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Trial registered on ANZCTR


Registration number
ACTRN12614000076673
Ethics application status
Approved
Date submitted
12/11/2013
Date registered
22/01/2014
Date last updated
22/01/2014
Type of registration
Retrospectively registered

Titles & IDs
Public title
Ultrasound-Assisted Neuraxial Anaesthesia for Caesarean Section
Scientific title
A study on the efficacy and effectiveness of ultrasound-assisted neuraxial anaesthesia versus palpation-assisted neuraxial anaesthesia for elective Caesarean section in terms of needle redirections and skin reinsertions.
Secondary ID [1] 283578 0
Nil
Universal Trial Number (UTN)
Trial acronym
Neuraxial Ultrasound for Maternal Backs (NUMB)
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Difficult neuraxial anaesthesia for elective Caesarean section
290481 0
Condition category
Condition code
Anaesthesiology 290873 290873 0 0
Anaesthetics
Reproductive Health and Childbirth 291310 291310 0 0
Childbirth and postnatal care

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Ultrasound-assisted neuraxial anaesthesia is the intervention examined in this study. A pre-procedure lumbar neuraxial ultrasound is performed to identify the "best" lumbar intervertebral space for the performance of a combined spinal-epidural anaesthetic. Pen ink markings are placed on the patient's skin to identify the appropriate needle insertion point. The procedure takes 3-5 minutes.
Intervention code [1] 288266 0
Treatment: Other
Comparator / control treatment
Palpation-assisted neuraxial anaesthesia is the accepted standard of care. The patient's's iliac crests and lumbar spinous processes are palpated to determine the "best" lumbar intervertebral space for the performance of a combined spinal-epidural anaesthetic. Pen ink markings are placed on the patient's skin to identify the appropriate needle insertion point. The procedure takes 1 minute.
Control group
Active

Outcomes
Primary outcome [1] 290866 0
Epidural needle redirection
Timepoint [1] 290866 0
Monitored during the performance of a combined spinal-epidural anaesthetic prior to an elective Caesarean section
Primary outcome [2] 291236 0
Skin reinsertions (defined as a withdrawal from the skin/subcutaneous tissue and reinsertion of the needle at the same or different intervertebral level)
Timepoint [2] 291236 0
Monitored during the performance of a combined spinal-epidural anaesthetic prior to an elective Caesarean section
Secondary outcome [1] 305498 0
Efficacy of neuraxial anaesthetic blockade level of spinal block measured by sensation to ice & pain, need for epidural top-up during the procedure and conversion to general anaesthetic due to patient discomfort.
Timepoint [1] 305498 0
Duration of operative procedure
Secondary outcome [2] 306303 0
Late complications of neuraxial anaesthesia including post-dural puncture headache, nerve injury and epidural abscess/haematoma
Timepoint [2] 306303 0
Two weeks post-operatively

Eligibility
Key inclusion criteria
Full-term or post-term pregnancy (>37 weeks)
Elective Caesarean section
Nil contraindications for neuraxial anaesthesia
Minimum age
18 Years
Maximum age
No limit
Gender
Females
Can healthy volunteers participate?
Yes
Key exclusion criteria
Pre-term pregnancy (<37weeks pregnant)
Contraindications to neuraxial anaesthesia

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Consecutive patients scheduled for elective LSCS who are deemed appropriate to receive a neuraxial anaesthetic and who do not meet exclusion criteria will be invited to participate in this study during an outpatient anaesthetic pre-admission consultation.

