Table 1.

Summary of venoarterial ECMO scenarios with recommended management

	Scenario 1	Scenario 2	Scenario 3
Upper body Oxygenation	High	Low	Normal
Upper body PaCO2	Normal1	Normal/high3	Normal/high4
Upper body pH	Normal2	Normal/low3	High
Lower body Oxygenation	High	High	High
Lower body PaCO2	Normal1	Normal1	High
Lower Body pH	Normal2	Normal1	Low
Upper/lower body pH ratio	1	< 1	> 1
Management	Adjust sweep as needed to maintain adequate upper body pH and PaCO2	ECMO circuit reconfiguration to VAV ECMO or upper body VA ECMO	Increase sweep, creating lower body alkalemia in order to prompt the kidneys to eliminate bicarbonate

ECMO extracorporeal membrane oxygenation, PaCO₂ partial pressure of carbon dioxide in arterial blood, VA venoarterial, VAV venoarterial venous

¹Assuming sweep is adjusted to a normal pH

²In the absence of an independent metabolic acidosis or alkalosis

³Depending on how well preserved or impaired native lung ventilation may be

⁴Upper body PaCO₂ may be high as a compensatory response to the metabolic alkalosis