed if a patient is experiencing residual effects of NO.

Prior to the procedure and study medications, patients will complete patient information and
demographics questionnaire and will receive instruction on the 0-100mm visual analogue scale
(VAS) and Spielberger State-Trait Anxiety Inventory (STAI). A baseline pain score will be
recorded using the 0-100mm VAS with anchors 0 equals no pain and 100 equals worst pain
imaginable, as well as baseline anxiety level using the STAI. At placement of the
paracervical block and deployment of the second device coil, pain will be assessed again
with the same 0-100mm VAS. At 3 to 5 minutes following completion of the procedure, maximal
pain experienced during transcervical sterilization will be assessed by the patient. Prior
to discharge from the clinic, the patient will rate her pain level using the same 0-100mm
VAS, rate her level of anxiety with the procedure using the same STAI, and rate her overall
satisfaction with the procedure measured using a 5-point Likert scale.

Immediately after the procedure, the physician will complete a 0-100mm VAS on ease of
insertion of the sterilization devices with anchors 0 equals no difficulty and 100 equals
very difficult. The physician will also complete a 0-100mm VAS on hysteroscopic procedure
difficulty with anchors 0 equals no difficulty and 100 equals very difficult.

The standard transcervical sterilization procedure is not being evaluated in this study.
After patients complete the procedure, they are contacted approximately 75 days from the
procedure date to schedule a confirmatory test, hysterosalpingogram, which is required at 90
days to demonstrate successful sterilization.

Inclusion Criteria:

- Premenopausal women desiring permanent sterilization and have chosen to proceed with
a transcervical sterilization approach

- Speaks English or Spanish

- If relying on state or federal funding for sterilization, must have appropriate
federal consents signed 30 days prior to the sterilization procedure

- Agrees to either a hormonal endometrial preparation prior to the procedure or
schedule the procedure during the follicular phase (days 5 through 12) of their
menstrual cycle

- Sexually active who agrees to contraception for 3 months post procedure, including
condoms, followed by a hysterosalpingogram (HSG) for confirmation of fallopian tubal
occlusion.

Exclusion Criteria:

- With contraindications for nitrous oxide including: respiratory infection, chronic
obstructive pulmonary disease (COPD), intoxication or use of street drugs, inability
to breathe through their nose.

- Have taken narcotic pain medications prior to coming to their appointment

- Unsure about desire to end fertility

- History of pelvic inflammatory disease in the past 3 months

- Pregnancy or suspicion of pregnancy

- Delivery or termination of a pregnancy within the last 6 weeks

- Known allergy to contrast

- Uterine anomalies

- Previous tubal surgery

- Cervical or endometrial cancer

- Allergy to Vicodin, lorazepam, or lidocaine.