Nitrous Oxide for External Cephalic Version

Overview

This study seeks to determine the effectiveness of nitrous oxide in reducing the anxiety and pain associated with external cephalic version (ECV); a maneuver to turn the fetus from breech to cephalic position.

Full Title of Study: “Randomized Controlled Trial of Nitrous Oxide Analgesia in External Cephalic Version (ECV)”

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Randomized
    • Intervention Model: Parallel Assignment
    • Primary Purpose: Treatment
    • Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
  • Study Primary Completion Date: February 14, 2019

Detailed Description

Study Procedures:

Potential subjects will be identified as they are scheduled to undergo ECV at the UNC Department of Obstetrics and Gynecology. Subjects will be enrolled in the study by one of the study investigators. Details of the study will be reviewed with potential subjects and those wishing to enroll in the study will be consented for the study by one of the study investigators. Once enrolled participants will be randomized to receive either a mixture of 50% nitrous oxide in 50% oxygen or 100% oxygen, both of which will be delivered via the Nitronox apparatus. Demographic variables will be recorded for each participant at the time they are enrolled in the study

The Nitronox apparatus will be set up to deliver either 50% nitrous oxide in 50% oxygen or 100% oxygen by an anesthesia provider covering labor and delivery who is not involved in the study. The Nitronox device will be covered to prevent participants, study investigators and obstetricians performing the procedure from knowing whether nitrous oxide is being delivered. Nitrous oxide is odorless and colorless, so in that way is indistinguishable from oxygen.

Participants will be prepared for ECV according to current protocols for ECV at UNC. IV access will be obtained and tocolytic agents will be given according to current practice and protocols. Monitoring of maternal and fetal vital signs will be done according to current protocols.

Immediately before an ECV attempt participants will breathe through the facemask of the Nitronox device for 30 seconds and will then be free to use the device ad lib during the ECV attempt. Immediately following each attempt, while fetal monitoring is occurring, the participants will be asked to rate their maximum pain score during the previous attempt. They will also be asked to rate their current level of anxiety. This process will be repeated for any further ECV attempts.

At conclusion of all ECV attempts, while fetal monitoring is occurring, the participants will be asked to rate their current level of pain, their satisfaction with the procedure and about any side effects they experienced (nausea, vomiting, dizziness, headache, other). Participants will continue to be monitored on labor and delivery as current protocol dictates, typically 30 minutes of maternal and fetal monitoring if there are no complications and fetal status is reassuring.

Following the procedure, the obstetrician who performed the procedure will be asked to rate how difficult they felt it was to perform the procedure and to rate how much they felt the analgesic provided assisted in performing the procedure. They will also be asked to indicate whether they thought the patient was in the treatment or placebo arm of the study. This will be recorded to address the adequacy of blinding.

All study variables will be assessed and recorded by one of the study investigators to ensure consistency in data collection.

Interventions

  • Drug: Nitrous Oxide
    • 50% nitrous oxide/50% oxygen via Nitronox delivery device
  • Other: Placebo
    • 100% oxygen via Nitronox delivery device

Arms, Groups and Cohorts

  • Experimental: Nitrous Oxide
    • Patients will receive nitrous oxide during the version procedure.
  • Placebo Comparator: Oxygen
    • Patients will receive placebo (100% oxygen) during the version procedure.

Clinical Trial Outcome Measures

Primary Measures

  • Mean Pain Score Experienced During Version
    • Time Frame: During each version procedure, a total average of up to approximately 30 minutes
    • Pain scores will be collected following each version attempt using an 11 point scale (with 0 being no pain at all; 10 being worst pain imaginable), ranging from 0 to 10. Higher scores indicate more pain, lower scores indicate less pain. If more than one attempt, pain scores will be averaged to obtain a single score for the entire procedure.

Secondary Measures

  • Mean Anxiety Score Experienced During Version
    • Time Frame: During each version procedure, a total average of up to approximately 30 minutes
    • Anxiety scores will be collected following each version attempt using an 11 point scale (0 being not at all anxious; 10 being extremely anxious), ranging from 0 to 10. Higher scores indicate more anxiety, lower scores indicate less anxiety. If more than one attempt, anxiety scores will be averaged to obtain a single score for the entire procedure.
  • Mean Post-procedure Pain Score
    • Time Frame: Immediately Post-procedure, within approximately 15 minutes of final version attempt
    • Pain scores will be collected following completion of the version using an 11 point scale (0 being no pain at all; 10 being worst pain imaginable), ranging from 0 to 10. Higher scores indicate more pain, lower scores indicate less pain.
  • Mean Post-procedure Patient Satisfaction Score
    • Time Frame: Immediately Post-procedure, within approximately 15 minutes of final version attempt
    • Satisfaction will be assessed following the procedure using an 11 point scale (0 being not at all satisfied; 10 being extremely satisfied), ranging from 0 to 10. Higher scores indicate more satisfaction, lower scores indicate less satisfaction.
  • Mean Post-procedure Provider Assessed Level of Difficulty Score
    • Time Frame: Immediately Post-procedure, within approximately 15 minutes of final version attempt
    • Following the procedure, the obstetric provider performing the procedure will rate the ease of procedure on a 1-10 scale (1 being very easy and 10 being extremely difficult), ranging from 1 to 10. Higher scores indicate more difficulty, lower scores indicate less difficulty. A 10 point scale was used for this outcome, while an 11 point scale was used for the other 4 outcome measures (pain, anxiety, post-procedure pain and satisfaction).

Participating in This Clinical Trial

Inclusion Criteria

  • Female 18 years or greater
  • Scheduled to undergo external cephalic version due to singleton breech presentation
  • Not scheduled to have spinal or epidural anesthesia during the version procedure
  • American Society of Anesthesiology (ASA) Physical Status 1, 2 or 3.
  • Able to provide informed consent and adhere to study protocol

Exclusion Criteria

  • Current or historical evidence of any clinically significant disease or condition, especially cardiovascular or neurological conditions that, in the opinion of the Investigator, may increase the risk of exposure to nitrous oxide or complicate the subject's post-procedural course.
  • Significant medical conditions or laboratory results that, in the opinion of the Investigator, indicate an increased vulnerability to study drugs and procedures.

Gender Eligibility: Female

Only females will participate because only females can be pregnant.

Minimum Age: 18 Years

Maximum Age: N/A

Are Healthy Volunteers Accepted: Accepts Healthy Volunteers

Investigator Details

  • Lead Sponsor
    • University of North Carolina, Chapel Hill
  • Provider of Information About this Clinical Study
    • Sponsor
  • Overall Official(s)
    • Kathleen A. Smith, MD, FASA, Principal Investigator, University of North Carolina, Chapel Hill

References

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ACOG Committee on Obstetric Practice. ACOG Committee Opinion No. 340. Mode of term singleton breech delivery. Obstet Gynecol. 2006 Jul;108(1):235-7.

Fok WY, Chan LW, Leung TY, Lau TK. Maternal experience of pain during external cephalic version at term. Acta Obstet Gynecol Scand. 2005 Aug;84(8):748-51.

Lavoie A, Guay J. Anesthetic dose neuraxial blockade increases the success rate of external fetal version: a meta-analysis. Can J Anaesth. 2010 May;57(5):408-14. doi: 10.1007/s12630-010-9278-4. Epub 2010 Feb 3.

Weiniger CF, Ginosar Y, Elchalal U, Sharon E, Nokrian M, Ezra Y. External cephalic version for breech presentation with or without spinal analgesia in nulliparous women at term: a randomized controlled trial. Obstet Gynecol. 2007 Dec;110(6):1343-50.

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. Review. Erratum in: Anesth Analg. 2014 Apr;118(4):885.

Rosen MA. Nitrous oxide for relief of labor pain: a systematic review. Am J Obstet Gynecol. 2002 May;186(5 Suppl Nature):S110-26. Review.

Creeley CE, Olney JW. The young: neuroapoptosis induced by anesthetics and what to do about it. Anesth Analg. 2010 Feb 1;110(2):442-8. doi: 10.1213/ANE.0b013e3181c6b9ca. Epub 2009 Dec 2.

Jevtovic-Todorovic V, Hartman RE, Izumi Y, Benshoff ND, Dikranian K, Zorumski CF, Olney JW, Wozniak DF. Early exposure to common anesthetic agents causes widespread neurodegeneration in the developing rat brain and persistent learning deficits. J Neurosci. 2003 Feb 1;23(3):876-82.

Schnabel A, Hahn N, Broscheit J, Muellenbach RM, Rieger L, Roewer N, Kranke P. Remifentanil for labour analgesia: a meta-analysis of randomised controlled trials. Eur J Anaesthesiol. 2012 Apr;29(4):177-85. doi: 10.1097/EJA.0b013e32834fc260.

Muñoz H, Guerra S, Perez-Vaquero P, Valero Martinez C, Aizpuru F, Lopez-Picado A. Remifentanil versus placebo for analgesia during external cephalic version: a randomised clinical trial. Int J Obstet Anesth. 2014 Feb;23(1):52-7. doi: 10.1016/j.ijoa.2013.07.006. Epub 2014 Jan 3.

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