COVID-19 studies are our top priority. For all other studies, we recommend commencing the registration process concurrently with your ethics submission and allowing at least 8 weeks for registration to be completed from date of first submission as we are experiencing 4 week turn-around time in review of submissions and resubmissions. We currently do not have the capacity to expedite reviews.

Note also there are additional delays to review of updates. We appreciate your patience.

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been endorsed by the ANZCTR. Before participating in a study, talk to your health care provider and refer to this information for consumers
Trial registered on ANZCTR

Registration number
Ethics application status
Not yet submitted
Date submitted
Date registered
Date last updated
Date data sharing statement initially provided
Type of registration
Prospectively registered

Titles & IDs
Public title
Methoxyflurane pain relief for awake hysteroscopy.
Scientific title
Methoxyflurane analgesia for conscious hysteroscopy: a double-blind randomised controlled trial.
Secondary ID [1] 300490 0
Nil known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
abnormal uterine bleeding 316168 0
pain relief 316169 0
Condition category
Condition code
Reproductive Health and Childbirth 314462 314462 0 0
Menstruation and menopause
Anaesthesiology 314463 314463 0 0
Pain management

Study type
Description of intervention(s) / exposure
3ml of inhaled methoxyflurane will be given via a Penthrox inhaler over a 10 minute period while a patient has an outpatient/conscious hysteroscopy procedure. The medicine will be self-administered with supervision by a doctor and a nurse.

The fidelity of the administration will be maintained by 1. Uniform medication and placebo preparation within pre-packaged units containing a single inhaler and a 3ml vial of methoxyflurane. 2. The placebo will use the same pre-packaged unit, but instead of the methoxyflurane being poured into the inhaler, a few drops of the medication will be placed on the exterior surface to allow the prominent smell of the medication to contribute to blinding.
Intervention code [1] 316799 0
Treatment: Drugs
Comparator / control treatment
3ml of normal saline through the Penthrox inhaler over a 10 minute period while a patient has an outpatient/consicous hysteroscopy procedure.
Control group

Primary outcome [1] 322791 0
Difference in pain scores via a 0-100mm Visual Analog Scale
Timepoint [1] 322791 0
Immediately during the procedure
Secondary outcome [1] 379800 0
Patient retrospective assessment of the worst pain during the procedure via a 0-100mm Visual Analog Scale.
Timepoint [1] 379800 0
Immediately post procedure
Secondary outcome [2] 379801 0
Patient feelings of stress during the procedure via a 0-100mm Visual Analog Scale
Timepoint [2] 379801 0
Immediately post procedure
Secondary outcome [3] 379802 0
Whether the patient would choose to have a conscious hysteroscopy if she was in the same situation again. This will be assessed via a Likert scale designed for the trial with a multiple choice option of 1. Very Likely, 2. Likely, 3. Not Sure, 4. Probably not 5. Definitely not.
Timepoint [3] 379802 0
Immediately post procedure
Secondary outcome [4] 379803 0
On their individual data collection form, patients will be invited to document a free text description of any unpleasant side effects they experienced. Clinicans will also be invited to provide a free text description of adverse events. We will also list some more common unpleasant side effects and patients can tick a box next to the symptom if they experienced it.
The most commonly described treatment-related adverse events are
- Headache
- Unpleasant dizziness
- Nausea
- Sore throat
- Coughing
- Drowsiness
Timepoint [4] 379803 0
Immediately post procedure
Secondary outcome [5] 379804 0
Patients will be invited to comment on any non-pelvic pain they experienced with the procedure. This will be via a 'yes/no' question box then a line for free text if patients ticked 'yes'.
Timepoint [5] 379804 0
Immediately post procedure
Secondary outcome [6] 379805 0
The percentage of patients who had a successfully completed outpatient hysteroscopy versus those who needed to be referred for a general anaesthetic (inpatient) procedure to complete the task. Where a second procedure is indicated, the reason for that need will be documented by the doctor.
Timepoint [6] 379805 0
Immediately post procedure
Secondary outcome [7] 379806 0
Cervical shock will be defined as reduced patient consciousness with any combination of heart rate bradycardia <50 beats per minute, systolic blood pressure <80 mmHg, diastolic blood pressure <50 mmHg. The data collection form will ask a 'yes/no' question as to whether cervical shock occured and if 'yes', the measures for haemodynamic recovery e.g. medication, positioning manoeuvres or intravenous lfuids will be documented.
Timepoint [7] 379806 0
Within 30 minutes of the procedure

