Browsing by Author "Rivas, Rodrigo"
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Item Accuracy of Power Mode TranscranialDoppler in the Diagnosis of Brain Death(2015) Brunser, Alejandro; Lavados, Pablo; Cárcamo, Daniel; Hoppe, Arnold; Olavarría, Verónica; López, Javiera; Muñoz, Paula; Rivas, RodrigoBackground:The diagnosis of brain death (BD) is complex. For this reason, we aimed toevaluate the accuracy of power mode transcranial Doppler (PMD-TCD) in diagnosing BD.Patients and methods:Patients admitted to an intensive care unit between December 2003and January 2012 were included in this study if they were in a structural coma, had nocraniectomy, and were evaluated blind by a neurologist using PMD-TCD. The diagnosis of BDwas based on an evaluation that took into consideration the absence of sedative drugs, amedian blood pressure>60 mmHg, a body temperature>35 C, and the absence of brainstemreflexes. A neurosonologist followed a protocol using PMD-TCD that considered the examina-tion as positive for brain circulatory arrest given the presence of reverberating, small systolicpeaks or the disappearance of a previous signal present in both middle cerebral arteries andintracranial vertebral arteries.Results:A total of 74 patients were evaluated. In 61 (82.4%) patients the interval betweenboth evaluations was less than 1 hour. The sensitivity and specificity for the diagnosis of BD with PMD-TCD were 100% and 98%, respectively. The positive and negative likelihood ratios forBD were 45 and 0, respectively.Conclusion:PMD-TCD is accurate for the diagnosis of BD.Item Additional Information Given to a Multimodal Imaging Stroke Protocol by Transcranial Doppler Ultrasound in the Emergency Room: A Prospective Observational Study(2010) Brunser, Alejandro M.; Lavados, Pablo; Cárcamo, Daniel A.; Hoppe, Arnold; Olavarría, Verónica; Diaz, Violeta; Rivas, RodrigoBackground: Transcranial Doppler (TCD) ultrasound can demonstrate dynamic information. We aimed to evaluate whether TCD generates useful additional information in the emergency room after a multimodal stroke imaging protocol and also whether this modified the management of patients with cerebral infarction. Methods: Patients admitted between April 2006 and June 2007 with ischemic stroke of less than 24 h were subjected to a protocol consisting of non-contrast brain CT, computed tomography angiography, diffusion-weighted magnetic resonance imaging and then TCD within the following 6 h by an observer blinded to the results of imaging studies. Results: Seventy-nine patients were included. The imaging protocol was performed 457 (+/-346) min after stroke symptoms and TCD after 572 (+/-376) min. TCD provided additional information in 28 cases (35.4%, 95% CI 25.7-46.4). More that one piece of additional information was obtained in 6 patients. The most frequent additional information was collateral pathways. Multivariate analysis demonstrated that intracranial vessel occlusion was the variable most associated with additional information. In 7 patients (8.8%, 95% CI 4.3-17.1), additional information changed management: in 4 an additional angiography was performed, in 2 patients angiography was suspended and in 1 aggressive neurocritical care was indicated. Patients with NIHSS >10 were significantly more likely to have their initial treatment changed (p = 0.004). Conclusions: TCD can provide additional information to a multimodal acute ischemic stroke imaging protocol in a third of patients. This can result in changes in the management in some of these patients.Item Sonotrombolisis en el ataque cerebrovascular isquémico: once años de experiencia en Clínica Alemana de Santiago(Sociedad Médica de Santiago, 2014) Brunser, Alejandro; Hoppe, Arnold; Muñoz, Paula; Cárcamo, Daniel; Lavados, Pablo; Gaete, Javier; Roldán, Andrés; Rivas, RodrigoBackground: Sonothrombolysis (ST) is an emerging modality for the treatment of stroke. Aim: To assess the feasibility to perform ST in a Chilean hospital. Material and Methods: Patients attended at a private clinic with an acute ischemic stroke, between September 2002 and May 2013 and eligible for endovenous thrombolysis, were studied with a transcranial Doppler (Spencer PMD 100 or 150®). Those with an adequate sonographic window and a demonstrated arterial occlusion were monitored continuously with transcranial Doppler at the site of worst residual flow following the CLOTBUST study protocol. Results: One thousand twenty six patients were studied, of whom 136 received intravenous thrombolysis (rt-PA) and 61, aged 66 ± 18 years (59% males), were subjected to ST (7% of total). Their median National Institutes of Health Stroke Scale score was 14, the lapse from symptom onset to rt-PA was 127 minutes (43-223). Middle cerebral artery (MCA) occlusion was found in 88.5% of patients. Complete recanalization was achieved in 44.3% of patients. Sixty percent had Modified Rankin Scale of 0 to 2 at 3 months (95% confidence intervals (CI) 48.1 to 72). Case fatality was 9.8% and asymptomatic intracranial hemorrhage occurred in 9.8% (95% CI: 4.3 to 20.2). Conclusions: ST can be carried out in a complex medical center and is safe.Item Validez del Doppler transcraneal en el diagnóstico de muerte encefálica(2010) Brunser, Alejandro; Hoppe, Arnold; Cárcamo, Daniel; Lavados, Pablo; Roldán, AndrésS; Rivas, Rodrigo; Valenzuela, Marcela; Montes, José MiguelThe clinical diagnosis of brain death is complex. Aim: To evaluate the diagnostic accuracy of transcranial Doppler (TCD) for brain death. Patients and Methods: Patients seen on the intensive care unit of a private hospital between January 2004 to December 2008, were included if they were in structural coma, had no craniectomy and had a blind evaluation by a neurologist and TCD done in less than three hours. The diagnosis of brain death was based on a clinical evaluation that considered the absence of sedative drugs, median blood pressure >60 mmHg, body temperature over 35º Celsius and complete absence of brainstem reflexes. An expert neurosonologist, with a TCD-PMD-100, 2 Mhz transducer, used an institutional protocol that considers the examination as positive for brain circulatory arrest when there is presence of reverberating, small systolic peaks or the disappearance of a previous signal present on both middle cerebral arteries and intracranial vertebral arteries. Results: Fifty three patients were evaluated, 25 with clinical brain death. On 45 cases (84.9%), the interval between both evaluations was less than one hour. The sensitivity, specificity, positive and negative predictive values for the diagnosis of brain death with TCD were 100, 96, 96.1 and 100% respectively. Positive and negative likelihood ratios for brain death were 28 and 0, respectively. Conclusions: TCD is a valid and useful technique for the diagnosis of brain death and can be used on complicated cases.