TAP Block for Gynaecological Laparotomies - a Comparison of Ultrasound-guided Block and Blind Technique
Condition: Laparotomy
Study type: Interventional

Summary: 
      Transversus abdominis plane (TAP) block is an application of local anaesthetic solution into
      the plane between internal oblique and transversus abdominis muscles at the triangle of Petit
      located superiorly to the iliac crests bilaterally. Anterior divisions of segmental spinal
      nerves, which provide innervation to the abdominal wall, run inside this compartment. TAP
      block been shown to provide good postoperative pain relief following surgical laparotomies,
      gynaecological laparotomies, appendicectomies, inguinal hernia repairs and open
      prostatectomies. The goal of this study is to compare the effect of blind and
      ultrasound-guided TAP block on postoperative pain relief and morphine consumption following
      to gynaecological laparotomies. Null research hypothesis for the study is that there is no
      difference between the performance (as defined by morphine consumption and patient
      satisfaction/ pain scores) of the TAP block procedure via 'blind' or ultrasound guided
      techniques for gynaecological laparotomies.
    

Detailed description: 
      Transversus abdominis plane (TAP) block is an application of local anaesthetic solution into
      the plane between internal oblique and transversus abdominis muscles at the triangle of Petit
      located superiorly to the iliac crests bilaterally. Anterior divisions of segmental spinal
      nerves, which provide innervation to the abdominal wall, run inside this compartment. The TAP
      block has been shown to provide good postoperative pain relief following surgical
      laparotomies, gynaecological laparotomies, appendicectomies, inguinal hernia repairs and open
      prostatectomies. It also reduces the post operative morphine consumption seen after such
      procedures. This allows a more comfortable recovery with reduced incidence of nausea and
      vomiting, as well as potentially earlier mobilisation and discharge.

      Currently the technique employed is that first described by Mc Donnell. This involves a blind
      'two pop' technique signifying the needle passing through the two muscle layers. On detection
      of these two pops the local anaesthetic is injected into this plane between the muscle
      layers. It is the anaesthetising of the nerves in this muscle plane that aides post operative
      pain relief for as much as 24 hours. TAP nerve blocks have become common practice due to the
      very low reported complication rate occurring while using the 'blind technique'. Such
      complications are minor in themselves. It is our hope that these complications will be
      further reduced with the use of an ultrasound guided technique. The use of an ultrasound
      machine would allow the direct visualisation of the needles progress through the tissues and
      muscle layers. It would confirm the correct position during infiltration of local anaesthetic
      and prevent inadvertent puncturing of organs or entry to the abdominal space.

      Studies have shown that in other commonly used nerve blocks, the introduction of an
      ultrasound guided technique has improved the efficacy of the nerve block itself. We hope to
      show a similar trend when using an ultrasound guided technique in the insertion of a TAP
      block. Trials are underway comparing different dosage and volume regimes, but to our
      knowledge no other trial is comparing the use of an ultrasound machine to the conventional
      'blind' technique in order to assess pain relief and morphine consumption post operatively.

      Only recently have ultrasound machines become commonplace in anaesthetic departments, and we
      feel this research will show their valuable contribution to patient comfort in this subgroup
      of patients undergoing abdominal gynaecological procedures. We wish to assess whether we can
      achieve better patient satisfaction, less morphine consumption and ultimately shorter
      hospital stay with an ultrasound technique compared to a blind technique.
    

Intervention name(s): Transversus abdominis plane (TAP) block
Intervention type(s): Procedure
Intervention description(s): Application of local anaesthetic solution (LA) levo-bupivacaine (dose 1mg/kg for each side, concentration 2.5 mg/mL) between internal oblique abdominis muscle and transversus abdominis muscle on both sides.
Other intervention name(s): TAP block
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Participant)
Primary purpose: Treatment
Keywords: Transversus abdominis plane; Acute pain service; Ultrasound