Evaluation of needle visibility during insertion of ultrasound guided transversus abdominis plane (TAP) blocks for women undergoing lower abdominal surgery.

All groups will undergo surgery under general anaesthesia. The anaesthetic technique will not be stipulated. At the end of surgery, whilst the patient is still asleep, bilateral TAP blocks will be inserted by the anaesthetist in theatre. Using an echogenic needle for one side and a non-echogenic needle for the other side. Real-time ultrasound guidance will be used to site the needle tip below the fascia with the TAP. Which needle is used first will be determined by the randomisation process. The time taken to perform the TAP block on each side will be recorded from the time the needle goes through the skin until the time the injection of local anaesthetic is complete. The dose of local anaesthetic used will be 1.5mg/kg of ropivacaine diluted to a total volume of 20ml used each side. The maximal total dose will be 200mg ropivacaine. A 60 sec retrospective video clip of the ultrasound image will be recorded once 10mls of local anaesthetic has been injected.