Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 39
Filtrar
Más filtros

País/Región como asunto
Tipo del documento
País de afiliación
Intervalo de año de publicación
1.
Am J Obstet Gynecol ; 225(3): 308.e1-308.e14, 2021 09.
Artículo en Inglés | MEDLINE | ID: mdl-33823150

RESUMEN

BACKGROUND: In women with late preterm preeclampsia, the optimal time for delivery remains a controversial topic, because of the fine balance between the maternal benefits from early delivery and the risks for prematurity. It remains challenging to define prognostic markers to identify women at highest risk for complications, in which case a selective, planned delivery may reduce the adverse maternal and perinatal outcomes. OBJECTIVE: This trial aimed to determine whether using an algorithm based on the maternal levels of placental growth factor in women with late preterm preeclampsia to evaluate the best time for delivery reduced the progression to preeclampsia with severe features without increasing the adverse perinatal outcomes. STUDY DESIGN: This parallel-group, open-label, multicenter, randomized controlled trial was conducted at 7 maternity units across Spain. We compared selective planned deliveries based on maternal levels of placental growth factor at admission (revealed group) and expectant management under usual care (concealed group) with individual randomization in singleton pregnancies with late preterm preeclampsia from 34 to 36+6 weeks' gestation. The coprimary maternal outcome was the progression to preeclampsia with severe features. The coprimary neonatal outcome was morbidity at infant hospital discharge with a noninferiority hypothesis (noninferiority margin of 10% difference in incidence). Analyses were conducted according to intention-to-treat. RESULTS: Between January 1, 2016, and December 31, 2019, 178 women were recruited. Of those women, 88 were assigned to the revealed group and 90 were assigned to the concealed group. The data analysis was performed before the completion of the required sample size. The proportion of women with progression to preeclampsia with severe features was significantly lower in the revealed group than in the concealed group (adjusted relative risk, 0.5; 95% confidence interval, 0.33-0.76; P=.001). The proportion of infants with neonatal morbidity was not significantly different between groups (adjusted relative risk, 0.77; 95% confidence interval, 0.39-1.53; P=.45). CONCLUSION: There is evidence to suggest that the use of an algorithm based on placental growth factor levels in women with late preterm preeclampsia leads to a lower rate of progression to preeclampsia with severe features and reduces maternal complications without worsening the neonatal outcomes. This trade-off should be discussed with women with late preterm preeclampsia to allow shared decision making about the timing of delivery.


Asunto(s)
Factor de Crecimiento Placentario/sangre , Preeclampsia/sangre , Adulto , Algoritmos , Biomarcadores/sangre , Progresión de la Enfermedad , Femenino , Humanos , Recién Nacido , Embarazo , Pronóstico , Espera Vigilante
2.
Sensors (Basel) ; 20(16)2020 Aug 05.
Artículo en Inglés | MEDLINE | ID: mdl-32764345

RESUMEN

This paper presents the results of the comparison between a proposed Fourth Order Elastic Constants (FOECs) nonlinear model defined in the sense of Landau's theory, and the two most contrasted hyperelastic models in the literature, Mooney-Rivlin, and Ogden models. A mechanical testing protocol is developed to investigate the large-strain response of ex vivo cervical tissue samples in uniaxial tension in its two principal anatomical locations, the epithelial and connective layers. The final aim of this work is to compare the reconstructed shear modulus of the epithelial and connective layers of cervical tissue. According to the obtained results, the nonlinear parameter A from the proposed FOEC model could be an important biomarker in cervical tissue diagnosis. In addition, the calculated shear modulus depended on the anatomical location of the cervical tissue (µepithelial = 1.29 ± 0.15 MPa, and µconnective = 3.60 ± 0.63 MPa).


Asunto(s)
Dinámicas no Lineales , Enfermedades del Cuello del Útero , Elasticidad , Femenino , Humanos , Estrés Mecánico , Enfermedades del Cuello del Útero/diagnóstico
3.
Sensors (Basel) ; 20(8)2020 Apr 22.
Artículo en Inglés | MEDLINE | ID: mdl-32331295

