Unable to recruit

The purpose of this study is to investigate what effect a local anesthetic nerve block of the arm in patients with end stage renal failure has upon blood flow in the skin of the arm.

Aim

To quantify the degree of sympathetic blockade in the upper limb in patients with end stage renal failure produced during a regional anaesthetic technique, using laser Doppler flowmetry.

Hypothesis

Regional anaesthesia of the upper limb results in blockade of motor and sensory nerves, providing surgical and post-operative analgesia. Sympathetic nerves are also blocked resulting in local vasodilatation. This may be of benefit in surgery where enhanced blood flow is beneficial such as arterio-venous fistula creation. The degree and duration of sympathetic blockade produced by regional blocks however, has never been quantified. This study aims to quantify sympathetic blockade by measuring the changes in skin blood flow and skin temperature after placement of a brachial plexus block.

Inclusion Criteria:

• Patients with end stage renal failure
• Over 18 years of age
• Written consent obtained
• Due to undergo surgery for forearm fistula creation under a regional block

Exclusion Criteria:

• Smokers
• Damaged skin on the arm
• Circulatory disorders such as Raynaud's disease, systemic sclerosis, sickle cell trait or disease
• Current use of beta blockers
• undergoing haemodialysis for more than 12 months

Patients with end stage renal failure who are due to have a forearm fistula created