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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Retrospectively registered

Titles & IDs
Public title
Ultrasound guided transversus abdominis plane (TAP) block for analgesia after caesarean surgery.
Scientific title
In women having caesarean sections, do transversus abdominis plane blocks, when compared to placebo, reduce morphine requirements?
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Postoperative acute pain 3708 0
Condition category
Condition code
Anaesthesiology 3875 3875 0 0
Pain management

Study type
Description of intervention(s) / exposure
Ultrasound guided transversus abdominis plane (TAP) block with local anaesthetic. At the end of the caesarean section, a TAP block will be performed with either local anaesthetic or placebo.

TAP block technique
Ultrasound – 38mm linear array probe 13-6MHz
22G 150mm Stimuplex needle
Study drug – 40ml of 0.5% ropivacaine / saline
Betadine antiseptic preparation for skin preparation
Pulse oximetry to measure heart rate
Availability of full monitoring and resuscitation equipment

Identification of landmarks
Ultrasound positioned in the mid axillary line in the axial plane half way between the iliac crest and the costal margin.
Structures to be identified: subcutaneous fat, external oblique muscle, internal oblique muscle, transversus abdominis muscle, peritoneum and intraperitoneal structures. As a means of confirmation, the transversus abdominis tends to be darker and less echogenic.
If these are not readily identified, the probe may be moved posteriorly to identify the latissimus dorsi muscle which is external to the fascial extension of these muscles. The probe may also be moved anteriorly to the rectus sheath and the fascial planes followed back out laterally. The final position of the probe is to be no further anterior than the anterior axillary line. Oblique angulation may assist with identifying the planes.
Landmarks are to be classified as 'unsatisfactory' if any of 1. external oblique, 2. internal oblique, 3. transversus abdominis, or 4. intraperitoneal structures cannot be identified posterior to the anterior axillary line. The block may still be performed if the investigator is satisfied that the transversus abdominis muscle can be differentiated. Views will be considered ‘excellent’ if quadratus lumborum can be seen in addition to the above four structures.
If landmark identification is impossible, the block will not be performed.

Needle technique
The needle is inserted 'in plane' and directed to lie between the internal oblique and transversus abdominis under real time ultrasound guidance.
To confirm location, 2ml of local anaesthetic can be injected.
Once position is satisfactory, local anaesthetic is then injected in 5ml aliquots with aspiration between injection to a total of 20ml each side. Appropriate placement will be judged as production of an echolucent plane between the two muscles. Visible separation of muscle bundles of the internal oblique considered superficial placement. Separation of muscle bundles of the transversus abdominis indicates deep placement. Superficial or deep placement requires the needle to be repositioned.

Intervention drug
The active treatment arm will receive 20ml of 0.5% ropivacaine on each side (total 200mg ropivacaine). The placebo arm will receive 20ml saline on each side. The local anaesthetic duration of action is expected to be between 12 and 24 hours.
Intervention code [1] 3420 0
Treatment: Drugs
Comparator / control treatment
Ultrasound guided transversus abdominis plane block with inactive placebo (saline) at the end of the caesarean section.
Control group

Primary outcome [1] 4778 0
Morphine dose from patient controlled analgesia
Timepoint [1] 4778 0
6, 12, 18 and 24 hours
Secondary outcome [1] 8072 0
Visual analogue pain score
Timepoint [1] 8072 0
24 hours
Secondary outcome [2] 8073 0
Highest sedation score recorded
Timepoint [2] 8073 0
24 hours
Secondary outcome [3] 8074 0
Number of doses of antiemetics
Timepoint [3] 8074 0
24 hours
Secondary outcome [4] 8075 0
Self reported nausea and vomiting
Timepoint [4] 8075 0
24 hours
Secondary outcome [5] 8076 0
Self reported pruritus
Timepoint [5] 8076 0
24 hours

Key inclusion criteria
Patients having elective caesarean sections under spinal or combined spinal epidural anaesthesia.
Minimum age
18 Years
Maximum age
No limit
Can healthy volunteers participate?
Key exclusion criteria
Conditions associated with opioid tolerance: regular opioid analgesia use in the last three months, previous intravenous (IV) drug use

Transversus abdominis plane block technically difficult to perform: obesity (body mass index (BMI) > 35)

Contraindication to TAPB: local sepsis, local anaesthetic allergy, abnormal anatomy preventing spread of local anaesthetic (for example nephrectomy scars)

Contraindications to non-steroidal anti-inflammatory drugs: renal dysfunction, peptic ulcer disease, aspirin sensitive asthma, pregnancy induced hypertension/pre-eclampsia

Contraindications to neuraxial anaesthesia

Planned general anaesthesia

Risk of local anaesthetic toxicity: booking-in weight less than 50kg. Other local anaesthetic administration.

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
All patients undergoing elective caesarean section at the Mater Mothers' Public and Private Hospital are eligible.

When patients are booked for elective caesarean section in the obstetric clinics, they receive the information sheet about this research.

An opportunity is given to all patients to discuss the study before the day of surgery with an anaesthetist. This occurs either at the anaesthetic clinic or by telephone interview. Patients are then be approached on the day of surgery in the admissions area by the investigator.

Allocation to placebo or treatment group is by sequentially numbered syringes filled with either placebo or local anaesthetic by the pharmacy.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Random order generation is by block randomisation using a randomisation table.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?

Intervention assignment
Other design features
Phase 4
Type of endpoint(s)
Statistical methods / analysis

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)

Funding & Sponsors
Funding source category [1] 3888 0
Commercial sector/Industry
Name [1] 3888 0
Address [1] 3888 0
5 Alma Road
North Ryde 2113
Country [1] 3888 0
Funding source category [2] 3889 0
Name [2] 3889 0
Mater Misericordiae Health Services Brisbane Ltd
Address [2] 3889 0
Raymond Terrace
South Brisbane Qld 4101
Country [2] 3889 0
Primary sponsor type
Mater Misericordiae Health Services Brisbane Ltd
Raymond Terrace
South Brisbane Qld 4101
Secondary sponsor category [1] 3571 0
Name [1] 3571 0
Address [1] 3571 0
Country [1] 3571 0

Ethics approval
Ethics application status
Ethics committee name [1] 5937 0
Mater Health Services Human Research Ethics Committee
Ethics committee address [1] 5937 0
Rm 235
Level 2 Aubigny Place
Raymond Terrace
South Brisbane QLD 4101
Ethics committee country [1] 5937 0
Date submitted for ethics approval [1] 5937 0
Approval date [1] 5937 0
Ethics approval number [1] 5937 0

Brief summary
The transversus abdominis plane (TAP) block is a local anaesthetic technique that has been developed in recent years for pain relief after abdominal surgey. It has been shown to work after caesarean delivery when performed by skilled operators. We aim to test an ultrasound guided approach to this block for pain relief after caesarean section. Women having elective caesarean sections will be randomly allocated to receive an ultrasound guided TAP block with local anaesthetic or placebo in addition to standard pain relief including morphine. We hope to find women who receive the local anaesthetic have better pain relief, need less morphine and have fewer side effects from morphine after caesarean section.
Trial website
Trial related presentations / publications
Presented at the Australia and New Zealand College of Anaesthetists Annual Scientific Meeting in Cairns 2009.

Ultrasound-guided transversus abdominis plane block for analgesia after Caesarean delivery
D. Belavy; P. J. Cowlishaw; M. Howes; F. Phillips
British Journal of Anaesthesia 2009; doi: 10.1093/bja/aep235
Public notes

Principal investigator
Name 28945 0
Address 28945 0
Country 28945 0
Phone 28945 0
Fax 28945 0
Email 28945 0
Contact person for public queries
Name 12102 0
Dr Phillip Cowlishaw
Address 12102 0
Mater Misericordiae Health Services Brisbane Ltd
Raymond Terrace
South Brisbane Qld 4101
Country 12102 0
Phone 12102 0
07 31638646
Fax 12102 0
Email 12102 0
Contact person for scientific queries
Name 3030 0
Dr Phillip Cowlishaw
Address 3030 0
Mater Misericordiae Health Services Brisbane Ltd
Raymond Terrace
South Brisbane Qld 4101
Country 3030 0
Phone 3030 0
07 31638646
Fax 3030 0
Email 3030 0

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