The other main option for arterial line placement is the catheter-over-wire method, which includes the Seldinger and modified Seldinger techniques. The Seldinger and modified Seldinger techniques are similar in that they both involve entering the artery with a needle, advancing a wire into the artery through the needle, and then threading a catheter over the wire into the artery. Whereas the Seldinger technique uses separate components, the modified Seldinger technique uses an integrated needle-catheter-wire system.
Catheter-over-wire techniques can be used for superficial arteries (eg, the radial artery) and are preferred for the femoral artery. The modified Seldinger technique has been associated with increased overall success for arterial cannulation and has been recommended as the initial technique in female patients.[34] This method should not be used routinely for radial artery cannulation in neonates and infants, because the diameter of the vessel is too small to allow easy advancement of the guide wire.
Seldinger technique
Radial artery
Position, prepare, and drape the patient as previously described. Inject local anesthetic. Open the arterial line kit, and check the guide wire to make sure that it flows freely through the introducer needle. Palpate the artery with the second and third digits of the nondominant hand (see the image below).
Radial artery cannulation (Seldinger). Palpation o
Radial artery cannulation (Seldinger). Palpation of radial artery.
Attach the finder needle to a syringe. Puncture the skin proximal to your fingers over arterial pulsations, advancing the needle at a 30-45° angle toward the pulsation (see the image below).
Radial artery cannulation (Seldinger). Puncture of
Radial artery cannulation (Seldinger). Puncture of skin with finder needle.
Advance the needle with slight negative pressure until free return of blood is visualized in the syringe (see the image below). If initial return of blood is observed but the flow then ceases, the posterior wall of the vessel may have been punctured. Withdraw the needle slightly to try to restore blood flow to the needle.
Radial artery cannulation (Seldinger). Puncture of
Radial artery cannulation (Seldinger). Puncture of radial artery with return of blood.
Once free flow of blood is obtained, remove the syringe, and advance the guide wire into the artery (see the image below). If any resistance is encountered in advancing the guide wire, stop advancing the wire, reposition the needle, and attempt to cannulate the vessel again. If any resistance to repositioning the guide wire in the needle is met or if the guide wire is stuck in the needle, remove the needle and the wire together and start again.
Radial artery cannulation (Seldinger). Introductio
Radial artery cannulation (Seldinger). Introduction of guide wire into radial artery.
Before removing the needle, make a small skin incision with a scalpel at the site of needle entry into the skin (see the image below). Do not make a stab incision of the sort used in central line placement; such an incision may damage the underlying artery.
Radial artery cannulation (Seldinger). Skin incisi
Radial artery cannulation (Seldinger). Skin incision over needle.
Remove the needle while holding the guide wire in place, then advance a catheter over the wire into the artery (see the image below). If advancement of the catheter becomes difficult, a twisting motion can be used to facilitate catheter passage. Once the catheter is in place, remove the guide wire. Appropriate positioning of the catheter is confirmed by return of pulsatile blood from the catheter hub.
Radial artery cannulation (Seldinger). Advancement
Radial artery cannulation (Seldinger). Advancement of catheter over guide wire.
Attach the catheter to appropriate arterial line tubing (see the image below). Secure the catheter in place with sutures, tape or occlusive dressing.
Radial artery cannulation (Seldinger). Attachment
Radial artery cannulation (Seldinger). Attachment of arterial line tubing to catheter.
A dilator is usually not necessary; if it is used, it should be employed only to dilate the tract, not to enter the artery; the latter can cause excessive bleeding.
Femoral artery
Prepare and anesthetize the skin, locate the vessel, and insert the needle as previously described for the catheter-over-needle technique (see the image below). Because of the real deep location of the femoral artery, the needle should be inserted at a 45° angle.
Femoral artery cannulation (Seldinger). Puncture o
Femoral artery cannulation (Seldinger). Puncture of femoral artery with 18-gauge, 3-in. hollow introducer needle. Note 45° insertion angle.
Once the needle is in the artery, use a guide wire insertion adapter to advance the wire through the lumen of the needle (see the image below). Ensure that the guide wire passes easily, without resistance.[34]
Femoral artery cannulation (Seldinger). Guide wire
Femoral artery cannulation (Seldinger)