CONCENTRATION AND ED50

• Research type

  Research Study

• Full title

  Does concentration affect the ED50 of bupivacaine for supraclavicular brachial plxus block?

• IRAS ID

  7065

• Contact name

  Pawan K Gupta

• Sponsor organisation

  University of Leeds

• Eudract number

  2008-002335-32

• ISRCTN Number

  n/a

• Research summary

  The local anaesthetic for upper arm operations involves the injection of local anaesthetic around the nerves passing into your arm behind the collar bone. The injection makes the arm and hand go numb for a few hours, after which the sensations and movements return to normal. The medical term for this type of local anaesthetic is “brachial plexus block”. Until recently, anaesthetists have not had the technology to see exactly where the local anaesthetic was going and so they have used large doses of the local anaesthetic to make sure the block had the best chance of working. We now have ultrasound (scanning) machines that let us see precisely where the injection is going. We believe this will allow us to use smaller doses of local anaesthetic agents with less risk of complications. Until now there is no consensus about the optimal volume and the strength of bupivacaine for the supraclavicular block. The purpose of this research study is to find out if it is better to use larger volumes of lower strength or smaller volumes of higher strength local anaesthetic for brachial plexus block. Up to 40 patients will be required to answer the research question based on the Dixons up and down sequential allocation methodology. The patients will be randomly allocated in three groups and will receive one of the three strengths of bupivacaine i.e. 0.25%, 0.375% and 0.5%. The performer and assessor of the block will be blinded to the strength and volume of bupivacaine used for the injection making the study double blind. At the end of the trial the mean effective dose will be calculated and compared in the three groups. The study is powered 80% to detect a difference in the doses of more than 24 mg in the three groups.

• REC name

  Yorkshire & The Humber - Leeds East Research Ethics Committee

• REC reference

  08/H1306/131

• Date of REC Opinion

  28 Nov 2008

• REC opinion

  Further Information Favourable Opinion