RESUMEN

The adoption of multiscale approaches by the biomechanical community has caused a major improvement in quality in the mechanical characterization of soft tissues. The recent developments in elastography techniques are enabling in vivo and non-invasive quantification of tissues' mechanical properties. Elastic changes in a tissue are associated with a broad spectrum of pathologies, which stems from the tissue microstructure, histology and biochemistry. This knowledge is combined with research evidence to provide a powerful diagnostic range of highly prevalent pathologies, from birth and labor disorders (prematurity, induction failures, etc.), to solid tumors (e.g., prostate, cervix, breast, melanoma) and liver fibrosis, just to name a few. This review aims to elucidate the potential of viscous and nonlinear elastic parameters as conceivable diagnostic mechanical biomarkers. First, by providing an insight into the classic role of soft tissue microstructure in linear elasticity; secondly, by understanding how viscosity and nonlinearity could enhance the current diagnosis in elastography; and finally, by compounding preliminary investigations of those elastography parameters within different technologies. In conclusion, evidence of the diagnostic capability of elastic parameters beyond linear stiffness is gaining momentum as a result of the technological and imaging developments in the field of biomechanics.


Asunto(s)
Diagnóstico por Imagen de Elasticidad/métodos , Viscosidad , Fenómenos Biomecánicos , Humanos
4.
J Obstet Gynaecol ; 40(6): 767-771, 2020 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-32648534

RESUMEN

To assess the opinion and the level of satisfaction of patients concerning analgesia during external cephalic version (ECV), we present the results of a survey of 120 women undergoing ECV at term during a randomised controlled trial (July 2012 to February 2013) comparing remifentanil and nitrous oxide. Overall, 110 (91.7%) women said they would repeat the procedure and 111 (92.5%) that they would recommend it to another pregnant woman, with no significant differences by type of analgesia. The administration and sense of comfort were rated better in the remifentanil group (p < .01). In conclusion, the use of analgesia during ECV is associated with a high rate of willingness among women to repeat the procedure and recommend it to other pregnant women.Impact statementWhat is already known on this subject? ECV is commonly a painful manoeuvre for the woman. This pain triggers maternal reactive abdominal muscle contraction and involuntary abdominal tensing, reducing the likelihood of successful version and causing some women to reject the technique.What do the results of this study add? The use of analgesia during ECV is associated with a high rate of willingness among women to repeat the procedure and recommend it to other pregnant women. The sense of comfort during ECV was also significantly better in the remifentanil group, probably because of its greater analgesic power and greater comfort during its administration.What are the implications of these findings for clinical practice and/or further research? ECV should be carried out under analgesia, when available, not only to decrease pain but also to encourage wider adoption of the technique and enable more women to benefit from it.


Asunto(s)
Analgesia Obstétrica/psicología , Manejo del Dolor/psicología , Dolor Asociado a Procedimientos Médicos/psicología , Satisfacción del Paciente/estadística & datos numéricos , Versión Fetal/psicología , Adulto , Analgesia Obstétrica/métodos , Analgésicos no Narcóticos/uso terapéutico , Analgésicos Opioides/uso terapéutico , Presentación de Nalgas/terapia , Femenino , Humanos , Óxido Nitroso/uso terapéutico , Manejo del Dolor/métodos , Dimensión del Dolor , Dolor Asociado a Procedimientos Médicos/tratamiento farmacológico , Dolor Asociado a Procedimientos Médicos/etiología , Embarazo , Remifentanilo/uso terapéutico , Nacimiento a Término/psicología , Versión Fetal/efectos adversos
5.
J Perinat Med ; 47(6): 625-630, 2019 Aug 27.
Artículo en Inglés | MEDLINE | ID: mdl-31141492

RESUMEN

Background Obesity in pregnancy is increasing worldwide, reaching epidemic proportions in many countries and frequently creating challenges for obstetricians. We conducted this study to assess the effects of maternal obesity on maternal and perinatal outcomes. Methods A historical cohort study was performed on 16,609 women who delivered singleton babies in a 5-year period (2013-2017). Data were retrieved from the Cruces Perinatal Database (CPD) and only women whose prepregnancy body mass index (BMI) was known were included. Women were categorized according to the World Health Organization (WHO) classification: normal weight (BMI 20-24.9 kg/m2) and obesity (BMI ≥ 30 kg/m2). Obstetric, perinatal and neonatal outcomes were compared, and adjusted odds ratios (aORs) and 95% confidence intervals (95% CIs) were calculated using the normal-weight group as the reference. Results Compared to women of normal weight (n = 9778), obese women (n = 2207) had a higher risk of preeclampsia (aOR 2.199, 95% CI: 1.46-3.29), rectovaginal group B streptococcus colonization (aOR 1.299, 95% CI: 1.14-1.47), induction of labor (aOR 1.593, 95% CI: 1.44-1.75), cesarean section (aOR 2.755, 95% CI: 2.46-3.08), cesarean section in women with a history of cesarean delivery (aOR 1.409, 95% CI: 1.03-1.92), fetal weight ≥4000 g (aOR 2.090, 95% CI: 1.803-2.422) and admission to the neonatal intensive care unit (NICU) (aOR 1.341, 95% CI: 1.12-1.59). No association was found with preterm birth (aOR 0.936, 95% CI: 0.77-1.13), stillbirth (aOR 0.921, 95% CI: 0.41-2.02) or neonatal mortality (aOR 2.205, 95% CI: 0.86-5.62). Conclusion Maternal obesity is associated with a higher risk of adverse pregnancy and perinatal outcomes. Pregnancy in this population of women should be considered and managed as high risk.


