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Trial registered on ANZCTR


Registration number
ACTRN12614000343606
Ethics application status
Approved
Date submitted
23/03/2014
Date registered
31/03/2014
Date last updated
17/03/2016
Type of registration
Prospectively registered

Titles & IDs
Public title
A Randomised Trial of the Effectiveness of Different in vitro Models in Teaching Ultrasound Guided Regional Anaesthesia
Scientific title
Novices in ultrasound guided regional anaesthesia will be randomised to receive deliberate practice training on either low fidelity meat model or high fidelity cadaveric model to determine the effectiveness of the 2 different in vitro models in learning technical tasks in ultrasound guided regional anaesthesia.
Secondary ID [1] 284315 0
None
Universal Trial Number (UTN)
U1111-1154-8451
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
education in ultrasound guided regional anaesthesia 291464 0
Condition category
Condition code
Anaesthesiology 291833 291833 0 0
Anaesthetics

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Volunteers who are novices in ultrasound guided regional anaesthesia are randomised to 2 equal groups, called Group M (meat model) and Group C (cadaver model). Group C will be the intervention for this randomised controlled trial.
These models represent in vitro training models currently used for training. Both Groups will receive deliberate practice training and feedback after each attempt (total 30 attempts), delivered by a faculty with expertise in ultrasound guided regional anaesthesia. The feedback involves specific training in ultrasound guidance, needle visibility, transducer movements, and image quality techniques.
Performance of each group is scored at the end of the 30 attempts using a previously published objective assessment tool, testing efficiency, proficiency, and error rates of ultrasound guided regional anaesthesia.
The study will be performed over a single day, with break sessions scheduled to reduce risk of fatigue
Intervention code [1] 289036 0
Other interventions
Comparator / control treatment
low fidelity meat model, composed of a fresh pork phantom with tendons inserted longitudinally to simulate nerves. Will receive the same deliberate practice and feedback over 30 attempts, with the study performed over a single day with scheduled breaks to minimise risk of fatigue
Control group
Active

Outcomes
Primary outcome [1] 291751 0
Time taken (seconds) from insertion of the needle using an in-plane technique (maintaining visualisation of needle shaft and tip) to the 6 o’clock and 12 o’clock positions of the target, and injecting 0.5mls of saline at each position. Two blinded assessors will independently mark each participant.
Timepoint [1] 291751 0
performance of task after 30 practice attempts
Secondary outcome [1] 307410 0
Number of needle passes. Two blinded assessors will independently mark each participant.
Timepoint [1] 307410 0
performance after 30 practice attempts
Secondary outcome [2] 307411 0
Number of errors during performance of task. Two blinded assessors will independently mark each participant.
Timepoint [2] 307411 0
performance after 30 practice attempts
Secondary outcome [3] 307412 0
Image quality score of best sonoanatomical image. Two blinded assessors will independently mark each participant.
Timepoint [3] 307412 0
performance of task after 30 practice attempts

Eligibility
Key inclusion criteria
adults, enrolled in an undergraduate or postgraduate health sciences degree (eg. medicine, nursing, physiotherapy, occupational therapy, medical science).
No previous experience or exposure to ultrasound guided procedures, or training in diagnostic ultrasound
Minimum age
18 Years
Maximum age
No limit
Gender
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
Any previous experience or training in ultrasound

Study design
Purpose of the study
Educational / counselling / training
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
sealed opaque envelopes numbered 1 to 50, 25 each containing either Group M or Group C
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
simple randomisation using a computerised sequence generation
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?


The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Parallel
Other design features
Phase
Not Applicable
Type of endpoint(s)
Efficacy
Statistical methods / analysis
Two sided two sample t tests will be performed for the primary outcome of times taken between the two groups. 2 sample t tests will be performed for baseline and post-training performances within groups, and paired t tests will be performed on secondary outcomes with a more stringent significance of 0.01 to account for multiple comparisons. If data exhibits right skewness then the analyses will be performed on natural logarithm transformed data.

