Before performing puncture or cannulation of the radial artery, what should you do?

a. Fix and tighten a tourniquet above the an-tecubital fossa.
b. Perform the Allen test to ensure collateral circulation.
c. Inject heparin into the adjoining subcuta-neous tissues.
d. Apply firm pressure to the arterial site for 5 min.

ANS: B
Box 19-2 outlines the basic procedure for radial artery puncture of adults.