Asunto(s)
Cesárea/estadística & datos numéricos , Diabetes Gestacional/epidemiología , Obesidad Materna , Preeclampsia/epidemiología , Complicaciones del Embarazo , Nacimiento Prematuro/epidemiología , Adulto , Índice de Masa Corporal , Femenino , Humanos , Lactante , Mortalidad Infantil , Recién Nacido , Edad Materna , Obesidad Materna/diagnóstico , Obesidad Materna/epidemiología , Embarazo , Complicaciones del Embarazo/diagnóstico , Complicaciones del Embarazo/epidemiología , Resultado del Embarazo/epidemiología , Embarazo de Alto Riesgo , España/epidemiología , Mortinato/epidemiología
6.
Sensors (Basel) ; 19(15)2019 Jul 25.
Artículo en Inglés | MEDLINE | ID: mdl-31349721

RESUMEN

The reconstruction of viscous properties of soft tissues, and more specifically, of cervical tissue is a challenging problem. In this paper, a new method is proposed to reconstruct the viscoelastic parameters of cervical tissue-mimicking phantoms by a Torsional Wave Elastography (TWE) technique. The reconstruction method, based on a Probabilistic Inverse Problem (PIP) approach, is presented and experimentally validated against Shear Wave Elastography (SWE). The anatomy of the cervical tissue has been mimicked by means of a two-layer gelatine phantom that simulates the epithelial and connective layers. Five ad hoc oil-in-gelatine phantoms were fabricated at different proportion to test the new reconstruction technique. The PIP approach was used for reconstructing the Kelvin-Voigt (KV) viscoelastic parameters by comparing the measurements obtained from the TWE technique with the synthetic signals from a Finite Difference Time Domain (FDTD) KV wave propagation model. Additionally, SWE tests were realized in order to characterize the viscoelastic properties of each batch of gelatine. Finally, validation was carried out by comparing the KV parameters inferred from the PIP with those reconstructed from the shear wave dispersion curve obtained from the SWE measurements. In order to test the degree of agreement between both techniques, a Student's T-test and a Pearson's correlation study were performed. The results indicate that the proposed method is able to reconstruct the KV viscoelastic properties of the cervical tissue, for both the epithelial and connective layers, as well as the thickness of the first layer with acceptable accuracy.


Asunto(s)
Cuello del Útero/diagnóstico por imagen , Diagnóstico por Imagen de Elasticidad/métodos , Fantasmas de Imagen , Viscosidad , Adulto , Fenómenos Biomecánicos , Cuello del Útero/fisiología , Elasticidad , Femenino , Gelatina/química , Humanos , Embarazo
7.
Sensors (Basel) ; 19(15)2019 Jul 24.
Artículo en Inglés | MEDLINE | ID: mdl-31344796

RESUMEN

A torsional wave (TW) sensor prototype was employed to quantify stiffness of the cervix in pregnant women. A cross-sectional study in a total of 18 women between 16 weeks and 35 weeks + 5 days of gestation was performed. The potential of TW technique to assess cervical ripening was evaluated by the measurement of stiffness related to gestational age and cervical length. Statistically significant correlations were found between cervical stiffness and gestational age ( R 2 = 0.370 , p = 0.0074 , using 1 kHz waves and R 2 = 0.445 , p = 0.0250 , using 1.5 kHz waves). A uniform decrease in stiffness of the cervical tissue was confirmed to happen during the complete gestation. There was no significant correlation between stiffness and cervical length. A stronger association between gestational age and cervical stiffness was found compared to gestational age and cervical length correlation. As a conclusion, TW technique is a feasible approach to objectively quantify the decrease of cervical stiffness related to gestational age. Further research is required to evaluate the application of TW technique in obstetric evaluations, such as prediction of preterm delivery and labor induction failure.


