Before Cannulation of the Radial Artery: Collateral Arterial Supply Evaluated by Strain-Gauge Plethysmography

Systolic arterial pressure in the thumb was measured using strain-gauge plethysmography before and after compression of the radial artery in 259 patients (aged 11–75 years), undergoing vascular or open-heart surgery. In 38 hands (in 27 patients aged 37–75 years), manual compression of the radial artery reduced the arterial pressure in the thumb to less than 40 mmHg (5.3 kPa), and consequently the collateral ulnar arterial supply was judged to be inadequate. Because 27 out of 259 patients (10.4%) would be without adequate blood supply to one or both thumbs following occlusion of the radial arteries, cannulation of the radial artery should be performed only after ensuring the presence of an adequate collateral ulnar arterial supply.