
Relatively Increased CO2 Delivered to the Brain From the Descending Aorta Leading to an Elevated Respiratory Rate Causing Differential Hypocapnia (RIDDLER or East-West Syndrome): New Pitfalls in Awake Peripheral V-A ECMO
This article describes a newly recognized physiological phenomenon, RIDDLER (East-West Syndrome), in patients on awake peripheral V-A ECMO. It occurs when CO2-rich blood from the ECMO circuit reaches the brain, triggering an increased respiratory rate despite paradoxically low CO2 levels in the right radial artery. This leads to a cycle of worsening hypercapnia, respiratory distress, and potential neurological injury. Proper CO2 monitoring strategies are needed to prevent mismanagement.