Asunto(s)
Cuello del Útero/diagnóstico por imagen , Diagnóstico por Imagen de Elasticidad/métodos , Anomalía Torsional/diagnóstico por imagen , Adulto , Maduración Cervical/fisiología , Cuello del Útero/fisiopatología , Estudios Transversales , Elasticidad , Femenino , Edad Gestacional , Humanos , Trabajo de Parto Inducido , Embarazo , Anomalía Torsional/fisiopatología
8.
Sensors (Basel) ; 18(9)2018 Sep 07.
Artículo en Inglés | MEDLINE | ID: mdl-30205422

RESUMEN

Optimizing an experimental design is a complex task when a model is required for indirect reconstruction of physical parameters from the sensor readings. In this work, a formulation is proposed to unify the probabilistic reconstruction of mechanical parameters and an optimization problem. An information-theoretic framework combined with a new metric of information density is formulated providing several comparative advantages: (i) a straightforward way to extend the formulation to incorporate additional concurrent models, as well as new unknowns such as experimental design parameters in a probabilistic way; (ii) the model causality required by Bayes' theorem is overridden, allowing generalization of contingent models; and (iii) a simpler formulation that avoids the characteristic complex denominator of Bayes' theorem when reconstructing model parameters. The first step allows the solving of multiple-model reconstructions. Further extensions could be easily extracted, such as robust model reconstruction, or adding alternative dimensions to the problem to accommodate future needs.

9.
Ultraschall Med ; 38(4): 395-402, 2017 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-26251994

RESUMEN

Purpose To explore the feasibility of transient elastography (TE) to quantify cervical stiffness changes during normal pregnancy and its spatial variability. Materials and Methods TE was used to quantify the cervical stiffness in four anatomical regions. 42 women between 17 and 43 years of age and at 6 - 41 weeks of gestation were studied. The stiffness was related to gestational age at the time of examination, interval from ultrasound examination to delivery and cervical length to evaluate the potential of TE to assess cervical ripening. In addition, a sensitivity analysis based on Cronbach's alpha coefficient was carried out to assess the concordance between inter/intra-operator measurements. Results There were significant correlations between cervical stiffness measured in the four regions with gestational age and the remaining time for delivery. Results confirm stiffness variability within the cervix. No significant association was found between cervical length and stiffness in the four ROIs. Associations between gestational age and remaining time for delivery with cervical length present weaker correlations than with cervical stiffness. The external part of the cervix was significantly softer than the internal one, and these stiffness values vary significantly in the anterior compared to the posterior cervix. The measurements taken by the same and by two different observers for different regions in the cervix were reliable and reproducible. Conclusion It is feasible to objectively quantify the decrease of cervical stiffness correlated to gestational age. Transient elastography is a valuable promising tool to provide additional information on the process of cervical effacement to that obtained from digital examination and conventional ultrasound. Further studies are needed to assess the feasibility of the technique in obstetric clinical applications, such as prediction of preterm birth or success in labor induction.


Asunto(s)
Maduración Cervical , Cuello del Útero , Diagnóstico por Imagen de Elasticidad , Adolescente , Adulto , Cuello del Útero/diagnóstico por imagen , Femenino , Edad Gestacional , Humanos , Trabajo de Parto Inducido , Embarazo , Nacimiento Prematuro , Adulto Joven
10.
Sensors (Basel) ; 17(6)2017 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-28617353

RESUMEN

Torsion mechanical waves have the capability to characterize shear stiffness moduli of soft tissue. Under this hypothesis, a computational methodology is proposed to design and optimize a piezoelectrics-based transmitter and receiver to generate and measure the response of torsional ultrasonic waves. The procedure employed is divided into two steps: (i) a finite element method (FEM) is developed to obtain a transmitted and received waveform as well as a resonance frequency of a previous geometry validated with a semi-analytical simplified model and (ii) a probabilistic optimality criteria of the design based on inverse problem from the estimation of robust probability of detection (RPOD) to maximize the detection of the pathology defined in terms of changes of shear stiffness. This study collects different options of design in two separated models, in transmission and contact, respectively. The main contribution of this work describes a framework to establish such as forward, inverse and optimization procedures to choose a set of appropriate parameters of a transducer. This methodological framework may be generalizable for other different applications.


