The distribution and duration of the sensory block after a standard and refined ultrasound guided transversus abdominis plane (TAP) block.

• Register: ANZCTR
• Last refreshed on: 13 January 2020
• Main ID: ACTRN12610000094077
• Date of registration: 27/01/2010
• Prospective Registration: No
• Primary sponsor: Dr Phillip Cowlishaw
• 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.
• Date of first enrolment: 01/01/2010
• Target sample size: 20
• Recruitment status: Recruiting
• URL: https://anzctr.org.au/ACTRN12610000094077.aspx
• Study type: Interventional
• Study design: Purpose: Treatment; Allocation: Randomised controlled trial; Masking: Blinded (masking used);Assignment: Parallel;Type of endpoint: Efficacy;
• Phase: Not Applicable

Countries of recruitment

Australia

Contacts

• Name: Phillip Cowlishaw

• Name: Phillip Cowlishaw

Key inclusion & exclusion criteria

Inclusion criteria: All participants undergoing lower abdominal surgery through a midline incision at the Mater Hospital who are scheduled to receive a TAP block
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

Age minimum: 18 Years
Age maximum: No limit
Gender: Both males and females

Health Condition(s) or Problem(s) studied

Anaesthesiology - Anaesthetics

Pain;
Pain

Intervention(s)

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 inj

Primary Outcome(s)

To assess the duration of the TAP block[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(s)

To compare the analgesic quality and sensory block in participants who have received a standard needling technique compared with the refined needling technique[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]

To assess the distribution of sensory blockade after a TAP block[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 ID(s)

None

Source(s) of Monetary Support

Mater Health Services

Secondary Sponsor(s)

Dr Tim Sampson

Ethics review

Status: Approved
Approval date:
Contact:

Mater Health Services Human Research Ethics Committee