Ultrasound Guided Transversus Abdominis Plane (TAP) Block for Postoperative Analgesia After Laparoscopic Colonic Resection- a Double Blind Randomised Controlled Trial
Summary of Study Design The study will be a double blind randomised controlled trial with
patients undergoing laparoscopic right hemicolectomy or laparoscopic high anterior resection
randomly allocated into two groups, with the study group receiving bilateral TAP blocks
followed by a morphine PCA and the control group receiving local anaesthetic infiltration of
the laparoscopic port sites and specimen extraction site and a morphine PCA.
A double blind design was chosen to eliminate patient and observer bias in reporting of pain
The presence of the control arm will ensure that any difference observed will be due to the
effect of sensory nerve block due to the TAP block than due to the systemic effect of the
injected local anaesthetic.
The null hypothesis will be that there is no difference between the groups in the amount of
morphine consumed by the patients during 48 hours after the operation. We chose this
measurement as an objective but indirect measurement of efficacy of TAP block and pain
relief thus received. Measurement of pain with various scoring methods are reliable only
when concurrent reduction in consumption of pain killers are demonstrated.
Recruitment and randomisation:
All patients meeting the inclusion criteria will receive a patient information leaflet and
an invitation letter to participate in the study during the pre-assessment visit. We aim to
recruit 72 patients (36 patients per group).
Informed consent will be taken by one of the investigators on the morning of the surgery, if
the exclusion criteria are not applicable. Patients will be allotted consecutive participant
numbers starting from one. Patients will be randomly allocated into either the study group
and a control group. Randomisation will occur by using computer generated random numbers.
Group allocation will be kept in a consecutively numbered, opaque, sealed envelope in the
controlled drugs cupboard in theatre-6 anaesthetic room of Churchill hospital.Once patient
has consented, the anaesthetist will open the corresponding numbered envelope and perform
bilateral TAP blocks after induction of general anaesthesia, if the patient is in the study
group the surgeons will infiltrate the port sites with local anaesthetic at the end of the
procedure if the patient is in the control group.
The study group will receive bilateral TAP blocks with 20mls 0.25% bupivacaine on each side
and the skin punctures on either sides will be covered with a small plaster. Patients in the
control group will receive subcutaneous infiltration of the laparoscopic port sites and
specimen extraction site with equivalent amount bupivacaine at the end of the procedure and
small plasters will be stuck on either flanks approximately where the skin punctures for TAP
block will be made.
The assessor of pain scores and morphine doses (Recovery nurse & Colo-rectal house officer)
and the patient will be blinded to group allocation.
Patient: Plasters will be stuck on flanks of all the patients both study and control group
so that patient will not know if they have received TAP block.
Recovery nurse: During handover to recovery the anaesthetist and scrub nurse will not
mention about group allocation.
Colo-rectal house officer: The house officers( Junior Doctors) who will be following up in
the ward will not present in the operating theatre, so they will be blinded
The study duration will be from induction of anaesthesia until the patients are medically
fit for discharge from hospital. No extra visits other than routinely required for the
surgical procedure is expected.
Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Parallel Assignment, Masking: Double Blind (Subject, Outcomes Assessor), Primary Purpose: Treatment
Morphine consumption in the first 48hours after the operation
Total morphine consumption in the first 48 hours after the surgery will be calculated from the drug chart and the Patient controlled analgesia(PCA)pump.
48 hours after the operation
Nicholas Crabtree, MB,ChB, FRCA
Nuffield Department of Anaesthetics, Oxford Radcliffe Hospitals NHS Trust , Oxford
United Kingdom: Research Ethics Committee
Sponsorship review number:113