Anesthesia Student Survival Guide.pdf - Index of

232 ● AnesthesiA student survivAl Guide
Arterial Line Placement
Anatomy
The radial arterial line is the most commonly used, although other potential
arterial sites include ulnar, brachial, axillary, femoral and dorsalis pedis arteries.
The relevant anatomy for arterial line placement is shown in Fig. 15.1.
Although no longer recommended (because a positive test does not
correlate with impaired blood flow to the hand), an Allen’s test is sometimes
performed prior to insertion of the arterial line. First, press down firmly on
both the radial and ulnar arteries and occlude flow while the patient exsanguinates
the hand by making a tight fist repeatedly. Next, release the ulnar
artery from pressure: The hand should become pink within 6 s if the result is
normal. If it is abnormal, there is a theoretically higher risk of incomplete collateral
circulation and complications from arterial line placement.
Figure 15.1 Radial artery cannulation. The arm is immobilized in the supine position with
an armboard. The wrist is partially extended by placing a gauze roll underneath. The operator
locates the pulse with the index finger of the nondominant hand and follows the trajectory
of the artery with the third finger. The catheter is held like a pencil, with the needle bevel up.
The catheter is inserted 0.5–1 in. proximal to the wrist and advanced at a 30° angle. (With
permission from Criner, et al. Critical Care Study Guide: Text and Review, Springer, 2002).