Different Ways: The Stopcock Bridge

I happen to be traveling right now with three amazing ECMO Specialists, ECMOlogists in their own right, who are from three very different parts of the country and from three very different ECMO Centers.

Visiting another center, meeting another ECMO Specialist or attending an ECMO Conference is an opportunity to learn something new. I often take away something that would be just perfect to introduce into my own practice. I love hearing about a new procedure, policy or a piece of equipment that I would never have been exposed to at home. It is such a joy to venture out into the wider ECMO world and pick up new knowledge that will only make your practice better in the long run.

For example, this week I have learned a great deal about Adults. On ECMO. (I know!) All the IV access is on the patient – no access ports for IVs, medications, or lab draws on your ECMO circuit. All very novel for a pediatric based specialist. Such simplicity of the ECMO circuit has a very nice appeal!

It is also nice to share ideas with them as well. The idea of pressure monitoring of the oxygenator, the different ways to wean off ECMO and the notion of a stopcock bridge were just a few we shared.

The use of a bridge, whether a stopcock crystalloid filled one or a simple piece of tubing that remains clamped has always been a part of my practice. Never-ever thought of not having one. Many ECMO programs have eliminated this from their circuits, with reasons ranging from decreasing the possibility of component failure to decreasing connector and tubing use.

What are the benefits of a bridge? The bridge allows continuous flow through the ECMO circuit during any times of separation from the patient. This will maintain the integrity of the circuit and will allow patients to be returned to bypass after time passes. This may happen during emergency component changes or trial-off procedures. Without a bridge, the time that a patient is separated from the circuit must be monitored closely, for after a few minutes, the circuit will clot due to stagnate flow.

In pediatric ECMO the bridge can be an invaluable tool. For example, it allows delivery of super low flows in very small neonates. A 2 kg infant on 200cc/min is on 100 cc/kg! Hardly minimal flow. Using the stopcock bridge will allow the Specialist to wean delivered flow to the patient slowly to 10 – 20 cc/kg/min. This may be done by partially occluding an open bridge (with a Hoffman clamp) allowing recommended blood flow rates through the ECMO circuit, while still weaning flows that are actually delivered to the baby.

However, in adults, the necessity of weaning to such low flows, or having prolonged trial offs does not occur with any regularity. The simplicity of the circuitry allows most emergencies to be handled quickly and easily by just changing the entire circuit.

So – is having a bridge right or wrong? Only your program can decide. Assuming that one way is right (or wrong) is never a good thing. ECMO is ‘done’ in so many different ways – and there is something good about each!

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