Efectos de la dosis de carga y tasa de infusión continúa de dexmedetomidina (precedex) sobre la función del ventrículo izquierdo evaluada por ecocardiografía doppler en caninos sanos

Tesis (Magister en Ciencias Veterinarias).-- Universidad de La Salle. Facultad de Ciencias Agropecuarias. Maestría en Ciencias Veterinarias, 2014

Brachial artery peak velocity variation to predict fluid responsiveness in mechanically ventilated patients

INTRODUCTION Although several parameters have been proposed to predict the hemodynamic response to fluid expansion in critically ill patients, most of them are invasive or require the use of special monitoring devices. The aim of this study is to determine whether noninvasive evaluation of respiratory variation of brachial artery peak velocity flow measured using Doppler ultrasound could predict fluid responsiveness in mechanically ventilated patients. METHODS We conducted a prospective clinical research in a 17-bed multidisciplinary ICU and included 38 mechanically ventilated patients for whom fluid administration was planned due to the presence of acute circulatory failure. Volume expansion (VE) was performed with 500 mL of a synthetic colloid. Patients were classified as responders if stroke volume index (SVi) increased >or= 15% after VE. The respiratory variation in Vpeakbrach (DeltaVpeakbrach) was calculated as the difference between maximum and minimum values of Vpeakbrach over a single respiratory cycle, divided by the mean of the two values and expressed as a percentage. Radial arterial pressure variation (DeltaPPrad) and stroke volume variation measured using the FloTrac/Vigileo system (DeltaSVVigileo), were also calculated. RESULTS VE increased SVi by >or= 15% in 19 patients (responders). At baseline, DeltaVpeakbrach, DeltaPPrad and DeltaSVVigileo were significantly higher in responder than nonresponder patients [14 vs 8%; 18 vs. 5%; 13 vs 8%; P < 0.0001, respectively). A DeltaVpeakbrach value >10% predicted fluid responsiveness with a sensitivity of 74% and a specificity of 95%. A DeltaPPrad value >10% and a DeltaSVVigileo >11% predicted volume responsiveness with a sensitivity of 95% and 79%, and a specificity of 95% and 89%, respectively. CONCLUSIONS Respiratory variations in brachial artery peak velocity could be a feasible tool for the noninvasive assessment of fluid responsiveness in patients with mechanical ventilatory support and acute circulatory failure. TRIAL REGISTRATION ClinicalTrials.gov ID: NCT00890071.

Sensibilidad y especificidad del ecocardiograma transtorácico para el diagnóstico de enfermedad coronaria

Introducción: La enfermedad coronaria es la principal causa de muerte en Colombia y el mundo en personas mayores de 45 años (1, 2). Con la variación en los perfiles epidemiológicos se espera que aumente su prevalencia y costo, disminuyendo la mortalidad. En el estudio diagnóstico de enfermedad coronaria, se realizan múltiples pruebas paraclínicas, dentro de estas, el ecocardiograma es muy utilizado y sus recomendaciones de uso se basan en estudios de hace más de 10 años (3). Metodología: Se realizó un estudio de prueba diagnóstica para determinar las características operativas del ecocardiograma transtorácico para el diagnóstico de enfermedad coronaria frente al cateterismo cardiaco en pacientes con dolor torácico. Resultados: Se analizaron 290 pacientes con una edad promedio de 67 años y 68% hombres; el 74.1% tenía hipertensión arterial y el 24.5% de diabetes mellitus. En el 61% de los pacientes se evidenció enfermedad coronaria por angiografía. La sensibilidad del ecocardiograma transtorácico para enfermedad coronaria fue del 70%, especificidad del 55%, valor predictivo negativo del 54% y valor predictivo positivo del 71%; con una efectividad del 65% y una capacidad predictora del 60.6% (p=0.02). Discusión: La anatomía coronaria fue similar a la descrita previamente, siendo las lesiones multivaso presente en un 41% y la lesión de un vaso fue del 22% (4, 5). Teniendo en cuenta la sensibilidad del 70% y especificidad del 55%, la facilidad de acceso, características no invasivas y el bajo costo; nos permiten recomendar utilizarlo como guía diagnóstica en el contexto del dolor torácico en el servicio de urgencias.

