Browsing by Author "López, Javiera"
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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 Reliability of hand-held transcranial doppler with M-mode ultrasound in middle cerebral artery measurement(Elsevier, 2017) Muñoz, Paula; Gaete, Javier; Illanes, Sergio; López, Javiera; Olavarría, Verónica; Reccius, Andrés; Brinck, Pablo; González, Francisca; Cavada, Gabriel; Lavados, Pablo; Brunser, AlejandroPurpose: To determine the intra- and interrater agreement of mean flow velocity (MFV) and pulsatility index (PI) measurement in middle cerebral arteries, assessed by transcranial Doppler (TCD) with M-mode. Methods: Masked experienced neurosonologists performed TCD with M-mode using handheld probe in healthy adult volunteers. The Bland–Altman method for concordance and intraclass correlation coefficient were used. Results: Seventy-seven healthy volunteers and seven raters participated (3 on regular TCD shift and 4 off-shift). The intrarater absolute mean difference between measurements was 5.5 cm/s [95% confidence interval (CI), 4.7–6.3] for MVF and 0.073 (95% CI, 0.063–0.083) for PI. The difference between MFV measurements was significantly higher in off-shift raters (p = 0.015). The interrater absolute mean difference between measurements was 6.5 cm/s (95% CI, 5.5–7.5) for MVF and 0.065 (95% CI, 0.059–0.071) for PI. No influence was found for the middle cerebral artery side, volunteer's sex, or age, and there was no significant difference between raters. The intraclass correlation coefficient was 82.2% (95% CI 77.8–85.6) and 72.9% (95% CI 67.4–77.6) for MFV and PI, respectively. Conclusions: There exists good intra- and interrater agreement in MFV and PI measurements using M-mode TCD. These results support the use of this noninvasive tool and are important for clinical and investigational purposes.