Cerebral microemboli detected by transcranial doppler in patients treated with extracorporeal membrane oxygenation.

INTRODUCTION: Cerebrovascular complications rate in patients treated with extracorporeal membrane oxygenation (ECMO) is about 7%. Ischemic stroke may be caused by solid or gaseous microemboli due to thrombosis within the circuit or cannula. Transcranial Doppler (TCD) is the only method able to detect microembolic signals (MES) in real time. The objective of this study was to detect possible MES by TCD in patients treated with veno-venous (VV) and veno-arterial (VA) ECMO and to test for a relation between the number of MES and the 6-month clinical outcome of these patients. METHODS: This is a monocentric observational prospective study in patients consecutively admitted and treated with ECMO at our regional ECMO referral center in 18 months. TCD detection of MES was performed in patients upon initiation of treatment and then repeated during treatment. RESULTS: Two hundred and forty-eight TCD monitoring were performed in 42 VV and 11 VA ECMO patients. MES were detected in 26.2% of VV ECMO patients and in 81.8% of VA ECMO patients (P < 0.001). In both subgroups of patients, no correlation was found between MES detection and extracorporeal flow velocities or aPTT values. In VA ECMO patients, an inverse correlation between left ventricular ejection fraction and MES grading was found (P = 0.037). In both groups, no clinical neurological impairments correlated to MES detection were found at 6 months follow-up. CONCLUSIONS: MES were found in both ECMO configurations; independently from their pathophysiology, MES do not seem to influence clinical outcome. Multicenter studies are still required with more extensive cases to confirm these results.

Single electroencephalographic patterns as specific and time-dependent indicators of good and poor outcome after cardiac arrest.

OBJECTIVE: To evaluate the prognostic value of single EEG patterns recorded at various time-frames in postanoxic comatose patients. METHODS: This retrospective study included 30-min EEGs, classified according to the definitions of continuity of background activity given by the American Clinical Neurophysiology Society. Isoelectric pattern was distinguished from other suppressed activities. Epileptiform patterns were considered separately. Outcome was dichotomised based on recovery of consciousness as good (Glasgow Outcome Scale [GOS] 3-5) or poor (GOS 1-2). RESULTS: We analysed 211 EEGs, categorised according to time since cardiac arrest (within 12h and around 24, 48 and 72h). In each time-frame we observed at least one EEG pattern which was 100% specific to poor or good outcome: at 12h continuous and nearly continuous patterns predicted good outcome and isoelectric pattern poor outcome; at 24h isoelectric and burst-suppression predicted poor outcome; at 48 and 72h isoelectric, burst-suppression and suppression (2-10µV) patterns predicted poor outcome. CONCLUSIONS: The prognostic value of single EEG patterns, defined according to continuity and voltage of background activity, changes until 48-72h after cardiac arrest and in each time-frame there is at least one pattern which accurately predicts good or poor outcome. SIGNIFICANCE: Standard EEG can provide time-dependent reliable indicators of good and poor outcome throughout the first 48-72h after cardiac arrest.