Correlación y concordancia entre ecocardiografía y cateterismo cardiaco derecho para determinación de la presión sistólica de arteria pulmonar

Introducción. El cateterismo cardiaco derecho representa el estándar de referencia para el diagnóstico de hipertensión pulmonar, sin embargo el rendimiento de la ecocardiografía como estudio inicial ha mostrado buena correlación con las variables medidas por cateterismo. El presente estudio pretende describir el grado de correlación y concordancia entre la ecocardiografía y el cateterismo cardiaco derecho para la medición de la presión sistólica de la arteria pulmonar. Materiales y métodos. Se realizó un estudio observacional retrospectivo de los pacientes sometidos a cateterismo cardiaco derecho entre los años 2009 a 2014 y se compararon con los datos de ecocardiograma más cercano a este cateterismo, teniendo en cuenta la presión sistólica de la arteria pulmonar (PSAP) en las dos modalidades diagnósticas mediante correlación y concordancia estadística según los coeficientes de Pearson y el índice de Lin respectivamente. Resultados. Se recolectaron un total de 169 pacientes con un índice de correlación (r) obtenido para la medición de PSAP del total de la muestra de 0.73 p < 0.0001 mostrando un grado de correlación alto para toda la muestra evaluada. El análisis de concordancia obtenido para toda la población a partir del índice de Lin fue de 0.71 lo que determinó una pobre concordancia. Discusión. Se encontró buena correlación entre ecocardiografía y cateterismo cardiaco derecho para la medición de la PSAP, sin embargo la concordancia entre los métodos diagnósticos es pobre, por tanto el ecocardiograma no reemplaza al cateterismo cardiaco derecho como estudio de elección para diagnóstico y seguimiento de pacientes con hipertensión pulmonar.

Diagnostic agreement between panoramic radiographs and color doppler images of carotid atheroma

The aim of this study was to investigate the agreement between diagnoses of calcified atheroma seen on panoramic radiographs and color Doppler images. Our interest stems from the fact that panoramic images can show the presence of atheroma regardless of the level of obstruction detected by color Doppler images. Panoramic and color Doppler images of 16 patients obtained from the archives of the Health Department of the city of Valença, RJ, Brazil, were analyzed in this study. Both sides of each patient were observed on the images, with a total of 32 analyzed cervical regions. The level of agreement between diagnoses was analyzed using the Kappa statistics. There was a high level of agreement, with a Kappa value of 0.78. In conclusion, panoramic radiographs can help detecting calcifications in the cervical region of patients susceptible to vascular diseases predisposing to myocardial infarction and cerebrovascular accidents. If properly trained and informed, dentists can refer their patients to a physician for a cardiovascular evaluation in order to receive proper and timely medical treatment.

Evaluation of left ventricular diastolic echocardiographic parameters in healthy dogs by pulsed-wave Doppler

Left ventricular diastolic dysfunction plays an important role on heart failure progression. In order to obtain additional reference values of left ventricular diastolic parameters and investigate influence of common variables, peak E wave (peak E), peak A wave (peak A), E/A ratio (E/A), E wave deceleration time (EDT) and isovolumic relaxation time (IRVT) were studied in 40 clinically healthy dogs, by pulsed wave Doppler. The following values were obtained: peak E = 0.747 ± 0.117 m/s, peak A = 0.487 ± 0.062 m/s, E/A = 1.533 ± 0.198, EDT = 88.7 ± 9.2 ms and IRVT = 0.080 ± 0.009 s. Some parameters were influenced by heart rate (peak E, peak A and IRVT), by age (peak A and E/A) and by body weight (TRIV). Gender influence was absent. Values obtained can be used as reference for canine specimens but its interpretation should consider on the influence of related variables.