Asunto(s)
Ultrasonografía , Análisis de Elementos Finitos , Transductores , Vibración
11.
Sensors (Basel) ; 17(9)2017 Sep 11.
Artículo en Inglés | MEDLINE | ID: mdl-28891995

RESUMEN

A novel torsional wave sensor designed to characterize mechanical properties of soft tissues is presented in this work. Elastography is a widely used technique since the 1990s to map tissue stiffness. Moreover, quantitative elastography uses the velocity of shear waves to achieve the shear stiffness. This technique exhibits significant limitations caused by the difficulty of the separation between longitudinal and shear waves and the pressure applied while measuring. To overcome these drawbacks, the proposed torsional wave sensor can isolate a pure shear wave, avoiding the possibility of multiple wave interference. It comprises a rotational actuator disk and a piezoceramic receiver ring circumferentially aligned. Both allow the transmission of shear waves that interact with the tissue before being received. Experimental tests are performed using tissue mimicking phantoms and cervical tissues. One contribution is a sensor sensitivity study that has been conducted to evaluate the robustness of the new proposed torsional wave elastography (TWE) technique. The variables object of the study are both the applied pressure and the angle of incidence sensor-phantom. The other contribution consists of a cervical tissue characterization. To this end, three rheological models have fit the experimental data and a static independent testing method has been performed. The proposed methodology permits the reconstruction of the mechanical constants from the propagated shear wave, providing a proof of principle and warranting further studies to confirm the validity of the results.


Asunto(s)
Cuello , Diagnóstico por Imagen de Elasticidad , Fantasmas de Imagen , Reología
12.
Acta Obstet Gynecol Scand ; 95(5): 547-54, 2016 May.
Artículo en Inglés | MEDLINE | ID: mdl-26830687

RESUMEN

INTRODUCTION: Our objective was to compare the effect of two pain relief methods (remifentanil vs. nitrous oxide) on the success rate of external cephalic version. MATERIAL AND METHODS: We conducted a randomized open label parallel-group controlled single-center clinical trial with sequential design, at Cruces University Hospital, Spain. Singleton pregnancies in noncephalic presentation at term that were referred for external cephalic version were assigned according to a balanced (1:1) restricted randomization scheme to analgesic treatment with remifentanil or nitrous oxide during the procedure. The primary endpoint was external cephalic version success rate. Secondary endpoints were adverse event rate, degree of pain, cesarean rate and perinatal outcomes. RESULTS: The trial was stopped early after the second interim analysis due to a very low likelihood of finding substantial differences in efficacy (futility). The external cephalic version success rate was the same in the two arms (31/60, 51.7%) with 120 women recruited, 60 in each arm. The mean pain score was significantly lower in the remifentanil group (3.2 ± 2.4 vs. 6.0 ± 2.3; p < 0.01). No differences were found in external cephalic version-related complications. There was a trend toward a higher frequency of adverse effects in the remifentanil group (18.3% vs. 6.7%, p = 0.10), with a significantly higher incidence rate (21.7 events/100 women vs. 6.7 events/100 women with nitrous oxide, p = 0.03). All reported adverse events were mild and reversible. CONCLUSIONS: Remifentanil for analgesia decreased external cephalic version-related pain but did not increase the success rate of external cephalic version at term and appeared to be associated with an increased frequency of mild adverse effects.


Asunto(s)
Presentación de Nalgas , Dolor de Parto , Trabajo de Parto/efectos de los fármacos , Óxido Nitroso , Piperidinas , Adulto , Analgésicos/administración & dosificación , Analgésicos/efectos adversos , Presentación de Nalgas/diagnóstico , Presentación de Nalgas/fisiopatología , Cesárea/estadística & datos numéricos , Terminación Anticipada de los Ensayos Clínicos , Femenino , Humanos , Dolor de Parto/diagnóstico , Dolor de Parto/tratamiento farmacológico , Dolor de Parto/etiología , Dolor de Parto/fisiopatología , Óxido Nitroso/administración & dosificación , Óxido Nitroso/efectos adversos , Manejo del Dolor/métodos , Dimensión del Dolor/métodos , Piperidinas/administración & dosificación , Piperidinas/efectos adversos , Embarazo , Resultado del Embarazo , Remifentanilo , Resultado del Tratamiento
13.
Am J Obstet Gynecol ; 211(6): 665.e1-7, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-24949536

