Transcranial Doppler To Assess Cerebral Blood Flow In Patients On Extra Corporeal Membrane Oxygenation (P4.236)

OBJECTIVE: To establish feasibility of using TCD in assessing positive flow and microemboli in patients receiving Extra Corporeal Membrane Oxygenation(ECMO). BACKGROUND: In a patient after cardiac arrest, veno-arterial ECMO drains blood from the venous system, oxygenates it outside of the body and returns it to the arterial system. Multiple catheters necessitate deep sedation that renders neurological exam difficult to assess. Assuming that the brain function is only minimally impaired, ECMO is provided until the patient recovers. ECMO can improve survival rate dramatically in carefully selected patients. Low cerebral blood flow during initial shock and air bubbles introduced from the extracorporeal membrane can both affect cerebral perfusion and poor cognitive state despite hemodynamic recovery after ECMO. Early neurological evaluation using CT/MRI/EEG is not feasible hence all prognostication is deferred until after weeks or recovery. TCD can be useful to assess early cerebral hemodynamic changes to optimize initial resuscitation. TCD interpretation is based on pulsatile waveforms but patients on veno-arterial ECMO have non-pulsatile blood flow from continuous pumping action of external pump. One study has shown feasibility of measuring blood flow using TCD in sheep on ECMO with velocities of 62-75% of mean flow velocities measured before ECMO. Clinical studies in adult critically ill patients are extremely limited. DESIGN/METHODS: TCD images of two patients done during first 24 hours of initiation of veno-arterial ECMO for cardiac arrest were analyzed. RESULTS: TCDs showed non-pulsatile forward flow in all intracranial segments with numerous microembolic signals. Nuclear flow scan was normal in one patient with EEG showing generalized non-reactive waveforms in another. CONCLUSIONS: Hemodynamic changes in ECMO warrant early cerebral blood flow monitoring to protect the brain. TCDs can be an excellent modality to optimize early clinical management. Further data is required to establish normative ranges for nonpulsatile flow that correlates with good cerebral perfusion and good neurological recovery. Study Supported by: None Disclosure: Dr. Baghshomali has nothing to disclose. Dr. Reynolds has nothing to disclose. Dr. Sarwal has nothing to disclose.