Is ultrasound guided TAP block effective compared to open internal TAP block following abdominal hysterectomy.

• Study setting - Study will be conducted at ward 05, teaching hospital Kandy, Sri Lanka

• Randomization - Block randomization will be carried out following making of computer generated random numbers. This is a three arm study, two treatment arms and one placebo arm. 2 patients (m) per each treatment/placebo group will be allocated within each block of size 6 (3m). There are 11(B) blocks with a total sample size of 66(N= 3mB= 3X2X11). Block of size 6 is expected to collect over 1 week within 1-3 clinic dates.

• Allocation concealment - the interventions concealed by using sealed envelopes.

• Intervention - One arm of study will receive ultrasound guided TAP block immediately following closure of the skin before recovery of patients following skin preparation using betadine. Other arm will receive internal TAP block before closing of the rectus sheath. For both types of TAP blocks we will use a 20 ml syringe with 18G needle and as the anaesthetic agent we will use 20 ml 0.25% bupivacaine for each side followed by a re-aspiration technique to prevent vascular injury and then the bupivacaine will be injected slowly into the appropriate plane.

• Control - All 3 arms will be injected with pethidine 50-75 mg as a single dose immediately following operation (according to the body weight).

• Rescue analgesia will be offered to all participants. Simple analgesics like paracetamol and NSAIDS will be offered to all participant freely on demand and those data also will be documented in data collection form.

• Management of complications- Complications of TAP block include toxicity to the local anesthetic agent and accidental intravascular injection of the anesthetic agent. Safety monitoring will be done intraoperative and up to one year post operatively by both the surgical and anaesthetic team. All patients will be followed up for the occurrence of above mentioned complications by the adverse effect monitoring committee. Study related surgical injuries will be treated by the attending gynaecological team with vascular surgical support Intraoperative and post-operative drug related complications will be managed by the anaesthetic team.

9- Blinding- This is a double blinded study. Randomization will be done by a clinic nurse. She will recruit 6 patients, 2 per each arm, whom decided for abdominal hysterectomy per each clinic day by block randomization using sealed envelopes. Interventions will be done by a SHO/Registrar of gynaecology and MO/ Registrar of anesthesiology. Primary investigator will not take part in interventions, closure of abdomen and final analysis. Demonstrator of the department will be appointed as outcome assessor as well as data analyser. One arm of study of 22 patients will receive ultrasound guided TAP block immediately following closure of the skin before recovery of patients. There won’t be any external marks in all three arms of the study and therefore patients and the primary investigator will be blinded until end of the data collection.

patients who are scheduled and admitted for abdominal hysterectomy 1. via supra pubic transverse incision 2. aged between 40-60 3. American society of anesthesiology physical status classification system grade I-II which includes normal healthy patients, patients with mild systemic diseases like well controlled hypertension, diabetes and mild lung diseases.

1. history of drug allergy to local anesthetic agents
2. local skin abnormalities at the site of introducing the TAP block like burned skin, local infection and inflammatory conditions
3. stage 3-4 endometriosis
4. pelvic inflammatory diseases
5. malignant conditions
6. patients who have diabetes