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.

This case series investigates whether painful electrical stimulation increases the early prognostic value of both somatosensory-evoked potentials and functional magnetic resonance imaging in comatose patients after cardiac arrest. Three single cases with hypoxic-ischemic encephalopathy were considered. A neurophysiological evaluation with an electroencephalogram and somatosensory-evoked potentials during increased electrical stimulation in both median nerves was performed within five days of cardiac arrest. Each patient also underwent a functional magnetic resonance imaging evaluation with the same neurophysiological protocol one month after cardiac arrest. One patient, who completely recovered, showed a middle latency component at a high intensity of stimulation and the activation of all brain areas involved in cerebral pain processing. One patient in a minimally conscious state only showed the cortical somatosensory response and the activation of the primary somatosensory cortex. The last patient, who was in a vegetative state, did not show primary somatosensory evoked potentials; only the activation of subcortical brain areas occurred. These preliminary findings suggest that the pain-related somatosensory evoked potentials performed to increase the prognosis of comatose patients after cardiac arrest are associated with regional brain activity showed by functional magnetic resonance imaging during median nerves electrical stimulation. More importantly, this cases report also suggests that somatosensory evoked potentials and functional magnetic resonance imaging during painful electrical stimulation may be sensitive and complementary methods to predict the neurological outcome in the acute phase of coma. Thus, pain-related somatosensory-evoked potentials may be a reliable and a cost-effective tool for planning the early diagnostic evaluation of comatose patients.

No abstract

No abstract

Our objective was to determine the role of asymmetry and the nature of microembolization on postoperative cognitive decline in patients who had undergone heart valve surgery. Continuous transcranial Doppler ultrasound was intraoperatively used for both middle cerebral arteries in 13 right-handed heart valve surgery patients to detect microembolization. The Trail Making Test A and B, Memory with 10/30 s interference, the Digit Span Test and Phonemic Fluency were performed preoperatively, at discharge and three months after surgery. Our data suggest that early and late postoperative psychomotor and executive functions may be sensitive to microemboli in the left, but not in the right middle cerebral artery. Moreover, solid and gaseous microemboli are both similarly associated with early postoperative cognitive decline while, surprisingly, late postoperative cognitive decline is more likely to be associated with gaseous than solid microemboli.