When we talk about limb complications during ECMO, ischemia is often the main concern. For good reason: distal limb ischemia is a serious risk that too often leads to amputation. But it’s not the only threat to life and limb. Hyperperfusion can be just as dangerous 

Too much flow through a distal perfusion catheter (DPC) can harm tissue or cause a vascular injury. It’s a risk that can develop quietly and progress quickly if it’s not detected in time.

Rethinking the Perfusion Paradigm 

DPCs are widely used to maintain limb viability during femoral cannulation in VA ECMO. But once the DPC is in place, how confident can we be that the flow is optimal?

The truth is, many teams operate with limited visibility into actual flow rates through these catheters. While underperfusion garners immediate concern, excessive flow can also be harmful. In the more severe cases, it can lead to vascular injury or irreversible soft tissue damage.

Even minor shifts in ECMO circuit dynamics or patient positioning can alter distal perfusion. Without direct flow measurement, these changes may go unnoticed until clinical signs emerge, which is when intervention often becomes more difficult. Continuous, real-time monitoring gives clinicians the insight they need to detect and address fluctuations early, before complications escalate.

ELSO Guidelines and the Need for Quantitative Flow

The Extracorporeal Life Support Organization (ELSO) recommends dual monitoring to assess limb perfusion during VA ECMO:

• Tissue oxygenation via NIRS: Maintain saturation above 50%, ideally >60%, with a <20% difference between limbs
• Quantitative flow monitoring: Target at least 100 mL/min through the distal perfusion catheter (DPC)

These metrics serve complementary roles.

NIRS reflects tissue oxygenation, helping detect ischemia.

Flow monitoring confirms the actual volume of blood reaching the limb, helping detect both under- and over-perfusion. By combining both, clinicians can avoid the false reassurance that may come from seeing a “normal” NIRS reading in the presence of fluctuating or excessive flow and vice versa. 

This dual approach helps protect against the full spectrum of perfusion-related complications, including hyperperfusion.

Add Flow Monitoring With Confidence

Managing distal limb perfusion on ECMO is a delicate balance. Both ischemia and hyperperfusion can have serious consequences, which is why precise monitoring matters. 

With Transonic’s flow measurement systems, you can track DPC flow in real time – no circuit modifications, no guesswork.

Learn more about flow measurement for distal limb perfusion.