Browsing by Author "Valenzuela, Marcela"
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Item Accuracy of diffusion-weighted imaging in the diagnosis of stroke in patients with suspected cerebral infarct(American Heart Association, 2013) Brunser, Alejandro; Hoppe, Arnold; Illanes, Sergio; Díaz, Violeta; Muñoz, Paula; Cárcamo, Daniel; Olavarría, Verónica; Valenzuela, Marcela; Lavados, PabloBACKGROUND AND PURPOSE: The accuracy of diffusion-weighted imaging (DWI) for the diagnosis of acute cerebral ischemia among patients with suspected ischemic stroke arriving to an emergency room has not been studied in depth. METHODS: DWI was performed in 712 patients with acute or subacute focal symptoms that suggested an acute ischemic stroke (AIS), 609 of them with AIS. RESULTS: DWI demonstrated a sensitivity of 90% and specificity of 97%, a positive likelihood ratio of 31 and a negative likelihood ratio of 0.1 for detecting AIS. The overall accuracy was 95%. Of those patients who demonstrated abnormal DWI studies, 99.5% were AIS patients, and of those patients with normal DWI studies 63% were stroke mimics. CONCLUSIONS: DWI is accurate in detecting AIS in unselected patients with suspected AIS; a negative study should alert for nonischemic conditions.Publication Covid-19 en trasplantados renales hospitalizados: análisis del registro multicéntrico durante la primera ola de la pandemia en chile(2024) Pefaur, Jacqueline; Toro, Luis; Badilla, Ximena; Ardiles, Leopoldo; Boltansky, Andrés; Rosatti, Pía; Tapia, Beatriz; Rocca, Ximena; Mur, Paola; Fernández, Alicia; Castillo, Alvaro; Díaz, Carolina; Elgueta, Leticia; García, Francisco; Müller, Hans; Mansilla, Rodrigo; Muñoz, Carolina; Salvatici, Marcelo; Selame, María Esperanza; Valenzuela, Marcela; Zamora, Daniela; Enciso, Giovanni; Panace, Rita; Cabrera, Sebastián; Ortíz, Ana Mireya; Mardones, Sandra; Oshiro, Carolina; Sánchez, Juan Eduardo; Lorca, Eduardo; Torres, RubénIntroduction: The severity of COVID-19 infection in kidney transplant patients has been well-documented. Objectives: This study aims to determine the epidemiological and clinical data and identify predictors of poor prognosis during the epidemic’s early stages. Material and methods: This is a national semi-prospective, multicenter study of subjects with functioning grafts who were infected during the first wave of the pandemic in Chile between March 1 and September 31, 2020. Results: during this period, we recorded the hospitalization of 97 adult patients throughout the entire national territory. The average age was 52.5 years, 62% men, 45% hypertensive, 11% coronary, 10% diabetic, and 5% with chronic obstructive pulmonary disease, with an average post-transplant follow-up of 7.2 years and an average previous renal function of 47.7ml/min/1.7m2 (CKD-EPI formula). Between the onset of symptoms and diagnosis, there was an average period of 4.8 days, with a predominance of cough (44%), dyspnea (42%), and fever (42%). 34% developed acute kidney injury, and 36% of them required dialysis support. The lethality was 30%, prevailing in those with multiple organ failure (80%) and those who required invasive mechanical ventilation (52%). In the multivariate analysis, the best predictors of mortality were older age (OR: 2.92) and living in a low-income commune (OR: 2.35). Conclusions: This national project of the Chilean Society of Nephrology provided valuable information for monitoring the epidemiological evolution of the pandemic. It also helped to propose priority vaccination strategies, adjust immunosuppressive therapy, and design logistical aspects to reduce the risks for transplant patients.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.