RESUMEN

OBJECTIVE: We sought to analyze whether maternal intravenous fluid therapy prior to external cephalic version (ECV) increases the amount of amniotic fluid and the success rate of the procedure. STUDY DESIGN: This was a prospective single-center cohort study of 200 women with a consecutive cohort of 100 pregnant women with a breech presentation at term who were administered intravenous fluid therapy with 2 L of hypotonic saline before the version attempt, compared to a control cohort of 100 pregnant women not given hydration treatment. RESULTS: The mean increase in the amniotic fluid index (AFI) after intravenous maternal hydration was 3.75 ± 2.71 cm. The amount of fluid before hydration was the only variable found to be associated with increases in amniotic fluid levels, both in absolute and relative terms (odds ratio, -0.21; 95% confidence interval, -0.37 to -0.05 and odds ratio, -4.62; 95% confidence interval, -6.17 to -3.06; P < .01, respectively). We did not observe any severe complications secondary to the intravenous fluid therapy. The ECV success rate was 43% in the study group compared to 47% in the control group (P = .67). The success rate was significantly lower the larger the relative increase in the AFI, although no correlation was found in absolute terms (χ(2) for linear trend = 0.03 and 0.34, respectively). CONCLUSION: Maternal intravenous fluid therapy with 2 L of hypotonic saline prior to ECV is an effective and safe technique for increasing the AFI. However, its use in ECV does not increase the success rate of the procedure.


Asunto(s)
Líquido Amniótico , Presentación de Nalgas/terapia , Fluidoterapia/métodos , Versión Fetal/métodos , Adulto , Estudios de Cohortes , Femenino , Humanos , Infusiones Intravenosas , Embarazo , Estudios Prospectivos , Resultado del Tratamiento
14.
J Perinat Med ; 41(6): 719-23, 2013 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-23924521

RESUMEN

OBJECTIVE: The objective of this study was to analyze the effect of using inhaled nitrous oxide (N2O) for analgesia in external cephalic version (ECV) at term on the success rate of the procedure, on pain, and on obstetric and perinatal outcomes. METHODS: A prospective comparative cohort study among 300 women with singleton pregnancy in breech presentation at term undergoing an ECV with inhaled N2O in a 50:50 mix with oxygen for analgesia and 150 ECVs with no analgesia. RESULTS: The success rate was 52.3% in the N2O cohort and 52.7% in the controls (P=0.94), whereas the median level of pain was statistically lower in women given N2O (median, 6; range, 4-7, vs. median, 7; range, 5-8; P<0.01). This improvement is mainly from a 49% decrease in severe pain. There were no significant differences in the rate of complications associated with the ECV, in the rate of cesarean sections, or in perinatal outcomes. Furthermore, there were no severe complications secondary to N2O inhalation. CONCLUSIONS: N2O inhalation at a concentration of 50% for analgesia during ECV decreases the level of severe pain experienced by women, appears to be safe both for mother and child, and has no influence on the success rate of ECV or the perinatal outcomes.


Asunto(s)
Analgesia Obstétrica/métodos , Presentación de Nalgas/terapia , Óxido Nitroso/administración & dosificación , Versión Fetal/métodos , Administración por Inhalación , Adulto , Estudios de Cohortes , Femenino , Humanos , Recién Nacido , Óxido Nitroso/efectos adversos , Manejo del Dolor/métodos , Embarazo , Resultado del Embarazo , Estudios Prospectivos , Resultado del Tratamiento
15.
Aust N Z J Obstet Gynaecol ; 52(1): 59-61, 2012 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-22141436

RESUMEN

AIM: To design a score based on clinical parameters to predict the outcome of external cephalic versions (ECVs) at term. MATERIALS AND METHODS: A two-phase study was conducted (analysis/design and prospective validation) regarding 1000 versions performed between March 2002 and November 2010. The variables considered in the score were selected based on the results of multiple logistic regression models and multiple correspondence analyses published by our group. The predictive capacity was estimated through the area under the ROC curve. RESULTS: The success rates for ECV in phases 1 and 2 were 52.2 and 51.2%, respectively, making the overall success rate 51.7%. The score was designed with the variables parity, placental location, breech variety and amount of amniotic fluid giving a value for each one. A clinical recommendation, based on the result of the score, was the estimated success rate with the 95% confidence interval. The predictive capacity of the score for the outcome of ECV at term was 70.1% (95% CI 66.9-73.4). CONCLUSIONS: A score composed of four easily measurable variables enabled us to predict the outcome of ECV at term.


