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].