Intraoperative confirmation of ulnar collateral blood flow during radial artery harvesting using the “squirt test”

Hand ischemia is a major concern after radial artery harvesting for coronary revascularization. Although a number of preoperative tests have been described to assess the adequacy of ulnar collateral blood flow, many of them are subjective and unreliable. In addition, the presence of arterial connections between the radial and ulnar systems in the elbow and forearm and variability in forearm angiology imply that assessment of alternative blood supply to the hand can only be made once collateral branches of the radial artery have been divided. We describe a technique for intraoperative assessment of ulnar collateral blood flow after mobilization and division of collateral branches of the radial artery.