218 Section V ■ Vascular Access

There will be slight impedance to catheter advancement at the thoracic inlet—pushing against resistance

will tear the vein. Use gentle downward and posterior

pressure.

6. Secure, as for the artery, and back blood into the catheter by pressing gently on the liver.

7. If desired, pack the wound with absorbable gelatin

sponge soaked in topical thrombin or commercially

available topical fibrin sealant, to assist in hemostasis.

Cryoprecipitate and topical thrombin can be used

to form a fibrin clot if dropped onto the field from separate syringes in a one-to-one concentration. Note: If

they are mixed together in one syringe, they will form a

solid clot in the syringe. A similar product is also commercially available as Tisseel-HV Fibrin Sealant

(Baxter Hyland Division, Glendale, California).

8. Confirm catheter placement by chest radiography and/

or cardiac echocardiography, if the patient is stable

(Fig. 33.7) (10, 11). If the patient is unstable, he or she

can be placed on ECMO and the radiograph taken

when adequate oxygenation is achieved but prior to

closing the surgical wound.

Venovenous Extracorporeal Membrane

Oxygenation—Cannulation

More than 60% of neonatal ECMO patients reported in

the ELSO registry have received treatment with VA bypass

(12). In neonates with respiratory failure, VA ECMO is

gradually being replaced by a venovenous (VV) technique,

which uses a single double-lumen catheter (Fig. 33.8).

The catheter is placed in the right atrium, where blood is

drained and reinfused into the same chamber, thus requiring cannulation of only the right jugular vein, and sparing

the carotid artery. Other advantages of VV ECMO include

maintenance of normal pulsatile blood flow, and the theoretical advantage that particles entering the ECMO circuit

enter by way of the pulmonary rather than the systemic circulation. The design of the original VV catheter resulted

in significant recirculation, limiting its use when ECMO

flows >350 mL/min were required. Research by RaisBahrami et al. (13) resulted in development of a new

catheter design that significantly lowers the degree of recirculation. The double-lumen catheter should be placed

within the right atrium, directing the oxygenated blood

from the return lumen through the tricuspid valve to minimize recirculation. This catheter design in 12-, 15-, and

18-Fr sizes allows the use of VV ECMO in a greater number of infants (14).

Fig. 33.7. Radiograph at cannulation, showing proper placement of the arterial and venous catheters. Note the radio-opaque

dot indicating the end of the Bio-Medicus venous extracorporeal

membrane oxygenation catheter (arrow).

cm 5 14 FR

Fig. 33.8. Schematic of the VV ECMO

catheter placed in the mid-right atrium.

(From Short BL. CNMC ECMO Training

Manual. 2005, with permission).