Microembolic signals and strategy to prevent gas embolism during extracorporeal membrane oxygenation

Abstract

BackgroundExtracorporeal membrane oxygenation (ECMO) supplies systemic blood perfusion and gas exchange in patients with cardiopulmonary failure. The current literature lacks of papers reporting the possible risks of microembolism among the complications of this treatment.In this study we present our preliminary experience on brain blood flow velocity and emboli detection through the transcranial Doppler monitoring during ECMO.MethodsSix patients suffering of heart failure, four after cardiac surgery and two after cardiopulmonary resuscitation were treated with ECMO and submitted to transcranial doppler monitoring to accomplish the neurophysiological evaluation for coma.Four patients had a full extracorporeal flow supply while in the remaining two patients the support was maintained 50% in respect to normal demand.All patients had a bilateral transcranial brain blood flow monitoring for 15 minutes during the first clinical evaluation.ResultsMicroembolic signals were detected only in patients with the full extracorporeal blood flow supply due to air embolism.ConclusionsWe established that the microembolic load depends on gas embolism from the central venous lines and on the level of blood flow assistance.The gas microemboli that enter in the blood circulation and in the extracorporeal circuits are not removed by the membrane oxygenator filter.Maximum care is required in drugs and fluid infusion of this kind of patients as a possible source of microemboli. This harmful phenomenon may be overcome adding an air filter device to the intravenous catheters.

Outcome in Patients with H1N1 Influenza and Cerebrovascular Injury Treated with Extracorporeal Membrane Oxygenation

“…e Numerous yellow, slightly sunken lesions are seen in the corpus callosum. f A lesion from the corpus callosum consists of a focus of infarction filled with macrophages, small amounts of hemosiderin and surrounding reactive changes in the form of reactive astrocytes and axonal spheroids (LH&E stain) Doppler ultrasound have been described as a complication of ECMO [8,9]. Air, like blood, causes hypointensity in MRI pulse sequences that are sensitive to magnetic susceptibility effects.…”

Extracorporeal Membrane Oxygenation and Cerebral Blood Flow Velocity in Children

“…It is, however, associated with significant neurologic morbidity and mortality including cerebral hemorrhage and cerebral ischemia (1–4). The pathophysiology for neurologic injury in these patients is likely multifactorial and includes: profound hypoxia and shock prior to initiation of ECMO support, alterations in the direction of cerebral blood flow following neck vessel cannulation (15–17), the nonpulsatile flow of venoarterial ECMO (18, 19), cerebral venous hypertension due to internal jugular vein occlusion (20), prolonged heparinization, and cerebral emboli (21). Little is known about how the initiation and continuation of ECMO support affects CBFV in children or the relationship of altered CBFV to neurologic insult.…”

Extracorporeal Membrane Oxygenation in the Adult

“…Hemolysis can be measured by decreasing hemoglobin levels, increasing plasma-free hemoglobin levels, and hyperbilirubinemia. 50 Air filters have been recommended for use with IV infusions as the membrane oxygenator filter may not arrest such microemboli. 47 Free heme stimulates heme oxygenase-1 48 production, converting heme into CO, iron, and biliverdin.…”