Contrast echocardiography in patients undergoing extra-corporeal membrane oxygenation (ECMO)
Though the use of UEAs during TTE have been evaluated in COVID-19 patients who were spontaneously breathing or on mechanical ventilation[53], their use during TTE in the setting of ECMO for COVID-19 ARDS can be potentially problematic. UAE can trigger an air bubble alarm, which is integrated in ECMO circuits as a safety measure. This can result in stoppage of the ECMO circuit forward flow or engaging a ‘’Zero-flow mode” which can result in rapid deterioration of hypoxic patients who are dependent on ECMO flow.(58) Bleakley et al used a protocol that involves the deactivation of air-bubble alarms before administration of contrast to avoid such potential complication.[54].