6. Accomplish cannulation of artery (Fig. 31.5).

Method A (Preferred for Small Premature

Neonates) (Fig. 31.6)

a. Puncture artery directly at an angle of 10 to

15 degrees to the skin, with the needle bevel down.

b. Advance slowly. There will be arteriospasm when

the vessel is touched, and blood return may be

delayed.

c. Withdraw needle stylet (blood should appear in the

cannula) and advance cannula into artery as far as

possible.

Method B (Fig. 31.5B)

a. Pass needle stylet (with bevel up) and cannula

through artery at 30- to 40-degree angle to skin.

b. Remove stylet and withdraw cannula slowly until

arterial flow is established.

c. Advance cannula into artery.

The inability to insert the cannula into the lumen

usually indicates failure to puncture the artery centrally. This often results in laceration of the lateral

wall of the artery with formation of a hematoma,

which can be seen on transillumination.

7. Attach cannula firmly to T connector and gently flush

with 0.5 mL of heparinized solution, observing for evidence of blanching or cyanosis.

8. Apply iodophor ointment (optional) to puncture site.

9. Suture cannula to skin with 5-0 nylon suture if desired.

Fig. 31.2. Anatomic relations of the

major arteries of the wrist and hand.

Chapter 31 ■ Peripheral Arterial Cannulation 185

This step may be omitted as long as cannula is

securely taped (Fig. 27.4); use of sutures may produce a

more unsightly scar.

10. Secure cannula as done with peripheral IV line, as

shown in Fig. 27.4. Transparent semipermeable dressing may be used in place of tape to allow continuous

visualization of skin entry site. Guarantee that all digits

are visible for frequent inspection.

11. Maintain patency by attaching T connector to extension

tubing or arterial pressure line to run 0.5 to 1 mL/h of

heparinized flush solution by constant infusion pump.

12. Change IV tubing and flushing solution every

24 hours.

Radial Artery Cutdown

Cutdown technique may be required for the very small neonate, because trauma to the artery causes vasospasm, which

makes percutaneous cannulation of a small vessel very difficult.

1. Technique I: Cutdown at wrist

The artery is initially exposed by cutdown, and a

catheter is inserted under direct vision.

Fig. 31.3. A: Anatomic relations of

dorsalis pedis artery. B: White arrow

shows anatomic location of dorsalis

pedis artery.

A

B