icuECMO: Daily Care: Blood Pressure

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Daily Care: Blood Pressure:

The blood pressure should be measured invasively, traditionally in the right radial artery if the patient is on V-A ECMO.
Just like in any ICU patient, the MAP should be maintained at a high enough level to allow for adequate organ perfusion.
Vasopressors and inotropes may be used in ECMO patients in similar doses to patients who are not on ECLS.

The arterial line tracing of a patient on V-V ECMO should look like a traditional art-line tracing, and the patient should have a normal pulse pressure.
Changes in MAP have nothing to do with the flow, remember in V-V ECMO the pump provides no hemodynamic support.
Increases and decreases in MAP should be worked up in the same fashion as an ICU patient who is not on ECMO.

In V-A ECMO the flow from the pump is non-pulsatile, and the arterial line tracing loses a considerable amount of pulsatility.
We still target a MAP, just like in other ICU patients.
The jet of blood flow from the return cannula is retrograde and competes with the patient's native cardiac output, causing a huge afterload.
If the patient's heart cannot generate the force required to overcome this afterload, then the aortic valve will not open.
Pulse pressure and the presence of arterial line pulsations indicate some degree of opening of the aortic valve.
If there is no pulsatility in the arterial line then this may indicate the aortic valve is not opening, and this should be investigated further and corrected.

Interpreting a patient's intravascular volume status on ECMO is even more challenging that in a traditional ICU patient.
Intake and output should be monitored hourly.
Echocardiography (TTE or TEE) can be helpful in determining whether a patient will be fluid responsive by assessing ventricular filling.
The presence of chatter in the circuit may imply that the administration of fluid will generate an increase in output.
Fluids should only be given with the intent of improving the output of the pump and thereby improving oxygen delivery.
The CVP does not reflect fluid responsiveness or intravascular volume status in patients on ECLS.