All patients scheduled for an elective lower segment Caesarean section will be reviewed in an outpatient pre-anaesthetic assessment clinic. During this consultation, an anaesthetist will determine their suitability for a combined spinal-epidural anaesthetic for the LSCS. If it is appropriate according to the inclusion/exclusion criteria of the study, the patient will be recruited at this time.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Prior to the commencement of the clinical phase of the trial, 216 envelopes (same size and colour) will be purchased. Two-hundred-and-sixteen cards (same size and colour) will be printed with “Palpation” (108 cards) or Ultrasound (108 cards). One card will be inserted into each envelope and the envelope will be sealed. The envelopes (containing the cards) will be shuffled and stored in a non-see-through box. The operator on the day of the procedure will randomly select a card from the box and give it to the researched performing the ultrasound.
* "Palpation" means the patient is randomised to the palpation-assisted group.
* "Ultrasound" means the patient is randomised to the ultrasound-assisted group.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s


Intervention assignment
Parallel
Other design features
Phase
Phase 3
Type of endpoint(s)
Safety/efficacy
Statistical methods / analysis
There is a paucity of published data examining the efficacy of ultrasound-assisted versus palpation-assisted neuraxial anaesthesia for elective Caesarean section surgery. The sample size was determined using published data from two studies.

Study 1:
Grau T, Leipold RW, Conradi R, Martin E, Motsch J. Ultrasound imaging facilitates localization of the epidural space during combined spinal and epidural anesthesia. Regional Anesthesia and Pain Medicine 2001; 26:64-67.

Eighty parturients scheduled for Caesarean delivery were randomized into 2 equal groups:
* 40 patients underwent CSE without ultrasound imaging – Control Group
* 40 patients underwent CSE after ultrasound imaging – Ultrasound Group


Results:
* Puncture attempts mean was 2.075 (SD =0.829) in the Control Group and in the Ultrasound Group 1.275 (SD=0.506), giving a pooled standard deviation of 0.686.
* Using a 5% level of significance and 80% power, 61 patients will be required to see a difference of 0.5.

Thus, to demonstrate the benefit of ultrasound-assisted versus palpation-assisted neuraxial anaesthesia in the obstetric population undergoing elective Caesarean section, a sample size of 61 would be required.

This study also aims to identify the subgroup of the obstetric patient at higher risk of difficult neuraxial anaesthetic performance. The following study examined the difference between ultrasound-assisted and palpation-assisted neuraxial anaesthesia in obstetric patients with presumed difficult neuraxial anaesthesia performance:

Study 2:
Grau T, Leipold RW, Conradi R, Martin E. Ultrasound control for presumed dif?cult epidural
Puncture. Acta Anaesthesiologica Scandinavica 2001; 45: 766–771

72 parturients with abnormal anatomical conditions who were scheduled for epidural anaesthesia. They were randomised into two equal groups:
* 36 patients underwent CSE without ultrasound imaging – Control Group
* 36 patients underwent CSE after ultrasound imaging – Ultrasound Group

Results
* Mean puncture attempts for the Ultrasound Group was 1.5 (SD =0.9).
* Mean puncture attempts for the Control Group was 2.6 (SD = 1.4).

The population examined in our study will include both presumed easy and difficult patients. Based on clinical practice, patients with difficult to palpate anatomical landmarks are at risk of more difficult neuraxial anaesthesia performance. There is no data available on the incidence of difficult anatomical landmarks in the obstetric (or non-obstetric) population. However, palpation difficulty is closely related to body mass index (BMI). Data from the Royal Brisbane & Women’s Hospital demonstrates that approximately 30% of obstetric patients are severely obese (BMI >35). This puts them at greater risk of difficult palpation and neuraxial anaesthetic performance.

Thus, but comparing the needle puncture attempt data in the easy and difficult populations, the study can be powered to demonstrate a significant difference in these populations based on a 30% incidence of presumed difficult neuraxial performance.

In Study 1 (Easy population) the Ultrasound Group mean was 1.275 (SD=0.506). In Study 2 (Difficult population) the Ultrasound Group mean was 1.5 (SD = 0.9), giving a pooled standard deviation of 0.72. We expect there to be approximately 2.3 more patients in the Easy Ultrasound Group. Using a 5% level of significance and 80% power, 215 patients will be required to see a difference of 0.3 between groups

Recruitment
Recruitment status
Recruiting
Date of first participant enrolment
Anticipated
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
QLD
Recruitment hospital [1] 1682 0
Royal Brisbane & Womens Hospital - Herston
Recruitment postcode(s) [1] 7556 0
4006 - Herston

