Page 604 - Clinical Application of Mechanical Ventilation

570 Chapter 17

Blood Returned
to Patient
Blood out
to ECMO
Circut
Right
Internal Carotid
Jugular Vein Artery

Aortic
Arch
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Right
Atrium

Figure 17-5 Venoarterial route of ECMO setup. Blood is drawn from the right atrium via the in-
ternal jugular vein. The oxygenated blood is returned to the aortic arch via the right carotid artery.

Mechanisms of Bypass

In the venoarterial Two types of ECMO can be done: venoarterial and venovenous.
route, blood goes from the
right atrium (via the internal Venoarterial. In the venoarterial route, blood is drawn from the right atrium via the
jugular vein) to the aortic arch internal jugular vein. The oxygenated blood is returned to the aortic arch via the right
(via the right common carotid
artery). This route oxygenates common carotid artery, as shown in Figure 17-5. Venoarterial ECMO not only oxy-
the blood and supports the
patient’s cardiac function. genates the blood but also supports the cardiac function of the patient, because the
blood return to the aortic arch is supported by the ECMO machine. For this reason,
the venoarterial route is most commonly used for the ECMO procedure (Donn, 1990).
Venovenous. In the venovenous route, blood is removed from the right atrium via
In the venovenous route, a catheter inserted in the right internal jugular vein. The oxygenated blood is re-
blood goes from the right
atrium (via the right internal turned to the right atrium through a catheter inserted via the femoral vein. This
jugular vein) and returns method oxygenates the blood and does not support cardiac output.
to the right atrium (via the
femoral vein). This route oxy- In the venovenous method, blood flow from right to left heart remains the sole
genates the blood only and
does not support the patient’s function of the heart.
cardiac function.
ECMO Circuit. The ECMO circuit uses a modified heart-lung bypass machine consist-
ing of a venous-blood drainage reservoir, a blood pump, the membrane oxygenator
where the exchange of O and CO takes place, and a heat exchanger to maintain
2
2
temperature. Figure 17-6 depicts a typical ECMO circuit.
Complications

Complications of ECMO are both mechanical and physiologic. Common physi-
ologic complications of ECMO are those related to bleeding, secondary to the high

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