188 Section V ■ Vascular Access

A B

C D

E F

Fig. 31.7. Radial artery cannulation by cutdown. A: Making transverse skin incision. B: Blunt dissection

with mosquito hemostat. C: Elevating artery with artery hook. D: Looping ligature around artery.

E: Introducing cannula into artery while gentle “back traction” is applied to suture. F: Cannula advanced

to hub.

Chapter 31 ■ Peripheral Arterial Cannulation 189

6. Wait 5 minutes for anesthesia.

7. Make transverse incision (0.5 cm) posteroinferior to

medial malleolus (see Fig. 31.4).

A vertical, rather than a transverse, incision is

optional. The former has the advantage that it offers the

opportunity to extend the incision cephalad, should the

posterior wall of the vein be perforated on the initial

attempt at cannulation. However, it has the disadvantage that it may be made too far lateral or medial to the

artery.

8. Identify artery by longitudinal dissection with mosquito

hemostat. The artery is usually found just anterior to

the Achilles tendon and adjacent to the tibial nerve.

9. Place mosquito hemostat behind artery, and loop 5-0

nylon suture loosely around it.

Be gentle, to avoid arteriospasm.

10. Elevate artery in wound with suture. Do not ligate

artery.

11. While stabilizing artery with suture, insert needle and

cannula, with bevel down.

12. Withdraw stylet and advance cannula to hub.

13. Remove nylon suture.

14. Close wound with 5-0 nylon suture (usually requires

only one suture).

15. See percutaneous method under E (Standard Technique,

steps 7 to 11) for fixation and care of cannula.

F. Obtaining Arterial Samples

Equipment

1. Gloves

2. Alcohol swabs

3. Sterile 2- × 2-inch gauze squares (for three-drop method)

A B

Fig. 31.8. A: Anatomic relations of the radial artery on the volar aspect of the wrist. B: Point for cannulation of the radial artery is indicated by the junction of the dotted lines. (Redrawn from Amato JJ, Solod E,

Cleveland RJ. A “second” radial artery for monitoring the perioperative pediatric cardiac patient. J Pediatr

Surg. 1977;12:715, with permission.)

4. 25-gauge straight needle (for three-drop method)

5. Appropriate-sized syringe for sample (heparinized if

sample is not processed on site)

6. Syringe with flush (for stopcock method)

7. Ice if necessary for sample preservation

8. Specimen labels and requisition slips

Technique I: Three-Drop Method

1. Wash hands and put on gloves.

2. Clean diaphragm of T connector with antiseptic solution and allow to dry.

3. Clamp T-connector tubing close to hub.

4. Place sterile gauze squares beneath hub.

5. Introduce 25-gauge needle through diaphragm and

allow 3 to 4 drops of fluid/blood to drip onto gauze.

6. Attach syringe to needle and withdraw sample.

7. Remove needle from diaphragm.

8. Unclamp T connector and allow residual pump pressure to flush catheter.

Technique II: Stopcock Method (a Three-Way

Stopcock Needs to be Interposed between the

Patient and the Transducer)

1. Wash hands and put on gloves.

2. Clean hub of stopcock with antiseptic solution.

3. Attach syringe to stopcock.

4. Turn stopcock off to infusion pump.

5. Aspirate waste (volume depends on length of tubing).

6. Using second syringe, withdraw sample.

7. Flush cannula slowly, over 30 to 60 seconds, with 0.5

mL of flush solution.

8. Open stopcock to pump, to allow for continued infusion of heparinized saline.