a. Do not squeeze the tubing while attaching; air will

enter when the tubing is released.

b. If air is seen in the tubing, the catheters must be disconnected from the circuit. Prior to reconnection,

air is removed, and the catheters are reconnected as

described in E1.

2. Remove all sterile tubing clamps from the catheters,

and have a nonsterile assistant hold the catheters.

Nonsterile tubing clamps remain in place on the arterial and venous sides of the circuit at this juncture.

3. Place the patient on ECMO by removing the arterial

clamp, placing a clamp on the bridge (Fig. 33.9A), and

removing the venous clamp. This will remove all nonsterile clamps from the circuit.

Many centers are now using a “bloodless bridge”

that has sterile-heparinized saline with stopcock design;

thus, a clamp on the bridge is not necessary. The bridge

is left closed with the stopcock mechanism during cannulation so that only the clamps on the catheters need

to be removed.

4. Increase ECMO flow in 50-mL increments over 20 to

30 minutes, until adequate oxygenation is achieved

(usually at 120 mL/kg/min).

Transfusion may be needed if hypotension occurs at

this stage.

5. Decrease the ventilator settings and oxygen concentration gradually as the ECMO flows are increased.

Typical resting ventilator settings for VA ECMO

are at a rate of 10 to 15 breaths/min, a peak pressure

220 Section V ■ Vascular Access

limit of 15 to 20 cm H2O, and FiO2 of 0.21 to 0.30.

For VV ECMO, it is recommended to keep ventilator

settings at a rate of 20 to 30 breaths/min, a peak inspiratory pressure of 20 to 25 cm H2O, and FiO2 of 0.30

to 0.35.

F. Closure of the Neck Wound

1. Obtain radiographic confirmation of appropriate catheter position and achievement of an adequate flow rate

through the ECMO circuit prior to closure of the neck

wound.

2. Cut and remove traction sutures.

3. Approximate the skin with a running 4-0 Vicryl

(Ethicon) suture on an atraumatic needle.

4. Tie the Vicryl suture, and use the tails of the suture to

secure each catheter.

5. Tie catheters together with another silk tie.

6. Anesthetize the area behind the ear with 0.25%

Xylocaine with epinephrine.

7. Use 2-0 silk suture on a noncutting needle to place a

stitch behind the ear and tie around the catheter

to secure in place. Place a separate stitch for each

catheter.

8. Tie catheters together, dress the incision with povidone–

iodine ointment, and cover the area with semipermeable membrane dressing.

9. Secure the circuit tubing securely to the bedside to

reduce traction on the catheters.

G. Complications

1. Torn vessels, more commonly the vein

a. This risk is decreased if 6-0 Prolene stay sutures are

always used.

b. Do not attempt to use too large a catheter.

Fig. 33.9. Schematic view of converting from VA (A) to VV (B) ECMO. The double-lumen VV catheter

is “Y’d” together to make a double-lumen venous drainage catheter.