Asunto(s)
Presentación de Nalgas , Sistemas de Apoyo a Decisiones Clínicas , Versión Fetal/métodos , Adulto , Femenino , Humanos , Modelos Logísticos , Embarazo , Complicaciones del Embarazo , Estudios Prospectivos , Curva ROC
16.
Sci Rep ; 12(1): 8354, 2022 05 19.
Artículo en Inglés | MEDLINE | ID: mdl-35589817

RESUMEN

Corneal mechanical changes are believed to occur before any visible structural alterations observed during routine clinical evaluation. This study proposed developing an elastography technique based on torsional waves (TWE) adapted to the specificities of the cornea. By measuring the displacements in the propagation plane perpendicular to the axis of the emitter, the effect of guided waves in plate-like media was proven negligible. Ex vivo experiments were carried out on porcine corneal samples considering a group of control and one group of alkali burn treatment ([Formula: see text]OH) that modified the mechanical properties. Phase speed was recovered as a function of intraocular pressure (IOP), and a Kelvin-Voigt rheological model was fitted to the dispersion curves to estimate viscoelastic parameters. A comparison with uniaxial tensile testing with thin-walled assumptions was also performed. Both shear elasticity and viscosity correlated positively with IOP, being the elasticity lower and the viscosity higher for the treated group. The viscoelastic parameters ranged from 21.33 to 63.17 kPa, and from 2.82 to 5.30 Pa s, for shear elasticity and viscosity, respectively. As far as the authors know, no other investigations have studied this mechanical plane under low strain ratios, typical of dynamic elastography in corneal tissue. TWE reflected mechanical properties changes after treatment, showing a high potential for clinical diagnosis due to its rapid performance time and paving the way for future in vivo studies.


Asunto(s)
Diagnóstico por Imagen de Elasticidad , Animales , Córnea/diagnóstico por imagen , Elasticidad , Diagnóstico por Imagen de Elasticidad/métodos , Porcinos , Tonometría Ocular , Viscosidad
17.
Ultrason Sonochem ; 88: 106096, 2022 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-35868210

RESUMEN

Sonocrystallization implies the application of ultrasound radiation to control the nucleation and crystal growth depending on the actuation time and intensity. Its application allows to induce nucleation at lower supersaturations than required under standard conditions. Although extended in inorganic and organic crystallization, it has been scarcely explored in protein crystallization. Now, that industrial protein crystallization is gaining momentum, the interest on new ways to control protein nucleation and crystal growth is advancing. In this work we present the development of a novel ultrasound bioreactor to study its influence on protein crystallization in agarose gel. Gel media minimize convention currents and sedimentation, favoring a more homogeneous and stable conditions to study the effect of an externally generated low energy ultrasonic irradiation on protein crystallization avoiding other undesired effects such as temperature increase, introduction of surfaces which induce nucleation, destructive cavitation phenomena, etc. In-depth statistical analysis of the results has shown that the impact of ultrasound in gel media on crystal size populations are statistically significant and reproducible.


Asunto(s)
Hidrogeles , Muramidasa , Ondas Ultrasónicas , Cristalización/métodos , Muramidasa/química , Proteínas/química
18.
J Perinat Med ; 39(4): 397-402, 2011 07.
Artículo en Inglés | MEDLINE | ID: mdl-21604996

RESUMEN

OBJECTIVE: To compare the efficacy and safety of two methods for induction of labor after previous cesarean section. METHODS: To compare 247 women with a previous cesarean section who were induced with a dinoprostone vaginal insert and 279 women with a previous cesarean section induced with oxytocin, between 2001 and 2008. We evaluated vaginal delivery rate, maternal morbidity and newborn morbidity and mortality. RESULTS: The overall rate of vaginal delivery was 65.2%. We did not find significant differences between induction with dinoprostone vaginal insert and oxytocin in the rate of cesarean section performed (35.6% vs. 34.1%, P=0.71). There were nine cases of uterine rupture (rate of 1.7%), of which four occurred with dinoprostone vaginal insert and five when using oxytocin (P=0.89). We found no significant differences in neonatal outcomes. CONCLUSIONS: Both tested methods appear to be equally safe and effective for induction of labor in women with a previous cesarean section.


