Should we stop TAP blocks?

by Dr Beh

• Prospective blinded study

• To evaluate with US the placement of the

needle tip and LA during TAP blocks using

landmark-based ‘double pop’ technique

TAP blocks

• One of the techniques of abdominal wall nerve blocks

• Abdominal wall nerve blocks have been used in anaesthesia for surgery involving the anterior abdominal wall for several decades.

Rafi AN. Abdominal field block: a new approach via the lumbar triangle. Anaesthesia 2001; 56: 1024–6

1980s – A technique involving multiple injections of local anaesthetic in the abdominal wall was used

History

Atkinson R, Rushman G, Lee J. A synopsis of anaesthesia, 10th ed.Bristol: Wright, 1987: 637-640.

Blind landmark - lumbar triangle of Petit

1st pop

2nd pop

blunt needle make the loss of resistance more

appreciable

20 – 30ml LA (any %) This block relies on LA

spread rather than concentration

TAP blocks

• Provide excellent intra-op & post-op

analgesia, decrease opioid requirement,

allow patients to breathe and cough

more comfortably, and facilitate early

mobilization & discharge

TAP blocks

TAP blocks

• Is particularly useful for cases when an epidural is contraindicated or refused

• Can be performed unilaterally (e.g. appendicectomy), or bilaterally when the incision crosses the midline (e.g. Pfannenstiel)

• Single injection or catheter

• Rescue analgesia

TAP blocks

 Any surgery involves lower abdominal wall

bowel surgery

appendicectomy

caesarean section

hernia repair

umbilical surgery

gynaecological surgery

TAP block - Indications

Concern regarding blind technique

• Accuracy of placement of needle & LA

• Potential damage to adjacent structure

block failure

intravascular injection

injection into peritoneal cavity, with

associated risks of damage to bowel

and other abdominal viscera

TAP block - Complications

Liver puncture

Colonic puncture

TAP block - Complications

Methodshospital ethic committee

written informed consent

Enrolment: 60 adult patients undergoing elective abdominal surgery

Exclusion criteria: infection at the proposed site of injection, coagulation

disorders, allergy to bupivacaine, pregnancy, BMI > 35 & planned postoperative ICU care admission

Methods

All patients had standard monitoring & IV induction of GA

Before placement of block, the area was prepared with chlorhexidine

An initial US scan of the area was performed by an experienced anaesthetic

ultrasonographer

SonoSite 6 – 13 MHz linear probe (sterile sheath)

All TAP blocks were performed bilaterally by one of the six investigators

“Double pop” landmark technique(mid point of the iliac crest & the costal margin in

the mid-axillary line)

Blunt needle Plexufix 22g

(3 consultant anaesthetist & 3 anaesthetist in training)Each of whom had performed a minimum of 50

landmark based TAP block

Methods

After careful aspiration, 20ml of bupivacaine 0.25% was injected bilaterally

under real-time ultrasound imaging (out of plane technique)

To detect the position of needle & spread of LAs

Methods

The ultrasonographer recorded

Images of pre – and post – injection of LA

subcutaneous tissue, external oblique muscle, plane between the external and internal oblique muscle, internal oblique muscle, TAP, transversus abdominis muscle, peritoneum

Methods

Anatomical site of injection

the anaesthetist performing the block was blinded to the ultrasound image

Post op pain scores were not assessed

Methods

If the needle was in the peritoneum, the anaesthetist performing the block was

alerted by the ultrasonographer and the procedure was repeated

Logistic regression analysis

• to explore the influence of patient age, sex,

BMI, presence of stoma, and the level of

experience of the anaesthetist performing

the block (consultant vs trainee) on the

likelihood of correct placement of the

needle tip and local anaesthetic and the

likelihood of peritoneal placement.

Statistical analysis

Mann-Whitney & Fisher’s exact test

• data analysis

Statistical analysis

Logistic regression analysis

• to determine both patient and operator

factors contributing to inaccurate needle

placement

Results

Study was terminated early due to unacceptable high level of peritoneal

needle placements

Results

17 (23.6%)

13 (18%)

Results 72 injections

32 40

15 VS 2 13

The only factor that predicted peritoneal injection was age after

adjusting for training (consultant or not).

(P = 0.04), (OR = 1.13), 95% confidence interval (1.01, 1.26)

Results

Patient BMI – no effect on successful or peritoneal placement of the needle tip. BMI and thickness of muscle layers or

peritoneal depth - no relationshipNo block-related complications were

noted.

Discussion

The placement of the needle tip and LA using the standard landmark-based approach to the TAP block is

inaccurate

The incidence of peritoneal placement

is unacceptably high

All trainees involved in the trial had performed > 50 blocks each

Discussion

33 % peritonal injection rate

Solution

Discussion

Cost price

RM 35 / set

Polymedic RM 38 / set

Stimuplex RM 28 / set• Courtesy from Mr Asnan

Cost price

RM 50 / set

Contiplex Tuohy RM 121 / set

Locoplex

RM 25 / ampRopi 0.75%RM 14.50 / ampChirocaine 0.5%RM 8.20 / vialMarcaine 0.5%

• Courtesy from Ching Ching, pharmacist Hospital Selayang 2010

DRUGS PRICE (RM)T. PCM 500mg 0.03 per tablet

Supp PCM 125mg 0.20 per suppSupp PCM 250mg 0.20 per supp

Syrup PCM 120mg/5ml (60ml) 1.77 per bottleAspirin 300mg solutablet 0.07 per tablet

Diclofenac injection 75mg/3ml 0.79 per vialDiclofenac acid gel 20g (Voren) 1.50 per tubeDiclofenac sodium 25mg supp 0.57 per supp

Diclofenac sodium 50mg tablet 0.03 per tabletMeloxicam 7.5mg tablet 0.11 per tabletIbuprofen 200mg tablet 0.03 per tablet

Ibuprofen syrup 100mg/5ml (60ml) 1.55 per bottleKetoprofen 2.5% gel 30g 4.40 per tubeKetoprofen 30mg plaster 0.60 per pieceNaproxen tablet 250mg 0.07 per tablet

Mefenamic acid 250mg capsule 0.04 per capsuleCelecoxib 200mg capsule 1.70 per capsuleEtoricoxib 120mg tablet 3.32 per tabletEtoricoxib 90mg tablet 1.87 per tabletTramadol 50mg capsule 0.07 per capsule

Tramadol HCL 50mg/ml injection 0.95 per vial

Cost price