Valores da pressão arterial em cães pelos métodos oscilométrico e Doppler vascular

Foram comparados dois métodos não-invasivos de medida da pressão arterial, o Doppler vascular e o oscilométrico, com o objetivo de estabelecer parâmetros que possam auxiliar no diagnóstico seguro da hipertensão arterial. Para tal, foram utilizados 45 cães, machos e fêmeas, distribuídos em três grupos de acordo com o peso, pequeno, médio e grande porte. Em cada animal, procedeu-se a mensuração por meio do Doppler vascular e, em seguida, do oscilométrico. Na obtenção da pressão arterial sistólica, não houve diferença entre os métodos nos três grupos de animais, porém, na obtenção da pressão arterial diastólica, houve diferença estatística entre o Doppler vascular e o oscilométrico nos grupos de animais de pequeno e médio porte. Pôde-se concluir que valores confiáveis de pressão sistólica podem ser obtidos tanto por meio do Doppler vascular quanto do oscilométrico. Os valores da pressão arterial diastólica obtidos pelos dois métodos não se correlacionam, principalmente nos animais de pequeno e médio porte.

Avaliação dos fluxos das valvas aórtica e pulmonar com ecocardiografia Doppler pulsátil em cães clinicamente sadios

Avaliaram-se com Doppler pulsátil os fluxos das valvas aórtica (AO) e pulmonar (Pul) por meio de análise qualitativa (presença de regurgitações valvares e características do espectro avaliado) e quantitativa, com obtenção de parâmetros ecocardiográficos como velocidades máxima (V. Max.) e média (V. Me.), integral de velocidade (VTI), tempo de aceleração (TA) e ejeção (TE), de 30 cães considerados clinicamente sadios por meio de exames físico, laboratoriais, eletrocardiográfico, ecocardiográfico (modos uni e bidimensional), radiográfico de tórax e mensuração da pressão arterial sistêmica. Obtiveram-se os seguintes resultados para os referidos parâmetros: V.max. AO= 1,22± 19,38m/s; V. Me. AO= 0,72± 0,08m/s; VTI AO= 0,14± 0,02m; TA AO= 38,80± 11,29ms; TE AO= 197,90± 24,77ms; V. Max. Pul= 0,95± 0,18m/s; V. Me. Pul= 0,63± 0,10m/s; VTI Pul= 0,13± 0,02m; TA Pul= 70,97± 18,87ms; TE Pul= 203,70± 28,98ms. Em apenas três animais observou-se regurgitação pulmonar. Alguns parâmetros apresentaram correlação negativa com a variável freqüência cardíaca (VTI AO, TE AO, VTI Pul, TA Pul, TE Pul); outros correlação positiva com a variável peso (VTI AO, TA AO, TE AO, VTI Pul, TE Pul,) e não se observou influência da variável sexo na maioria dos parâmetros avaliados. Na comparação entre os dois fluxos, observaram-se V. Max. AO e V. Me. AO maiores que V. Max. Pul. e V. Me. Pul., respectivamente, VTI AO maior que VTI Pul, e TA AO menor que TA Pul.

A critical analysis of Doppler velocimetry in the differential diagnosis of malignant and benign ovarian masses