Asunto(s)
Dinoprostona/administración & dosificación , Trabajo de Parto Inducido/métodos , Oxitócicos/administración & dosificación , Oxitocina/administración & dosificación , Parto Vaginal Después de Cesárea/métodos , Administración Intravaginal , Adulto , Dinoprostona/efectos adversos , Femenino , Humanos , Recién Nacido , Infusiones Intravenosas , Trabajo de Parto Inducido/efectos adversos , Masculino , Oxitócicos/efectos adversos , Oxitocina/efectos adversos , Embarazo , Resultado del Embarazo , Estudios Retrospectivos , Resultado del Tratamiento , Parto Vaginal Después de Cesárea/efectos adversos
19.
Fetal Diagn Ther ; 29(4): 287-95, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-21196702

RESUMEN

INTRODUCTION: Second-trimester fetal screening for congenital heart defects (CHD) included in routine obstetric care provides relevant information for decision making. The aim of this study was to describe the clinical practice of prenatal detection of CHD in terms of the process and results. METHODS: The characteristics and results of ultrasound screening for major CHD were documented using data provided by hospitals for a national survey in Spain over the period of 2004-2006. Sixty-seven percent of eligible centers (56/83), covering 36% of total births nationwide, responded to the survey; 33 of these returned complete data regarding the screening results. RESULTS: The number of major CHD occurring in the centers which provided data with results of screening was 1,060. The overall prenatal detection rate of major CHD was 65.7% (95% CI 57.8-74.7), but the detection rate in the routine second-trimester scan was 52.6% (95% CI 45.6-60.8). In 61% of these cases the parents chose to terminate the pregnancy. Two independent predictors of increased detection by center were identified: first, the uniformity and systematic character of the examination of the heart showing at least the 4-chamber view and outflow tracts (prevalence ratio 1.3, 95% CI 1.0-1.8) and second, the local availability of specialists in fetal echocardiography (prevalence ratio 1.4, 95% CI 1.1-1.9). CONCLUSIONS: The detection of major CHD in the first half of pregnancy has an important impact on parental decision making. The prenatal screening program for CHD should be globally strengthened in terms of qualifications and methodological approaches. To improve its performance locally, close collaboration with fetal heart specialists should be promoted.


Asunto(s)
Cardiopatías Congénitas/diagnóstico por imagen , Cardiopatías Congénitas/embriología , Pautas de la Práctica en Medicina , Ultrasonografía Prenatal , Femenino , Edad Gestacional , Encuestas de Atención de la Salud , Cardiopatías Congénitas/epidemiología , Humanos , Embarazo , España , Encuestas y Cuestionarios , Ultrasonografía Prenatal/métodos , Ultrasonografía Prenatal/estadística & datos numéricos
20.
Materials (Basel) ; 14(9)2021 Apr 29.
Artículo en Inglés | MEDLINE | ID: mdl-33946632

RESUMEN

Mechanical compatibility with the human dentin is a considerable issue when fabricating dental fiber posts. To this purpose, this study introduces a new method of fabricating compatible dental posts using braiding techniques of thermoplastic fibers (matrix) with glass fibers (reinforcement). Fifty fiber-reinforced composite (FRC) posts of thermoplastic yarns polypropylene (PP) braided with continuous filaments glass fibers (GFs) for reinforcement, varying in fiber volume fraction (FVF), and core types are fabricated and tested. Posts are performed using a braiding machine, and braids are placed in an aluminum mold. The filled mold is playced inside an oven at the melting temperature of the polypropylene to produce the final post's shape. An ultrasonic test is conducted to measure the shear modulus and Young's modulus of FRC post specimens by measuring the velocities of both the P-wave and S-wave. In order to ensure the accuracy of the measurements, each sample is measured three times, and then the means and standard deviations of each sample are calculated before analyzing the test results using the means of two steps, namely, clustering and comparing the P and R² values of each cluster, which revealed that FVF, fiber mass, and core type of the specimen had a significant effect on the resulted Young's and shear modulus. The results indicate that the proposed method can fabricate competitive dental posts with regard to different fabricating variables. The samples show Young's modulus ranges of from 10.08 GPa to 31.83 GPa. The following tested hypothesis is supported: the braiding technique of thermoplastic fibers with glass fibers will improve the mechanical compatibility of the resulting posts (ex vivo).

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA