TCD and Cerebral Circulatory Arrest in VA ECMO Patients.

To the Editor: Brain death (BD) diagnosis is a clinical diagnosis, in patients treated with veno-arterial extracorporeal membrane oxygenation (VA ECMO) too. Transcranial doppler (TCD) seems to be a feasible and reliable method to confirm BD also in patients treated with VA ECMO, when cardiac output is adequate (left ventricular ejection fraction [LVEF] > 20%) or supported by intra-aortic balloon pump (IABP).1 For the first time we have described and clearly categorized different TCD patterns detectable in non-BD VA ECMO patients, both with a pulsatile flow (due to preserved cardiac contractility or IABP inflation) and with a continuous, non-pulsatile arterial flow (absence of IABP and severely depressed or absent cardiac contractility). Out of our series of 23 VA ECMO patients evaluated by TCD, five evolved to BD. TCD findings of cerebral circulatory arrest (CCA) in these patients were summarized in Table 5 of our article.1 In all these patients, arterial blood flow was pulsatile. Four patients showed a LVEF > 20%, and one of these was supported with IABP; in one case, cardiac function was lower than 20% and supported by IABP. No patients with severely depressed or absent cardiac contractility and absence of IABP evolved to BD. Our findings suggest that, in the case of BD VA ECMO patients, TCD features are not different from those detected in non-ECMO patients, provided pulsatile blood flow is maintained either by adequate cardiac contractility or by IABP. As clearly stated in the article,1 the major limit of our research consists in the lack of BD patients with continuous arterial flow. At our knowledge, no data concerning TCD patterns of CCA in VA ECMO patients with no pulsatile blood flow have ever been published. We restate that in this particular hemodynamic condition, TCD BD confirmation could not be feasible. Concerning the reported TCD pattern of absence of signal in BD VA ECMO patients, we underline that TCD examination was performed according to Italian Guidelines,2 which are different from the Brazilian ones.3 In Italy, the absence of TCD signal is accepted as a diagnostic pattern of CCA in the case of a previous complete TCD examination, performed by the same neurosonologist in the same patient or when the finding of reverberating/systolic spikes pattern is detected in at least one artery evaluated by the same acoustic window.2 In our BD VA ECMO patients group, we found the absence of signal only in the basilar artery of one patient. We accepted this TCD pattern as diagnostic of CCA, because the adequacy of the sub-occipital acoustic window was demonstrated by the finding of systolic spikes detected in both vertebral arteries. Furthermore, TCD was performed twice in this patient, by the same neurosonologist, before BD evolution. We intend to submit a follow-up paper built upon our previous data with additional details and figures in order to better clarify our findings in each evaluated BD ECMO patient. Marinella MarinoniNeurosonology Unit, Neuromusculoskeletal and SensoryOrgans Department, Careggi Teaching Hospital,50134 Florence, Italy Giovanni CianchiEmergency and Trauma Intensive Care Unit and RegionalECMO Referral Centre, Careggi Teaching Hospital,50134 Florence, Italy Sara TrapaniNeurosonology Unit, Neuromusculoskeletal and SensoryOrgans Department, Careggi Teaching Hospital,50134 Florence, Italy Maria L. MigliaccioManuela BonizzoliEmergency and Trauma Intensive Care Unit and RegionalECMO Referral Centre, Careggi Teaching Hospital,50134 Florence, Italy Letizia GucciAntonella CramaroAndrea GalleriniFabio PicciafuochiNeurosonology Unit, Neuromusculoskeletal and SensoryOrgans Department, Careggi Teaching Hospital,Largo Brambilla 3, 50134 Florence, Italy Serafina ValenteIntensive Care Unit of Heart and Vessels Department,Careggi Teaching Hospital, Largo Brambilla 3, Italy Adriano PerisEmergency and Trauma Intensive Care Unit and RegionalECMO Referral Centre, Careggi Teaching Hospital,50134 Florence, Italy