Bartels_Hensley's Practical Approach to Cardiothoracic Anesthesia, 7e

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8. Extracorporeal Membrane Oxygenation for Pulmonary or Cardiac Support

CLINICAL PEARL When determining readiness for decannulation from venovenous ECMO, sweep gas flow should be dis continued to assess adequacy of native gas exchange. When weaning venoarterial ECMO, extracorpo real blood flow is typically reduced to assess hemodynamic readiness for decannulation. In venoarterial ECMO, sweep gas flow should always be maintained; discontinuation of sweep gas flow would lead to hypoxemia from a right-to-left shunt. VII. Extracorporeal Membrane Oxygenation Transport A. Patients with severe, refractory respiratory or cardiac failure who would otherwise benefit from ECMO support may be at facilities without ECMO capabilities and yet be too unstable to transport to an ECMO-capable center. Under such circumstances, mobile ECMO transport teams may improve these patients’ outcomes by performing ECMO cannulation at the origin hospital and transporting them to specialized centers capable of providing ongoing ECMO management. B. ECMO transport has been demonstrated to be safe and feasible. This highlights the poten tial role of regionalization of ECMO in order to maximize outcomes by referring patients to high-volume centers with greater experience and expertise. 25 VIII. Complications A. Potential complications are inherent with any invasive intervention, especially among patients with severe underlying critical illness, and must be weighed against the potential benefit of the intervention. Complication rates for ECMO vary greatly based on center experience, manage ment strategies, devices used, and patient characteristics. 1. Commonly encountered hematologic complications include hemorrhage and thrombotic/ thromboembolic events, the severities of which are heavily influenced by center-specific anticoagulation practices and patient-specific factors. Less common hematologic compli cations include hemolysis, thrombocytopenia, disseminated intravascular coagulation, ac quired von Willebrand disease, and HIT. a. The diagnosis of HIT during ECMO should be made based on appropriate clinical cri teria (eg, 4T score). If HIT is suspected, a heparin antibody test should be performed as an initial screening test, followed by a serotonin release assay if the heparin antibody test is positive. Alternate anticoagulants (eg, direct thrombin inhibitors) may be used for anticoagulation while awaiting the results of serologic testing. 2. Infectious complication rates vary substantially by center and by the manner in which ECMO-related infections are defined. Standardized infection control practices should be used for ECMO insertion, maintenance, and removal. 3. Other complications, such as limb ischemia, limb engorgement, and vascular perforation, may be a consequence of certain ECMO cannulation approaches and techniques, and will be influenced by the experience of the provider performing the procedure and the use of radiographic guidance. Prompt Doppler examination in the ICU will guide interventions. IX. Economic Considerations A. The implementation across a health system of any novel technology, particularly for commonly encountered diseases, has to take into consideration the resources it may require, including financial resources that will vary greatly by region. There are limited data on the economic impact of ECMO use in ARDS, and even less for ECMO for cardiac failure. The CESAR trial, conducted within the United Kingdom’s National Health Service, estimated that referral for consideration of ECMO led to a gain of 0.03 quality-adjusted life-years (QALYs) at 6-month follow-up, with the predicted cost per QALY of ECMO to be £19,252 (95% CI £7,622-59,200). B. Any future prospective randomized studies assessing the role of ECMO in cardiopulmonary failure would benefit from characterizing the economic impact in addition to the clinical out comes, so that hospitals and health care systems can best decide how to allocate the resources appropriately.

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