Recruitment
Recruitment status
Completed
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)
NSW
Recruitment hospital [1] 2228 0
Macquarie University Hospital - Macquarie Park
Recruitment postcode(s) [1] 7908 0
2109 - Macquarie University

Funding & Sponsors
Funding source category [1] 288955 0
Charities/Societies/Foundations
Name [1] 288955 0
Australian Society of Anaesthetists
Address [1] 288955 0
PO Box 6278
North Sydney
NSW 2059
Country [1] 288955 0
Australia
Primary sponsor type
University
Name
Australian School of Advanced Medicine, Macquarie University
Address
2 Technology Place
Macquarie University
NSW 2109
Country
Australia
Secondary sponsor category [1] 287634 0
None
Name [1] 287634 0
Address [1] 287634 0
Country [1] 287634 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 290765 0
Macquarie University Human Sciences HREC
Ethics committee address [1] 290765 0
Research Office
Level 3, Research HUB, Building C5C East
Macquarie University
NSW 2109
Ethics committee country [1] 290765 0
Australia
Date submitted for ethics approval [1] 290765 0
30/03/2014
Approval date [1] 290765 0
05/08/2014
Ethics approval number [1] 290765 0

Summary
Brief summary
BACKGROUND
Ultrasound guided regional anaesthesia (UGRA) is a complex component of anaesthesia practice to learn. UGRA has evidence of improved safety, efficacy and is considered standard of care for peripheral nerve blocks.
To safely practice UGRA, procedural accuracy is required when introducing the nerve block needle into the patient and guiding that needle to the target nerve structure under real time ultrasound guidance. This procedural task encompasses several domains of knowledge and manual dexterity skills:
1. Ability to manipulate the ultrasound transducer to visualise and optimise the nerve and surrounding tissue sonoanatomy
2. Ability to plan a needle path trajectory that maintains an in-plane visualisation of the needle shaft and tip from skin surface to deeper structures
3. Motor skill ability to guide the needle under real time visualisation to inject local anaesthesia at positions around the nerve to create a circumferential deposition of injectate (local anaesthesia)
4. Ability to recognise an optimal spread of injectate and to correct the needle position appropriately

Successful performance of UGRA thus requires hand-eye coordination and needle guidance techniques to maximise efficacy while minimising potential complications.

Learning curve patterns of novices performing UGRA in patients has revealed an initial high rate of errors, from a mean of 12.6 errors per block during the first 10 attempts, decreasing to 4.6 errors per block by the end of the 39th attempt. In a study using cadavers, 28 UGRA attempts were required to reach competency as defined by needle visualisation under ultrasound and transducer steadiness. Both studies revealed wide variability in novices' error and success rates. This suggests that UGRA skills are difficult to master and individuals reach proficiency at different times, due to innate psychomotor abilities.
For ethical reasons, initial teaching of these procedural skills has thus focused on in vitro models. It allows repeated practice of high stakes procedural skills without risk of patient harm. It concentrates trainees and trainers in a single learning environment. A curriculum can be devised without distractions of clinical duties as occurs in hospital-based teaching.

The ideal in vitro model should be inexpensive, has similar properties to human tissue both under ultrasound (echogenicity, fascial planes, muscle texture, hyperechoic peripheral nerves, arterial and venous blood vessels that collapse appropriately under pressure, spread of injectate along fascial planes and around nerves, swelling of the nerve sheath if an intraneural injection was performed), as well as tactile feedback of resistance and fascial plane pops when a facet tipped nerve block needle is used.
Commonly used in vitro models include the gelatin model, meat model, and fresh frozen human cadaveric model. None of these satisfy as an ideal model, and all have advantages and disadvantages.
Inexpensive and easily procured models such as gelatin and meat based models are commonly used in teaching, but offer a low fidelity experience of what a trainee would expect when performing UGRA in patients. Anatomical relationships, tactile feedback, appearance of human tissues and fascial planes under ultrasound, and nerve block needle echogenicity are not realistic. In our experience, these models are useful in introducing novices to UGRA but create overconfidence in performance as they do not reflect the clinical reality.
The meat model, usually constructed out of turkey, beef or pork, is relatively inexpensive, easy to construct, and has more similar properties to human tissue in terms of echogenicity and texture. Hydrodissection by injections of simulated local anaesthetic can also be performed. However, meat models do not have realistic human anatomical relationships.
Unlike traditional formalin based cadaveric dissections, fresh frozen human cadavers retain all of the in vivo anatomical relationships and currently represents the highest fidelity model for UGRA training. Nerves, fascial planes, and muscle textures are similar to live patients. Tactile feedback is retained when performing needling manoeuvres. Injection spreads patterns are similar to live patients. Limitation to access include financial cost and scarcity of centres accredited to handle fresh cadavers.

