In atherosclerotic patients undergoing kidney transplantation, arterial cannulation is commonly performed for continuous monitoring of systemic blood pressure and intermittent assessment of arterial blood gases. The radial artery is the preferred artery, because of its well-documented low complication rate and easy access, but, radial artery cannulation is may associated with complications. Atherosclerosis is a systemic phenomenon, and structural changes attributable to atherosclerosis, such as luminal narrowing, intimal hyperplasia, and reduction in distensibility occur frequently throughout the arterial tree. Especially in patients with diabetes mellitus (DM), the radial artery is prone to atherosclerosis and perhaps calcification. In a recent study, it was found that the radial artery flow was decreased immediately after cannulation, but recovered to its pre-cannulation value after 5min, whereas a compensatory increase of blood flow in the ulnar artery occured immediately after cannulation, persisting until 5 min. This study enrolled the patients of ASA physical status 1-2. In the patients scheduled for elective kidney transplantation, this compensatory increase of blood flow in the ulnar artery may not be occurred, because of atherosclerosis, particularly in patients with DM. In our study, we found whether there is appropriate compensatory increase of blood flow in the ulnar artery after the radial artery cannulation in two groups, patients with DM (group DM) or without DM (group nonDM), both undergoing elective kidney transplantation.

Inclusion Criteria:

• age > 20yrs undergoing kidney transplantation
• ASA physical status ≥ 3
• patients with DM (DM group), patients without DM (nonDM group)

Exclusion Criteria:

• coagulopathy
• inflammation or infection at the puncture site for cannulation
• a positive result on the modified Allen's test
• the cannulation failed twice
• Acute renal allograft rejection