Trial Review

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Trial registered on ANZCTR


Registration number
ACTRN12610000094077
Ethics application status
Approved
Date submitted
18/01/2010
Date registered
27/01/2010
Date last updated
11/07/2012
Type of registration
Retrospectively registered

Titles & IDs
Public title
The distribution and duration of the sensory block after a standard and refined ultrasound guided transversus abdominis plane (TAP) block.
Scientific title
A randomised, double blind, pilot study to evaluate the distribution and duration of the sensory block after a standard and refined ultrasound guided transversus abdominis plane (TAP) block.
Secondary ID [1] 1335 0
None
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Pain 256439 0
Condition category
Condition code
Anaesthesiology 256611 256611 0 0
Anaesthetics

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
The aims of the study are to evaluate the duration and distribution of the sensory block after an ultrasound guided TAP block using a standard and refined needling technique. Twenty participants undergoing lower abdominal surgery through lower midline incision will be studied prospectively. Each participant will receive a bilateral TAP block using the refined needling technique on one side of the abdomen and the standard needling technique on the other side. Randomisation will determine which side receives which technique.

The standard technique requires the needle to be inserted medial and parallel to the ultrasound probe. With ultrasound guidance it is directed ‘in plane’ to ensure the tip lies between the internal oblique and transversus abdominis 1-2cm anterior to where the transversus abdominus muscle becomes a fascial extension. To confirm location, 2ml of normal saline can be injected. Once position is satisfactory, 0.5% Ropivacaine is injected in 5ml aliquots with aspiration between injection to a total of 0.75mg/kg. The time required to perform this procedure is 5 to 10 minutes.

The refined technique requires the needle to be inserted more medially compared with the standard technique and directed slightly laterally towards the ultrasound probe. Using ultrasound 'in plane' guidance the needle is positioned in the transversus abdominis plane at its anterior origin and advanced along the plane to ensure at least 5cm of needle is contained within this plane. The tip should still lie 1-2cm anterior to where the transversus abdominus muscle becomes a fascial extension. Hydrodissection with saline may be used to assist needle positioning. Once position is satisfactory, 0.5% Ropivacaine is then injected in 5ml aliquots with aspiration between injection to a total of 0.75mg/kg. Local anaesthetic should form a echolucent band tracking back along the needle separating the internal oblique from the transversus abdominis. The time required to perform this procedure is 10 to 15 minutes.

The refined and standard needling procedures will be performed on the participants at the end of surgery while they are still anaesthetised. They will be only performed once on each participant.


Abdominal sensory mapping (assessment of loss of sensation to ice and light touch) will be performed by a blinded researcher every two hours until full sensation has returned. Assessment of pain on each side of the abdomen will be recorded using visual analogue scores.
Intervention code [1] 255736 0
Treatment: Devices
Comparator / control treatment
Standard TAP block needling technique
Control group
Active

Outcomes
Primary outcome [1] 257504 0
To assess the duration of the TAP block
Timepoint [1] 257504 0
At 1 hour, 3 hours and then 2 hourly post surgery a blinded researcher will assess the participant for sensory changes to ice and light touch on each side of the abdomen. This will be mapped on a anatomical drawing. This will continue until the researcher cannot elicit any sensory changes.
Secondary outcome [1] 262724 0
To compare the analgesic quality and sensory block in participants who have received a standard needling technique compared with the refined needling technique
Timepoint [1] 262724 0
At 1 hour, 3 hours and then 2 hourly post surgery a blinded researcher will assess the participant by:-
1. Asking the participant to complete three visual analogue score (VAS) analgesia scores. One for each side of the abdomen and one to compare each side of the abdomen.
2. Any sensory changes to ice and light touch will be mapped on an anatomical drawing. The researcher will cease assessments when no sensory changes can be ellicited
Secondary outcome [2] 262913 0
To assess the distribution of sensory blockade after a TAP block
Timepoint [2] 262913 0
At 1 hour, 3 hours and then 2 hourly post surgery a blinded researcher will assess the participant for sensory changes to ice and light touch on each side of the abdomen. This will be mapped on a anatomical drawing. This will continue until the researcher cannot elicit any sensory changes.

