The snuffbox technique: A reliable color Doppler method to assess hand circulation

Objective: Although the Allen test is crude and subjective, an objective color Doppler method has yet to be established in the assessment of hand circulation before radial artery harvesting. Doppler studies so far have neglected the Doppler principle that the insonation angles should be less than 30degrees and have not been compared with any standard except the crude Allen test. We therefore introduced the snuffbox technique, measuring the radial artery at the anatomic snuffbox, which is the most distal area after harvesting. Color Doppler methods were compared with the stump pressure as a criterion standard. Methods: Maximal flow velocity and Doppler angles of the snuffbox, palmar artery, and ulnar artery were measured in 20 hands before and after radial artery harvesting. Stump pressure was measured during surgery. Results: Maximal flow velocity in the snuffbox decreased with radial artery compression and after radial artery harvesting. All the flow patterns in the snuffbox technique showed simultaneous reversal. Maximal flow velocity in the ulnar artery increased with radial artery compression and after radial artery harvesting. Maximal flow velocity in the palmar artery did not change significantly with radial artery compression or after radial artery harvesting. Doppler angles were 20.9degrees +/- 6.0degrees in the radial artery of the snuffbox, 82.5degrees +/- 6.1degrees at the palmar artery, and 81.0degrees +/- 7.6degrees at the ulnar artery. The changes in the snuffbox technique were highly correlated with the stump pressure ratio (P < .001). Conclusions: Among various color Doppler methods, the snuffbox technique was precise and reliable.