Cardiothoracic critical care PA Brendan Riordan (@concernecus) shows us his initial approach to the patient in cardiogenic shock, including initiating mechanical support, managing ECMO (plus Impella), and eventual weaning and discontinuation of support.
- Anticoagulation on VA ECMO can be titrated to bleeding risk, with a balance between bleeding and circuit longevity—the latter being more than an inconvenience, as changing the circuit in a patient fully dependent on the pump is fraught. Anti-Xa levels are more reliable than the PTT. In a patient with HIT, you may be able to treat through it with bivalirudin, as the heparin-bonded circuit usually cannot be switched out.
- “Hypoxemia” on VA ECMO is either regional hypoxemia/North-South syndrome/harlequin syndrome, or oxygenator failure. Rule out the latter by checking a post-oxygenator ABG or just looking to ensure the outflow blood is bright red. Rule in the former by evaluating the ABG or SpO2 from the right upper extremity.
- Preemptively placing an anterograde perfusion catheter in the femoral artery is not absolutely mandatory, but is probably simpler and perhaps safer than placing one reactively.
- A PA catheter is more useful for weaning ECMO than during the period of full support.
- Readiness for weaning is evaluated by recognition of improving cardiac pulsatility, followed by a trial of weaning down pump flow, and finally decannulation in the OR. Consider leaving the Impella if there are any lingering concerns.
- How to monitor anticoagulation during ECMO: Saifee NH, Brogan TV, McMullan DM, et al. Monitoring Hemostasis During Extracorporeal Life Support. ASAIO J. 2020;66(2):230–237.