Objectives: To evaluate the intratumoral reliability of color Doppler parameters and the contribution of Doppler sonography to the gray-scale differential diagnosis of ovarian masses. Methods: An observational study was performed including 67 patients, 15 (22.4%) with malignant ovarian neoplasm and 52 (77.6%) with benign ovarian diseases. We performed the Doppler evaluation in two distinct vessels selected after decreasing the Doppler gain to sample only vessels with higher velocity flow. Doppler measurements were obtained from each identified vessel, and resistive index (RI), pulsatility index (PI), peak systolic velocity (PSV), and end-diastolic velocity (EDV) were measured. Intraclass coefficient of correlation (ICC), sensitivity, specificity, and potential improvement in gray-scale ultrasound performance were calculated. Results: The general ICC were 0.60 (95% CI 0.42- 0.73) for RI, 0.65 (95% CI 0.49- 0.77) for PI, 0.07 (95% CI- 0.17-0.30) for PSV, and 0.19 (95% CI -0.05-0.41) for EDV. The sensitivity and specificity were respectively 84.6% and 86.7% for RI, 69.2% and 93.3% for PI, 80.0% and 65.4% for gray-scale sonography, and 93.3% and 65.4% for gray-scale plus RI (p = 0.013). Conclusions: Gynecologists must be careful in interpreting results from Doppler evaluation of ovarian masses because PSV and EDV present poor intratumoral reliability. The lower RI value, evaluated in at least two distinct sites of the tumor, was able to improve the performance of gray-scale ultrasound in differential diagnosis of ovarian masses.

MULTILINE DOPPLER IMAGING OF MR SER IN HIGH STATE

Doppler images in Balmer, He I, He II and C II lines, and simultaneous I-band photometry of the polar MR Ser are presented and analyzed. The Balmer and Helium Doppler tomograms, of this bright polar at high mass transfer state show the emission from the accretion flow and the heated surface of the companion star. As a result of a comparison between the Doppler tomograms, the ionization structure of the flow could be constrained. The highest ionization region was found in the vicinity of the magnetospheric radius. Photoionization modeling of the accretion column indicates that the Balmer and Helium emission line production in this system can be explained only by the central soft X-ray illumination. The orbital ephemeris of MR Ser has been revised.

Normal Doppler velocimetry of renal vasculature in Persian cats

Renal diseases are common in older cats. Decreased renal blood flow may be the first sign of dysfunction and can be evaluated by Doppler ultrasound. But previous studies suggest that the resistive index (RI) has a low sensitivity for detecting renal disease. Doppler waveforms of renal and intrarenal arteries demonstrate decreased blood flow before there are any changes in the RI. The purpose of this study was to evaluate the normal Doppler flowmetrics parameters of renal arteries (RAs), interlobar arteries (IAs) and abdominal aorta (AO) in adult healthy, Persian cats. Twenty-five Persian cats (13 females and 12 males with mean age of 30 months and an age range 12-60 months) with normal clinical examinations and biochemical tests and normal systemic blood pressure were given B-mode ultrasonographies in order to exclude all nephropathies, including polycystic kidney disease. All measurements were performed on both kidneys. Both kidneys (n = 50) were examined by color mapping of the renal vasculature. Pulsed Doppler was used to examine both RAs, the IAs at cranial, middle and caudal sites, and the AO. The RI was calculated for all of the vessels. Early systolic acceleration (ESA) of RA and IA was obtained with Doppler spectral analysis. Furthermore, the ratio indices between RA/AO, and IA/RA velocities were calculated. The mean values of peak systolic velocity (PSV) and the diameter for AO were 53.17 +/- 13.46 cm/s and 0.38 +/- 0.08 cm, respectively. The mean RA diameter for all 50 kidneys was 0.15 +/- 0.02 cm. Considering the velocimetric values in both RAs, the mean PSV and RI that were obtained were 41.17 +/- 9.40 cm/s and 0.54 +/- 0.07. The RA had a mean ESA of 1.12 +/- 1.14 m/s(2) and the calculated upper limit of the reference value was 3.40 m/s(2). The mean renal-aortic ratio was 0.828 +/- 0.296. The IA showed PSV and RI values of 32.16 +/- 9.33 cm/s and 0.52 +/- 0.06, respectively. The mean ESA of all IAs was 0.73 +/- 0.61 m/s(2). The calculated upper limit of the reference value was 2.0 m/s(2). The mean renal-interlobar artery ratio was 1.45 +/- 0.57. The RI values obtained in this study were similar to values reported in the literature. Some conditions that lead to a decrease in compliance and to an increase in vascular resistance can affect the Doppler spectral waveforms without changes in RI. To our knowledge, there are no studies that were directed toward to the normal ESA values of the renal vasculature in Persian cats. This study introduced a new ratio between the PSV of the RA and the IA. This index was developed based on the well-known effects of Doppler on the detection of stenosis, regardless of the cause. Further studies are necessary to verify the hemodynamic behavior of this index under pathological conditions in cats as well as the effect of aging, nephropathies and systemic pressure on Doppler velocimetric parameters. (C) 2010 ISFM and AAFP. Published by Elsevier Ltd. All rights reserved.