Eligibility
Key inclusion criteria
All participants undergoing lower abdominal surgery through a midline incision at the Mater Hospital who are scheduled to receive a TAP block
Minimum age
18 Years
Maximum age
No limit
Sex
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
Pre-existing sensory loss/changes on their abdomen
Participants who have received central neuraxial anaesthesia
Contraindication to TAP block (Participants with a body mass index (BMI) >38, local sepsis, coagulation abnormalities – platelets < 80, international normalised ratio (INR)>1.5, activated thromboplastin time (APTT)>1.5, local anaesthetic allergy, abnormal anatomy)
Children and /or young people (age <18)
People with an intellectual or mental impairment
People whose primary language is other than English
Planned surgical infiltration of local anaesthetic or other regional anaesthetic technique

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)
Potential participants will be identified by the research team three-four weeks in advance from the operating lists. A participant information sheet will be given to potential participants in the anaesthetic pre operative assessment clinics or the nursing pre operative assessment clinic. At this time, a brief verbal description of the trial will be given by the anaesthetist or by the nursing supervisor. Participants will attend these clinics as part of their routine pre operative care, usually two-three weeks prior to their operation.

The evening prior to surgery, the potential participants will be contacted by a researcher and a detailed explanation given including the purpose of the trial, the procedure for performing TAP Blocks, risks of TAP Blocks and alternate forms of post-operative analgesia.

Signed consent will be sought by a researcher prior to surgery.

An envelope will be opened at the end of surgery which will allocate the patient to group A or Group B
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Randomisation and Blinding
An independent, non-researcher will produce a computer generated block randomisation table. Participants will be randomised to group A or Group B sequentially according to the randomisation table. These allocations will be concealed in twenty envelopes which will be labelled participants 1 to 20 on the outside.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?



Intervention assignment
Parallel
Other design features
Phase
Not Applicable
Type of endpoint/s
Efficacy
Statistical methods / analysis

Recruitment
Recruitment status
Recruiting
Date of first participant enrolment
Anticipated
1/01/2010
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
20
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)

Funding & Sponsors
Funding source category [1] 256210 0
Hospital
Name [1] 256210 0
Mater Health Services
Country [1] 256210 0
Australia
Primary sponsor type
Individual
Name
Dr Phillip Cowlishaw
Address
Mater Health Services
Raymond Terrace
South Brisbane
QLD 4101
Country
Australia
Secondary sponsor category [1] 251550 0
Individual
Name [1] 251550 0
Dr Tim Sampson
Address [1] 251550 0
Mater Health Services
Raymond Terrace
South Brisbane
QLD 4101
Country [1] 251550 0
Australia

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 258311 0
Mater Health Services Human Research Ethics Committee
Ethics committee address [1] 258311 0
Mater Health Services
Raymond Terrace
South Brisbane
QLD 4101
Ethics committee country [1] 258311 0
Australia
Date submitted for ethics approval [1] 258311 0
Approval date [1] 258311 0
30/10/2009
Ethics approval number [1] 258311 0

Summary
Brief summary
Ultrasound guided Transversus Abominis Plane (TAP) blocks are an effective technique to provide analgesia after lower abdominal surgery. TAP blocks are performed by injecting local anaesthetic around the nerves in the Transversus Abdominis Plane on both sides of the abdomen.

This project seeks to examine the duration and distribution of sensory changes over the patient’s abdomen after bilateral TAP blocks. The study will also compare the standard TAP block technique to a refined technique which may provide superior analgesia.

Each patient in the study, while anaesthetised will receive a standard and a refined TAP block and then will be assessed by a researcher at 1 hour, 3 hours and then 2 hourly until full sensation returns to the abdomen.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 30642 0
Address 30642 0
Country 30642 0
Phone 30642 0
Fax 30642 0
Email 30642 0
Contact person for public queries
Name 13889 0
Phillip Cowlishaw
Address 13889 0
Mater Health Services
Raymond Terrace
Brisbane
Queensland 4101
Country 13889 0
Australia
Phone 13889 0
+61 7 31638646
Fax 13889 0
Email 13889 0
[email protected]
Contact person for scientific queries
Name 4817 0
Phillip Cowlishaw
Address 4817 0
Mater Health Services
Raymond Terrace
Brisbane
Queensland 4101
Country 4817 0
Australia
Phone 4817 0
+61 7 31638646
Fax 4817 0
Email 4817 0
[email protected]

No information has been provided regarding IPD availability


What supporting documents are/will be available?

No Supporting Document Provided



Results publications and other study-related documents

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