Funding & Sponsors
Funding source category [1] 288255 0
Self funded/Unfunded
Name [1] 288255 0
Address [1] 288255 0
Country [1] 288255 0
Primary sponsor type
Hospital
Name
Queensland Health
Address
Royal Brisbane & Women's Hospital
Butterfield Street
Herston 4006 QLD
Country
Australia
Secondary sponsor category [1] 286972 0
None
Name [1] 286972 0
Address [1] 286972 0
Country [1] 286972 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 290156 0
Royal Brisbane & Women’s Hospital Human Research Ethics Committee - Registration No: EC00172
Ethics committee address [1] 290156 0
University of Queensland Centre for Clinical Research (UQCCR), Level 4 - Building 71/918 RBWH
Herston Rd
Herston QLD 4006
Ethics committee country [1] 290156 0
Australia
Date submitted for ethics approval [1] 290156 0
24/09/2012
Approval date [1] 290156 0
11/03/2013
Ethics approval number [1] 290156 0
HREC/12/QRBW/438

Summary
Brief summary
Neuraxial anaesthesia (spinal, epidural or combined spinal-epidural anaesthesia) is the gold standard technique for elective lower segment Caesarean section (LSCS) surgery. The traditional and accepted method of performing this anaesthetic procedure involves palpation of the patient’s spinous processes and iliac crests to identify the midline and intervertebral space to appropriately insert the needle and deliver the anaesthetic. The needle is then inserted through the skin, subcutaneous fat and ligaments until the epidural and spinal space is reached. Difficulties can be encountered during this procedure due to the misidentification of the appropriate level of insertion and midline of the spine and needle contact with vertebrae, nerves and blood vessels.
Ultrasound images can help identify structures beneath the skin including bone, ligament anf muscle. This study aims to:
* determine the accuracy of palpation-based identification of intervertebral level and midline of the spine compared with ultrasound,
* assess the efficacy of ultrasound-assisted versus palpation-assisted neuraxial anaesthesia and identify the obstetric population, and
* identify the obstetric population at higher risk of difficult neuraxial insertion.

Full-term pregnant (>37 weeks gestation, adult patients undergoing elective LSCS surgery who are deemed appropriate to receive a neuraxial anaesthesia will be invited to participate in the study. Patients recruited to the study will be randomised to either the palpation-assisted (control) or ultrasound-assisted (intervention) group. Prior to the performance of a combined spinal-epidural anaesthetic, an anaesthetist will identify and mark the midline and “best” lumbar intervertebral space by palpating the patients hip bones and spine. An investigator will then perform an ultrasound of the patient’s lumbar spine to identify and mark the midline “best” intervertebral space.
In the control group, the palpation-identified mark will be used as the needle insertion point. In the intervention group, the ultrasound-identified mark will be used as the needle insertion point. The combined spinal-epidural anaesthetic will be performed using the same standard technique in both groups.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 44242 0
Dr Ben Crooke
Address 44242 0
Department of Anaesthesia & Perioperative Medicine
Royal Brisbane & Women's Hospital
Butterfield Street
Herston QLD 4006
Country 44242 0
Australia
Phone 44242 0
+61 7 3646 8111
Fax 44242 0
Email 44242 0
bencrooke@hotmail.com
Contact person for public queries
Name 44243 0
Dr Ben Crooke
Address 44243 0
Department of Anaesthesia & Perioperative Medicine
Royal Brisbane & Women's Hospital
Butterfield Street
Herston QLD 4006
Country 44243 0
Australia
Phone 44243 0
+61 7 3646 8111
Fax 44243 0
Email 44243 0
bencrooke@hotmail.com
Contact person for scientific queries
Name 44244 0
Dr Ben Crooke
Address 44244 0
Department of Anaesthesia & Perioperative Medicine
Royal Brisbane & Women's Hospital
Butterfield Street
Herston QLD 4006
Country 44244 0
Australia
Phone 44244 0
+61 7 3646 8111
Fax 44244 0
Email 44244 0
bencrooke@hotmail.com

No information has been provided regarding IPD availability
Summary results
No Results