Browsing by Author "Carvajal, Cristóbal"

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    Consecuencias hemodinámicas y respiratorias del síndrome compartimental abdominal en un modelo experimental
    (2012) Díaz, Franco; Donso, Alejandro; Carvajal, Cristóbal; Salomón, Tatiana; Torres, María Fernanda; Erranz, Benjamín; Cruces, Pablo
    Introducción: El síndrome compartimental abdominal (SCA) es una entidad grave, de escaso reporte en población pediátrica por una inadecuada alerta y reconocimiento. Puede ser originado por causas médicas y quirúrgicas, presentando una elevada mortalidad. Objetivo: Determinar la magnitud de las consecuencias hemodinámicas y respiratorias iniciales desencadenadas por la inducción de un SCA en un modelo experimental. Método: Doce cerdos anestesiados (4,8 ± 0,1 kg). El SCA fue inducido con instilación de solución coloide en cavidad peritoneal para obtener una presión intra-abdominal (PIA) de 25 ± 5 mmHg. En condiciones basales y posterior a inducción del SCA se realizó monitorización hemodinámica convencional y termodilución transpulmonar. Paralelamente se midió gasometría arterial y análisis de mecánica pulmonar. Resultados: Hubo una reducción del gasto cardíaco en 16% (5,19 ± 0,33 a 4,34 ± 0,28 l/min/m2, p = 0,01) y de la presión de perfusión abdominal en 20% (72,3 ± 3,2 a 57,3 ± 4,0 mmHg, p < 0,001) sin cambios en frecuencia cardiaca, presión arterial y venosa central. Además ocurrió un deterioro de la compliance del sistema respiratorio cercana al 50% (1,28 ± 0,09 a 0,62 ± 0,04 ml/cmH2O/kg, p = 0,002) asociado a un incremento significativo en las presiones intratorácicas y disminución leve de la oxigenación. Discusión: En este modelo experimental se pudo apreciar el desarrollo temprano de disfunción hemodinámica y pulmonar. Se evidenció una reducción de gasto cardiaco no detectado por la monitorización convencional y un deterioro substancial de la mecánica pulmonar, propia de una enfermedad restrictiva, asociado a alteraciones leves del intercambio gaseoso. Creemos que es fundamental monitorizar la PIA en pacientes predispuestos a desarrollar un SCA, más aún ante empeoramiento de disfunciones orgánicas dado que la hipotensión e hipoxemia grave son signos tardíos de esta complicación.
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    Decreased lung compliance increases preload dynamic tests in a pediatric acute lung injury model
    (Sociedad Chilena de Pediatría. Publicado por Elsevier España, S.L.U., 2015) Erranz, Benjamín; Díaz, Franco; Donoso, Alejandro; Salomón, Tatiana; Carvajal, Cristóbal; Torres, María Fernanda; Cruces, Pablo
    BACKGROUND: Preload dynamic tests, pulse pressure variation (PPV) and stroke volume variation (SVV) have emerged as powerful tools to predict response to fluid administration. The influence of factors other than preload in dynamic preload test is currently poorly understood in pediatrics. The aim of our study was to assess the effect of tidal volume (VT) on PPV and SVV in the context of normal and reduced lung compliance in a piglet model. MATERIAL AND METHOD: Twenty large-white piglets (5.2±0.4kg) were anesthetized, paralyzed and monitored with pulse contour analysis. PPV and SVV were recorded during mechanical ventilation with a VT of 6 and 12mL/kg (low and high VT, respectively), both before and after tracheal instillation of polysorbate 20. RESULTS: Before acute lung injury (ALI) induction, modifications of VT did not significantly change PPV and SVV readings. After ALI, PPV and SVV were significantly greater during ventilation with a high VT compared to a low VT (PPV increased from 8.9±1.2 to 12.4±1.1%, and SVV from 8.5±1.0 to 12.7±1.2%, both P<0.01). CONCLUSIONS: This study found that a high VT and reduced lung compliance due to ALI increase preload dynamic tests, with a greater influence of the latter. In subjects with ALI, lung compliance should be considered when interpreting the preload dynamic tests.
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    Diferencia veno-arterial de dióxido de carbono como predictor de gasto cardiaco disminuido en modelo pediátrico experimental
    (Sociedad Medica de Santiago, 2012) Díaz, Franco; Donoso, Alejandro; Carvajal, Cristóbal; Salomón, Tatiana; Torres, María; Erranz, Benjamín; Cruces, Pablo
    Background: Cardiac output (CO) measurement is not a standard of care for critically ill children, but it can be estimated by indirect methods such as veno-arterial pCO2 difference (ΔVACO2). Aim: To determine the correlation between CO and ΔVACO2 and evaluate the usefulness of ΔVACO2 in the diagnosis of low CO in an experimental pediatric model. Materials and Methods: Thirty piglets weighing 4.8 ± 0.35 kg were anesthetized and monitored with transpulmonary thermodilution. Lung injury was induced with tracheal instillation of Tween 20®. Serial measurements of central venous and arterial blood gases, as well as CO, were obtained at baseline, 1, 2 and 4 h after lung injury induction. Low cardiac output (LCO) was defined as CO lower than 2.5 Llminlm2. Results: There was an inverse correlation between CO and ΔVACO2 (r = -0.36, p < 0.01). ΔVACO2 was 14 ± 8 mmHg in LCO state and 8 ± 6 mmHg when this condition was not present (p < 0.01). Area under the receiver operating characteristic (ROC) curves of ΔVACO2 and LCO state was 0.78 (0.68-0.86). The best cut-point was 8.9 mmHg to determine LCO with a sensibility 0.78, specificity 0.7, positive predictive value 0.27 and negative predictive value 0.96. Conclusions: In this model there was an inverse correlation between ΔVACO2 and CO. The best cutoff value to discard LCO was ΔVACO2 of 8.9 mmHg, indicating that under this value the presence of LCO is very unlikely.
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    Fragilidad: en busca de herramientas de evaluación preoperatoria
    (2020) Vargas, Javiera; Gálvez, María de los Ángeles; Rojas, Mariana; Honorato, Macarena; Andrade, Maricarmen; Leyton, Patricio; Mardones, Gabriela; Morales, Julián; Pérsico, Daniela; Rojas, Fernanda; Moreno, Duby; Becker, Erika; Cavada, Gabriel; Carvajal, Cristóbal
    In the perioperative context, a frailty evaluation scale must consider certain characteristics such as validation, execution speed, simplicity, the capacity to measure multiple dimensions and not being dependent on a cognitive or physical test that could not be performed prior to surgery. The test should select patients that could benefit from interventions aimed to improve their postoperative outcomes. Aim: To validate two frailty evaluation scales for the perioperative period. Material and Methods: The Risk Analysis Index with local modifications (RAI-M) were applied to 201 patients aged 73 ± 7 years (49% women) and the Edmonton frailty scale were applied in 151 patients aged 73 ± 7 years (49% women) in the preoperative period. Their results were compared with the Rockwood frailty index. Results: The Edmonton frail scale showed adequate psychometric properties and assessed multiple dimensions through 8 of the 11 original questions, achieving a discrimination power over 80% compared to the Rockwood Index. The RAI- M, demonstrated solid psychometric properties with a tool that examines 4 dimensions of frailty through 15 questions and reviewing the presence of 11 medical comorbidities. This scale had a discrimination power greater than 85% and it was significantly associated with prolongation of the planned hospital stay and mortality. Conclusions: RAI-M is a short and easily administered scale, useful to detect frailty in the preoperative period
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    Mild hypothermia attenuates lung edema and plasma interleukin-1 beta in a rat mechanical ventilation-induced lung injury model
    (2011) Cruces, Pablo; Ronco, Ricardo; Erranz, Benjamín; Conget, Paulette; Carvajal, Cristóbal; Donoso, Alejandro; Díaz, Franco
    Recent data suggest that deep hypothermia has protective effects on experimental induced lung injury. It is not well known if these effects persist with mild hypothermia. The authors hypothesized that mild hypothermia may attenuate lung injury and decrease local and systemic proinflammatory cytokines in a rat model of injurious mechanical ventilation (MV). Twelve Sprague-Dawley male adult rats were anesthetized, intubated, and randomly allocated to normothermia group (37 degrees C) (NT) or mild hypothermia group (34 degrees C) (MH). After 2 hours of deleterious MV (peak inspiratory pressure [PIP] 40 cm H2O, zero end-expiratory pressure [ZEEP], and inspiratory fraction of oxygen [Fio(2)] 100%), arterial blood gases, lung gravimetry, and histological study were obtained. Protein content, interleukin (IL)-1 beta, and tumor necrosis factor (TNF)-alpha were measured in plasma and bronchoalveolar lavage (BAL) fluid. Subjects that underwent MH had a significant lower wet-to-dry lung weight ratio (8.32 +/- 0.28 vs. 10.8 +/- 0.49, P = .01), IL-1 beta plasma concentration (0.6 +/- 0.6 vs. 10.27 +/- 2.80 pg/mL, P = .0048) and Paco(2). There were no differences in terms of Pao(2), histological injury, or BAL protein content. In this model of injurious mechanical ventilation, subjects treated with mild hypothermia had less lung edema and lower plasma IL-1 beta. Some of known beneficial effects of deep hypothermia can be obtained with mild hypothermia.
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    Reduced PICU respiratory admissions during COVID-19
    (2020) Vásquez-Hoyos, Pablo; Díaz, Franco; Monteverde-Fernandez, Nicolás; Jaramillo-Bustamante, Juan Camilo; Carvajal, Cristóbal; Serra, Alberto; Karsies, Todd; Tellechea Rotta, Alexandre; González-Dambrauskas, Sebastián; LARed Network
    Background The COVID-19 pandemic reached the Southern Hemisphere in the autumn of 2020, thus coinciding with its expected annual viral respiratory season. The potential impact of national strategies aimed at mitigating COVID-19 during the pandemic on the incidence of other critical viral lower respiratory tract infections (LRTIs) in children is unknown. Methods We analysed admission data for LRTIs from 22 paediatric intensive care units (PICUs) in four countries, part of a large international Latin American registry of children with acute respiratory failure (Red Colaborativa Pediátrica de Latinoamérica [LARed Network]). Results Between January and August, there were 83% fewer PICU admissions for LRTIs in 2020 compared to the 2018/2019 average over the same period. Similar decreases were noted for PICU admissions due to respiratory syncytial virus and influenza (92% and 78%, respectively). Conclusion We observed a striking reduction in PICU admissions due to viral LRTIs over winter, during the COVID-19 pandemic in South America.
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    Variabilidad terapéutica en lactantes con bronquiolitis hospitalizados en unidades de cuidados intensivos latinoamericanas
    (2020) Serra, Jesús Alberto; González-Dambrauskas, Sebastián; Vásquez Hoyos, Pablo; Carvajal, Cristóbal; Donoso, Alejandro; Cruces, Pablo; Fernández, Alicia; Martínez Arroyo, Luis; Sarmiento, María Piedad; Nuñez, María José; Wegner Araya, Adriana; Jaramillo-Bustamante, Juan Camilo; Céspedes-Lesczinsky, Miguel; Jabornisky, Roberto; Monteverde-Fernández, Nicolás; Córdova, Tamara; Díaz, Franco
    Objetivo: describir las terapias utilizadas en lactantes con bronquiolitis aguda admitidos en 20 Unidades de Cuidados Intensivos (UCI) pediátricos miembros de LARed en 5 países latinoamericanos. Pacientes y Método: Estudio observacional retrospectivo, multicéntrico, de datos del Registro Latinoamericano de Falla Respiratoria Aguda Pediátrica. Se incluyeron niños menores de 2 años ingresados a UCI pediátrica por bronquiolitis aguda comunitaria entre mayo-septiembre 2017. Se recolectaron datos demográficos, clínicos, soporte respiratorio, terapias utilizadas y resultados clínicos. Se realizó análisis de subgrupos según ubicación geográfica, tipo financiación y presencia de academia. Resultados: Ingresaron al registro 1155 pacientes con falla respiratoria aguda. Seis casos fueron excluidos por no tener formulario completo. De los 1147 pacientes, 908 eran menores de 2 años. De ellos, 467 tuvieron diagnóstico de bronquiolitis aguda, correspondiendo a la principal causa de ingreso a UCI pediátrica por falla respiratoria aguda (51,4%). Las características demográficas y de gravedad entre los centros fueron similares. El soporte máximo respiratorio más frecuente fue cánula nasal de alto flujo (47%), seguido por ventilación mecánica no invasiva (26%) y ventilación mecánica invasiva (17%), con un coeficiente de variación (CV) amplio entre los centros. Hubo una gran dispersión en uso de terapias, siendo frecuente el uso de broncodilatadores, antibióticos y corticoides, con CV hasta 400%. El análisis de subgrupos mostró diferencias significativas en soporte respiratorio y tratamientos utilizados. Un paciente falleció en esta cohorte. Conclusión: Detectamos gran variabilidad en el soporte respiratorio y tratamientos entre UCI pediátricas latinoamericanas. Esta variabilidad no es explicada por disparidades demográficas ni clínicas. Esta heterogeneidad de tratamientos debería promover iniciativas colaborativas para disminuir la brecha entre la evidencia científica y la práctica asistencial.

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