Key inclusion criteria
Patients booked to our hysteroscopy clinic, these patients have already been assessed from gynaecology clinic as suitable candidates for awake/outpatient hysteroscopies. They will be invited to participate in the trial on the day of their hysteroscopy.
Minimum age
18 Years
Maximum age
75 Years
Can healthy volunteers participate?
Key exclusion criteria
Non-fluent English, known renal disease (Creatinine greater than or equal to 1.5 times the upper limit of normal), known liver disease (bilirubin greater than or equal to 2.5 times the upper limit of normal), known sensitivity to fluorinated anaesthetic, known cardiovascular disease, altered consciousness, personal history of malignant hyperthermia, family history of malignant hyperthermia unless personally tested to be negative,

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Opaque envelopes with randomisation, unblinded nurse to prepare the medication outside the treatment room, identical inhaler kits. Identical clear 3ml fluid. Both inhalers will have drops of methoxyflurane applied to the outside of the inhaler to blind for the typical smell of the medication.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Computer-generated random sequence with corresponding envelopes containing the message "Methoxyflurane" or "Normal saline"
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s
The people administering the treatment/s
The people assessing the outcomes
Intervention assignment
Other design features
Phase 4
Type of endpoint(s)
Statistical methods / analysis
Repated measures with ANCOVA model.
Stratification for risk factors for painful insertion (no previous vaginal births, >5 years since last vaginal birth, prior difficult instrumentation or unsuccessful hysteroscopy)
Student's t-test for quantitative variables. Comparisons between arms will use the Wilcoxon rank Sum test. Data will be analysed according to intention to treat.

Recruitment status
Not yet recruiting
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment outside Australia
Country [1] 22342 0
New Zealand
State/province [1] 22342 0

Funding & Sponsors
Funding source category [1] 304908 0
Commercial sector/Industry
Name [1] 304908 0
Douglas Pharmaceuticals
Address [1] 304908 0
2 Te Pai Place, Henderson, Auckland 0610
Country [1] 304908 0
New Zealand
Primary sponsor type
Waikato DHB
Pembroke St
Waikato 3204
New Zealand
Secondary sponsor category [1] 305253 0
Name [1] 305253 0
Address [1] 305253 0
Country [1] 305253 0

Ethics approval
Ethics application status
Not yet submitted
Ethics committee name [1] 305317 0
Health and Disability Ethics Committee
Ethics committee address [1] 305317 0
Ministry of Health
Health and Disability Ethics Committees
PO Box 5013
Wellington 6140
Ethics committee country [1] 305317 0
New Zealand
Date submitted for ethics approval [1] 305317 0
Approval date [1] 305317 0
Ethics approval number [1] 305317 0

Brief summary
Hysteroscopy is often performed on patients while they are awake, while we try to make the procedure comfortable; a degree of pain is usually experienced. This study will be using a medication called methoxyflurane that is commonly used for pain relief for conscious procedures to see whether it is useful for women having hysteroscopies. We will be giving half our study participants an inhaler with methoxyflurane, and another half will have an inhaler without the medication inside. We will then ask both groups questions about how they felt during the procedure and compare the two to see if all women should be offered methoxyflurane with their hysteroscopy.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 99974 0
Dr Emily Twidale
Address 99974 0
Women's and Children's Department
Hamilton Hospital
Waikato DHB
Pembroke St
Hamilton, 3204
Country 99974 0
New Zealand
Phone 99974 0
+64 273193026
Fax 99974 0
Email 99974 0
Contact person for public queries
Name 99975 0
Dr Emily Twidale
Address 99975 0
Women's and Children's Department
Hamilton Hospital
Waikato DHB
Pembroke St
Hamilton, 3204
Country 99975 0
New Zealand
Phone 99975 0
+64 273193026
Fax 99975 0
Email 99975 0
Contact person for scientific queries
Name 99976 0
Dr Emily Twidale
Address 99976 0
Women's and Children's Department
Hamilton Hospital
Waikato DHB
Pembroke St
Hamilton, 3204
Country 99976 0
New Zealand
Phone 99976 0
+64 273193026
Fax 99976 0
Email 99976 0

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No/undecided IPD sharing reason/comment
Because of the risk of personal identification. This trial will be offered to all women having outpatient hysteroscopies in a small regional centre. The demographic features we capture may be indirectly identifying and therefore the data should be kept private.
What supporting documents are/will be available?
No other documents available
Summary results
No Results