The systematic use of intraoperative vascular Doppler ultrasound during microsurgical subinguinal varicocelectomy improves precise identification and preservation of testicular blood supply

Objective: To evaluate the impact of systematic use of intraoperative Doppler ultrasound during microsurgical subinguinal varicocele repair. Design: Prospective clinical study. Setting: Andrology laboratory and male infertility section of the urology department of a tertiary care hospital. Patient(s): Two hundred and thirteen men with clinical varicocele. Intervention(s): Subinguinal microsurgical varicocele ligation using an intraoperative vascular Doppler flow detector. Main Outcome Measure(s): Number of veins ligated, lymphatic spared, arteries identified or accidentally ligated. Result(s): A statistically significant greater number of arteries were identified and preserved when intraoperative vascular Doppler was used. In addition, the average number of internal spermatic veins ligated was statistically significantly greater in the same group. Accidental artery ligation occurred in two cases (1.1%) in which the Doppler was not applied. There was no statistically significant difference in number of lymphatics spared between groups. Conclusion(s): Our findings showed that concomitant use of intraoperative vascular Doppler during microsurgical varicocelectomy allows more arterial branches to be preserved, and more internal spermatic veins are likely to be ligated. This device should be considered an attractive tool to improve surgical outcomes and safety. (Fertil Steril (R) 2010; 93: 2396-9. (C)2010 by American Society for Reproductive Medicine.)

Cardiac troponin T as a biochemical marker of cardiac dysfunction and ductus venosus Doppler velocimetry

Objectives: The aim of this study was to determine the correlation between ductus venosus (DV) Doppler velocimetry and fetal cardiac troponin T (cTnT). Study design: Between March 2007 and March 2008, 89 high-risk pregnancies were prospectively studied. All patients delivered by cesarean section and the Doppler exams were performed on the same day. Multiple regression included the following variables: maternial age, parity, hypertension, diabetes, gestational age at delivery, umbilical artery (UA) S/D ratio, diagnosis of absent or reversed end-diastolic flow velocity (AREDV) in the UA, middle cerebral artery (MCA) pulsatility index (131), and DV pulsatility index for veins (PIV). Immediately after delivery, UA blood samples were obtained for the measurement of pH and cTnT levels. Statistical analysis included the Kruskal-Wallis test and multiple regressions. Results: The results showed a cTnT concentration at birth >0.05 ng/ml in nine (81.8%) of AREDV cases, a proportion significantly higher than that observed in normal UA S/D ratio and UA S/D ratio >p95 with positive diastolic blood flow (7.7 and 23.1%, respectively, p < 0.001). A positive correlation Was found between abnormal DV-PIV and elevated cTnT levels in the UA. Multiple regression identified DV-PIV and a diagnosis of AREDV as independent factors associated with abnormal fetal cTnT levels (p < 0.0001, F(2.86) = 63.5, R = 0.7722). Conclusion: DV-PIV was significantly correlated with fetal cTnT concentrations at delivery. AREDV and abnormal DV flow represent severe cardiac compromise, with increased systemic venous pressure, and a rise in right ventricular afterload, demonstrated by myocardial damage and elevated fetal cTnT. (C) 2009 Elsevier Ireland Ltd. All rights reserved.