Use of Nitrous Oxide During Office Hysteroscopy

NCT07074795 | Active Not Recruiting

• 1 other identifier: 0002-24mhmc
• Study Type: interventional
• Target: 400
• Locations: 1 country
• Sites: 1

Brief Summary

The goal of this clinical trial is to assess the use of inhaled nitrous oxide during office hysteroscopy. The main questions it aims to answer are:

• Does it reduce pain during the procedure?
• Does it increase the success rate?
• Does it improve patient satisfaction?
• Does it reduce anxiety?
• Which populations benefit more (e.g., parity, menopausal status, number of previous surgeries, type and duration of procedure, and type of device)? Participants will be asked about their pain levels during the procedure, as well as their anxiety levels. All responses will be recorded. Written informed consent will be obtained prior to initiation.

Conditions

Abnormal Uterine Bleeding; Postmenopausal Bleeding; Endometrial Polyps; Retained Products of Conception; Uterine Fibroids; Intrauterine Adhesions

Keywords

Inhaled nitrous oxide; Office hysteroscopy; Pain management; Visual analogue scale (VAS); Anxiety reduction; Gynecology

Outcome Measures

Primary Outcomes (1)

• Comparison of Pain During Office Hysteroscopy Between Inhaled Nitrous Oxide (Treatment Group) and Ambient Air (Placebo Group)

  The difference in pain between the two groups will be assessed using the Visual Analog Scale (VAS), ranging from 0 to 10, where 0 indicates no pain and 10 represents the worst imaginable pain. Pain scores will be collected at three time points throughout the procedure : uterine entry, during the procedure, and immediately after its completion.

  Periprocedural (start to end of the hysteroscopy procedure)

Secondary Outcomes (3)

• Incidence of side effects related to inhaled substance

  Periprocedural (start to end of the hysteroscopy procedure)

• Procedure completion

  Periprocedural

• Patient satisfaction with the procedure

  Immediately post-procedure

Other Outcomes (2)

• Subgroup differences in pain reduction associated with nitrous oxide during office hysteroscopy

  Periprocedural (start to end of the hysteroscopy procedure)

• Pre-procedural anxiety level assessed using modified State-Trait Anxiety Inventory (STAI)

  Immediately before the procedure

Study Arms (2)

treatment- inhaled nitrous oxide

ACTIVE COMPARATOR

Participants in the Nitrous Oxide group will inhale a fixed 50:50 mixture of nitrous oxide (N₂O) and oxygen (O₂), starting one minute prior to the procedure and continuing throughout its duration. The gas is administered via a self-administered demand-valve face mask connected to the Blendox system (Ambulanc®, Italy).

Procedure: Inhalation of Nitrous Oxide (N₂O) during Office Operative Hysteroscopy

Inhaled ambient air control group

PLACEBO COMPARATOR

Participants in the control group will inhale ambient air starting one minute prior to the procedure and will continue inhalation throughout its duration. The ambient air is administered via a self-administered demand-valve face mask connected to the Blendox system (Ambulanc®, Italy).

Procedure: inhalation of ambient air during office hysteroscopy

Interventions

Inhalation of Nitrous Oxide (N₂O) during Office Operative Hysteroscopy PROCEDURE

Inhaled nitrous oxide

treatment- inhaled nitrous oxide

inhalation of ambient air during office hysteroscopy PROCEDURE

inhalation of ambient air

Inhaled ambient air control group

Eligibility Criteria

• Age: 18 Years+
• Gender Eligibility Details: Self-identified females assigned female at birth are eligible to participate.
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Women aged ≥18 years Scheduled to undergo operative office hysteroscopy for clinical indications

You may not qualify if:

• Any contraindications to N₂O, including:
• Pneumothorax Significant chronic obstructive pulmonary disease (COPD) Upper airway obstruction Bowel obstruction Middle ear pathology (e.g., recent ear surgery or active ear infection) Severe recent intraocular gas injection Severe vitamin B12 deficiency Known hypersensitivity to N₂O
• Women who will decline randomization or unable to provide informed consent.

Sponsors & Collaborators

• Maaynei Hayesha Medical Center: lead

Study Sites (1)

Mayanei HaYeshua Medical Center

Bnei Brak, 51544, Israel

Location

Related Publications (2)

• Likis FE, Andrews JC, Collins MR, Lewis RM, Seroogy JJ, Starr SA, Walden RR, McPheeters ML. Nitrous oxide for the management of labor pain: a systematic review. Anesth Analg. 2014 Jan;118(1):153-67. doi: 10.1213/ANE.0b013e3182a7f73c.

  PMID: 24356165 BACKGROUND

• Buhre W, Disma N, Hendrickx J, DeHert S, Hollmann MW, Huhn R, Jakobsson J, Nagele P, Peyton P, Vutskits L. European Society of Anaesthesiology Task Force on Nitrous Oxide: a narrative review of its role in clinical practice. Br J Anaesth. 2019 May;122(5):587-604. doi: 10.1016/j.bja.2019.01.023. Epub 2019 Feb 22.

  PMID: 30916011 BACKGROUND

Related Links

• Similar study principle evaluating inhaled nitrous oxide vs oral analgesia during office hysteroscopy

MeSH Terms

Conditions

Metrorrhagia; Leiomyoma; Gynatresia; Agnosia

Condition Hierarchy (Ancestors)

Uterine Hemorrhage; Uterine Diseases; Genital Diseases, Female; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Urogenital Diseases; Genital Diseases; Hemorrhage; Pathologic Processes; Pathological Conditions, Signs and Symptoms; Neoplasms, Muscle Tissue; Neoplasms, Connective and Soft Tissue; Neoplasms by Histologic Type; Neoplasms; Perceptual Disorders; Neurobehavioral Manifestations; Neurologic Manifestations; Nervous System Diseases; Signs and Symptoms

Study Officials

• Tamar Tzur, MD

  Mayanei Hayeshua Medical Center

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: CARE PROVIDER
• Purpose: TREATMENT
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: P.I Dr Tamar Tzur. Senior gynecologist at Maaynei Hayesha

Model Details: Randomized clinical trial of inhaled nitrous oxide vs inhaled ambient air

Study Record Dates

• First Submitted: June 30, 2025
• First Posted: July 20, 2025
• Study Start: July 1, 2025
• Primary Completion (Estimated): June 1, 2026
• Study Completion (Estimated): June 1, 2026
• Last Updated: July 20, 2025

Record last verified: 2025-07

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL
• Time Frame: De-identified individual participant data (IPD) and supporting information will be made publicly available at the time of primary results publication in a peer-reviewed journal. The data will remain accessible indefinitely via an open-access online repository.
• Access Criteria: The IPD and supporting documents will be accessible to all users via open access. No request or approval will be required. A direct link to the data repository (e.g., Figshare, Zenodo) will be provided in the publication.

Locations

IL (1)