This study will compare the effectiveness of two in vitro models commonly used to teach UGRA: pork meat model, and fresh frozen cadavers. Effectiveness is measured using objective assessment of proficiency in procedural skills before and after exposure to different in vitro models.

RATIONALE FOR PERFORMING THE STUDY
The traditional apprenticeship model of teaching medicine has emphasised clinical exposure and supervised tutelage of procedural skills in our patients. Due to multiple factors including ethical concerns of relatively unskilled trainees performing invasive procedures on patients, reduction in caseload due to safe working hours directives, and reduction of available teaching staff, this apprenticeship model may be inappropriate.

In UGRA, poor needle visualisation and suboptimal sonoanatomical imaging have been identified as the two most common mistakes in novices, which may contribute to patient complications during nerve blocks. Educators are still uncertain as to the best methods of teaching UGRA, including what are the best in vitro models.

In this study, we will compare the effectiveness of 2 commonly used in vitro models. The models range from low fidelity (but low cost, easily accessible) to high fidelity (but high cost, not easily accessible). Each model has been used and reported in literature, but no previous study has compared each model's effectiveness in teaching procedural skills to trainees.

The results of this study will inform us of the value of fresh frozen cadavers in UGRA teaching. We will compare the relative skills of trainees taught with different models using an objective assessment tool. If the hypothesis is confirmed, we would recommend that fresh frozen cadavers be incorporated into regular UGRA teaching.

HYPOTHESIS
That fresh frozen human cadavers, representing a high fidelity simulator of human anatomy, is the most effective in vitro model to teach UGRA technical skills to doctors training in anaesthesia when measured against time taken, error rates, and success rates.

STUDY OBJECTIVES
Primary objective is time taken from insertion of the needle using an in-plane technique (maintaining visualisation of needle shaft and tip) to the 6 o’clock and 12 o’clock positions of the target, and injecting 0.5mls of saline at each position.

Secondary outcomes were selected based on common problems exhibited by novices in UGRA.
1. Number of needle passes
2. Number of errors during performance of task
3. Image quality score of best sonoanatomical image
Trial website
n/a
Trial related presentations / publications
Chuan A et al. Comparison of human cadaveric and meat-based models for teaching ultrasound-guided regional anaesthesia: a randomised controlled trial. In print, Anaesthesia 2016.
Public notes
n/a

Contacts
Principal investigator
Name 47174 0
Dr Alwin Chuan
Address 47174 0
Australian School of Advanced Medicine
2 Technology Place
Macquarie University
North Ryde
NSW 2109
Country 47174 0
Australia
Phone 47174 0
+61 407743668
Fax 47174 0
Email 47174 0
achuan@iinet.net.au
Contact person for public queries
Name 47175 0
Dr Alwin Chuan
Address 47175 0
Australian School of Advanced Medicine
2 Technology Place
Macquarie University
North Ryde
NSW 2109
Country 47175 0
Australia
Phone 47175 0
+61 407743668
Fax 47175 0
Email 47175 0
achuan@iinet.net.au
Contact person for scientific queries
Name 47176 0
Dr Alwin Chuan
Address 47176 0
Australian School of Advanced Medicine
2 Technology Place
Macquarie University
North Ryde
NSW 2109
Country 47176 0
Australia
Phone 47176 0
+61 407743668
Fax 47176 0
Email 47176 0
achuan@iinet.net.au

No information has been provided regarding IPD availability
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary