Original article
Decreased lung compliance increases preload dynamic tests in a pediatric acute lung injury model
Una compliance pulmonar disminuida incrementa los test dinámicos de precarga en un modelo pediátrico de lesión pulmonar aguda
Benjamín Erranza, Franco Díazb, Alejandro Donosoc, Tatiana Salomónd, Cristóbal Carvajald, María Fernanda Torresd, Pablo Crucese,f,
Corresponding author
a Centro de Medicina Regenerativa, Facultad de Medicina, Clínica Alemana Universidad del Desarrollo, Santiago, Chile
b Department of Paediatric, Division of Pediatric Critical Care, University of Alabama at Birmingham, USA
c Unidad de Paciente Crítico Pediátrico, Hospital Clínico Metropolitano La Florida, Santiago, Chile
d Unidad de Cuidados Intensivos Pediátrica, Clínica Alemana de Santiago, Chile
e Unidad de Paciente Crítico Pediátrico, Hospital El Carmen de Maipú, Santiago, Chile
f Centro de Investigación de Medicina Veterinaria, Escuela de Medicina Veterinaria, Facultad de Ecología y Recursos Naturales, Universidad Andrés Bello, Santiago, Chile
Read
5278
Timeswas read the article
803
Total PDF
4475
Total HTML
Share statistics
array:24 [ "pii" => "S0370410615001850" "issn" => "03704106" "doi" => "10.1016/j.rchipe.2015.06.023" "estado" => "S300" "fechaPublicacion" => "2015-11-01" "aid" => "77" "copyright" => "Sociedad Chilena de Pediatría" "copyrightAnyo" => "2015" "documento" => "article" "crossmark" => 1 "licencia" => "http://creativecommons.org/licenses/by-nc-nd/4.0/" "subdocumento" => "fla" "cita" => "Rev Chil Ped. 2015;86:404-9" "abierto" => array:3 [ "ES" => true "ES2" => true "LATM" => true ] "gratuito" => true "lecturas" => array:2 [ "total" => 1995 "formatos" => array:3 [ "EPUB" => 45 "HTML" => 1628 "PDF" => 322 ] ] "itemSiguiente" => array:19 [ "pii" => "S0370410615001898" "issn" => "03704106" "doi" => "10.1016/j.rchipe.2015.07.019" "estado" => "S300" "fechaPublicacion" => "2015-11-01" "aid" => "81" "copyright" => "Sociedad Chilena de Pediatría" "documento" => "article" "crossmark" => 1 "licencia" => "http://creativecommons.org/licenses/by-nc-nd/4.0/" "subdocumento" => "fla" "cita" => "Rev Chil Ped. 2015;86:410-4" "abierto" => array:3 [ "ES" => true "ES2" => true "LATM" => true ] "gratuito" => true "lecturas" => array:2 [ "total" => 1264 "formatos" => array:3 [ "EPUB" => 53 "HTML" => 859 "PDF" => 352 ] ] "es" => array:13 [ "idiomaDefecto" => true "cabecera" => "<span class="elsevierStyleTextfn">Artículo original</span>" "titulo" => "Vasodilatación mediada por flujo en niños con sobrepeso" "tienePdf" => "es" "tieneTextoCompleto" => "es" "tieneResumen" => array:2 [ 0 => "es" 1 => "en" ] "paginas" => array:1 [ 0 => array:2 [ "paginaInicial" => "410" "paginaFinal" => "414" ] ] "titulosAlternativos" => array:1 [ "en" => array:1 [ "titulo" => "Flow mediated vasodilation in overweight children" ] ] "contieneResumen" => array:2 [ "es" => true "en" => true ] "contieneTextoCompleto" => array:1 [ "es" => true ] "contienePdf" => array:1 [ "es" => true ] "resumenGrafico" => array:2 [ "original" => 0 "multimedia" => array:7 [ "identificador" => "fig0015" "etiqueta" => "Figura 3" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr3.jpeg" "Alto" => 1121 "Ancho" => 790 "Tamanyo" => 45910 ] ] "descripcion" => array:1 [ "es" => "<p id="spar0055" class="elsevierStyleSimplePara elsevierViewall">Relación de la vasodilatación mediada por flujo (VMF) con hipertensión arterial.</p>" ] ] ] "autores" => array:1 [ 0 => array:2 [ "autoresLista" => "Diego Rodríguez, Mauricio Coll, Rafael Guerrero, Liliana Henao" "autores" => array:4 [ 0 => array:2 [ "nombre" => "Diego" "apellidos" => "Rodríguez" ] 1 => array:2 [ "nombre" => "Mauricio" "apellidos" => "Coll" ] 2 => array:2 [ "nombre" => "Rafael" "apellidos" => "Guerrero" ] 3 => array:2 [ "nombre" => "Liliana" "apellidos" => "Henao" ] ] ] ] ] "idiomaDefecto" => "es" "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/S0370410615001898?idApp=UINPBA00004N" "url" => "/03704106/0000008600000006/v1_201512120022/S0370410615001898/v1_201512120022/es/main.assets" ] "itemAnterior" => array:19 [ "pii" => "S0370410615001825" "issn" => "03704106" "doi" => "10.1016/j.rchipe.2015.06.021" "estado" => "S300" "fechaPublicacion" => "2015-11-01" "aid" => "74" "copyright" => "Sociedad Chilena de Pediatría" "documento" => "article" "crossmark" => 1 "licencia" => "http://creativecommons.org/licenses/by-nc-nd/4.0/" "subdocumento" => "fla" "cita" => "Rev Chil Ped. 2015;86:399-403" "abierto" => array:3 [ "ES" => true "ES2" => true "LATM" => true ] "gratuito" => true "lecturas" => array:2 [ "total" => 1424 "formatos" => array:3 [ "EPUB" => 46 "HTML" => 925 "PDF" => 453 ] ] "es" => array:13 [ "idiomaDefecto" => true "cabecera" => "<span class="elsevierStyleTextfn">Artículo original</span>" "titulo" => "¿Qué información preoperatoria desean los padres de niños que serán operados?" "tienePdf" => "es" "tieneTextoCompleto" => "es" "tieneResumen" => array:2 [ 0 => "es" 1 => "en" ] "paginas" => array:1 [ 0 => array:2 [ "paginaInicial" => "399" "paginaFinal" => "403" ] ] "titulosAlternativos" => array:1 [ "en" => array:1 [ "titulo" => "What preoperative information do the parents of children undergoing surgery want?" ] ] "contieneResumen" => array:2 [ "es" => true "en" => true ] "contieneTextoCompleto" => array:1 [ "es" => true ] "contienePdf" => array:1 [ "es" => true ] "resumenGrafico" => array:2 [ "original" => 0 "multimedia" => array:7 [ "identificador" => "fig0005" "etiqueta" => "Figura 1" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr1.jpeg" "Alto" => 1355 "Ancho" => 1645 "Tamanyo" => 129730 ] ] "descripcion" => array:1 [ "es" => "<p id="spar0055" class="elsevierStyleSimplePara elsevierViewall">Contenidos de la información preoperatoria recibida y deseada.</p>" ] ] ] "autores" => array:1 [ 0 => array:2 [ "autoresLista" => "Josefina Sartori, Pilar Espinoza, María Soledad Díaz, Constanza Ferdinand, Héctor J. Lacassie, Alejandro González" "autores" => array:6 [ 0 => array:2 [ "nombre" => "Josefina" "apellidos" => "Sartori" ] 1 => array:2 [ "nombre" => "Pilar" "apellidos" => "Espinoza" ] 2 => array:2 [ "nombre" => "María Soledad" "apellidos" => "Díaz" ] 3 => array:2 [ "nombre" => "Constanza" "apellidos" => "Ferdinand" ] 4 => array:2 [ "nombre" => "Héctor J." "apellidos" => "Lacassie" ] 5 => array:2 [ "nombre" => "Alejandro" "apellidos" => "González" ] ] ] ] ] "idiomaDefecto" => "es" "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/S0370410615001825?idApp=UINPBA00004N" "url" => "/03704106/0000008600000006/v1_201512120022/S0370410615001825/v1_201512120022/es/main.assets" ] "en" => array:19 [ "idiomaDefecto" => true "cabecera" => "<span class="elsevierStyleTextfn">Original article</span>" "titulo" => "Decreased lung compliance increases preload dynamic tests in a pediatric acute lung injury model" "tieneTextoCompleto" => true "paginas" => array:1 [ 0 => array:2 [ "paginaInicial" => "404" "paginaFinal" => "409" ] ] "autores" => array:1 [ 0 => array:4 [ "autoresLista" => "Benjamín Erranz, Franco Díaz, Alejandro Donoso, Tatiana Salomón, Cristóbal Carvajal, María Fernanda Torres, Pablo Cruces" "autores" => array:7 [ 0 => array:3 [ "nombre" => "Benjamín" "apellidos" => "Erranz" "referencia" => array:1 [ 0 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">a</span>" "identificador" => "aff0005" ] ] ] 1 => array:3 [ "nombre" => "Franco" "apellidos" => "Díaz" "referencia" => array:1 [ 0 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">b</span>" "identificador" => "aff0010" ] ] ] 2 => array:3 [ "nombre" => "Alejandro" "apellidos" => "Donoso" "referencia" => array:1 [ 0 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">c</span>" "identificador" => "aff0015" ] ] ] 3 => array:3 [ "nombre" => "Tatiana" "apellidos" => "Salomón" "referencia" => array:1 [ 0 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">d</span>" "identificador" => "aff0020" ] ] ] 4 => array:3 [ "nombre" => "Cristóbal" "apellidos" => "Carvajal" "referencia" => array:1 [ 0 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">d</span>" "identificador" => "aff0020" ] ] ] 5 => array:3 [ "nombre" => "María Fernanda" "apellidos" => "Torres" "referencia" => array:1 [ 0 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">d</span>" "identificador" => "aff0020" ] ] ] 6 => array:4 [ "nombre" => "Pablo" "apellidos" => "Cruces" "email" => array:1 [ 0 => "pcrucesr@gmail.com" ] "referencia" => array:3 [ 0 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">e</span>" "identificador" => "aff0025" ] 1 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">f</span>" "identificador" => "aff0030" ] 2 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">*</span>" "identificador" => "cor0005" ] ] ] ] "afiliaciones" => array:6 [ 0 => array:3 [ "entidad" => "Centro de Medicina Regenerativa, Facultad de Medicina, Clínica Alemana Universidad del Desarrollo, Santiago, Chile" "etiqueta" => "a" "identificador" => "aff0005" ] 1 => array:3 [ "entidad" => "Department of Paediatric, Division of Pediatric Critical Care, University of Alabama at Birmingham, USA" "etiqueta" => "b" "identificador" => "aff0010" ] 2 => array:3 [ "entidad" => "Unidad de Paciente Crítico Pediátrico, Hospital Clínico Metropolitano La Florida, Santiago, Chile" "etiqueta" => "c" "identificador" => "aff0015" ] 3 => array:3 [ "entidad" => "Unidad de Cuidados Intensivos Pediátrica, Clínica Alemana de Santiago, Chile" "etiqueta" => "d" "identificador" => "aff0020" ] 4 => array:3 [ "entidad" => "Unidad de Paciente Crítico Pediátrico, Hospital El Carmen de Maipú, Santiago, Chile" "etiqueta" => "e" "identificador" => "aff0025" ] 5 => array:3 [ "entidad" => "Centro de Investigación de Medicina Veterinaria, Escuela de Medicina Veterinaria, Facultad de Ecología y Recursos Naturales, Universidad Andrés Bello, Santiago, Chile" "etiqueta" => "f" "identificador" => "aff0030" ] ] "correspondencia" => array:1 [ 0 => array:3 [ "identificador" => "cor0005" "etiqueta" => "⁎" "correspondencia" => "Corresponding author." ] ] ] ] "titulosAlternativos" => array:1 [ "es" => array:1 [ "titulo" => "Una compliance pulmonar disminuida incrementa los test dinámicos de precarga en un modelo pediátrico de lesión pulmonar aguda" ] ] "resumenGrafico" => array:2 [ "original" => 0 "multimedia" => array:7 [ "identificador" => "fig0020" "etiqueta" => "Figure 4" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr4.jpeg" "Alto" => 2388 "Ancho" => 1553 "Tamanyo" => 214755 ] ] "descripcion" => array:1 [ "en" => "<p id="spar0060" class="elsevierStyleSimplePara elsevierViewall">Changes in stroke volume variation (SVV) and pulse pressure variation (PPV) in each animal mechanically ventilated with a tidal volume (<span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span>) of 6 and 12<span class="elsevierStyleHsp" style=""></span>mL/kg after acute lung injury induction.</p>" ] ] ] "textoCompleto" => "<span class="elsevierStyleSections"><span id="sec0005" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0065">Introduction</span><p id="par0005" class="elsevierStylePara elsevierViewall">Intravenous fluid administration is a common therapy in critically ill patients, serving as the cornerstone of initial treatment in many conditions. Recent data suggest that fluid management has a major impact on the severity and outcome of critical illness.<a class="elsevierStyleCrossRef" href="#bib0140"><span class="elsevierStyleSup">1</span></a> Knowing that excessive administration of fluids and development of fluid overload are associated with negative effects, the main question when deciding fluid administration is whether there will be beneficial effect on hemodynamics, specifically on cardiac output (CO). Preload dynamic tests, pulse pressure variation (PPV) and stroke volume variation (SVV) have emerged as powerful tools to predict response to fluid administration in different clinical settings.<a class="elsevierStyleCrossRefs" href="#bib0145"><span class="elsevierStyleSup">2–5</span></a> Many clinical and experimental studies have determined that PPV >10% and SVV >13% are associated with a significant increase in CO after fluid administration, thus predicting fluid responsiveness. These tests are based on the Frank–Starling Law, which describes the relationship between preload (end-diastolic volume or pressure) and stroke volume. As shown in <a class="elsevierStyleCrossRef" href="#fig0005">Fig. 1</a> two zones can be identified: a steep portion of the curve where changes in preload produce significant changes in CO, and a flat portion of the curve where changes in preload do not significantly change CO (dark gray). Periodic changes in ventricular filling pressures (i.e. preload) occur due to cyclical positive pressure administered during mechanical ventilation. Cyclic changes in stroke volume are greater when the ventricles operate on the steep rather than flat portion of the Frank–Starling curve. Preload dynamic test can identify this particular situation and predict response to fluid administration.<a class="elsevierStyleCrossRef" href="#bib0165"><span class="elsevierStyleSup">6</span></a> Of note, due to complex cardiopulmonary interactions, preload dynamic indices do not depend only on cardiac preload.<a class="elsevierStyleCrossRefs" href="#bib0170"><span class="elsevierStyleSup">7,8</span></a> Experimental and small clinical studies have demonstrated that pulmonary and other cardiovascular factors may play a role in the PPV and SVV measurements, though exact mechanisms are not well understood.<a class="elsevierStyleCrossRefs" href="#bib0180"><span class="elsevierStyleSup">9–12</span></a></p><elsevierMultimedia ident="fig0005"></elsevierMultimedia><p id="par0010" class="elsevierStylePara elsevierViewall">Acute lung injury (ALI) is a frequent cause of hypoxemia, loss of respiratory system compliance (<span class="elsevierStyleItalic">C</span><span class="elsevierStyleInf">RS</span>) and pulmonary edema. Caution has been claimed respect to the usefulness of dynamic preload tests in patients with ALI where due to low <span class="elsevierStyleItalic">C</span><span class="elsevierStyleInf">RS</span> the transmission of positive pressure to the vascular compartment of the lungs, great thoracic veins and the heart may be decreased.<a class="elsevierStyleCrossRef" href="#bib0185"><span class="elsevierStyleSup">10</span></a> On the other hand, subjects with ALI have a decreased compliance resulting in higher changes in tracheal pressure for a given tidal volume (<span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span>).<a class="elsevierStyleCrossRef" href="#bib0190"><span class="elsevierStyleSup">11</span></a> In addition, the standard of care of ALI patients include MV with low <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span>. This ventilatory strategy may theoretically decrease the pressure transmitted from the airways to the pleural and pericardial spaces, diminishing the variations of SV and PP.<a class="elsevierStyleCrossRefs" href="#bib0195"><span class="elsevierStyleSup">12,13</span></a> Accordingly, the effect of a decreased <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span> on preload dynamic tests in ALI is unpredictable.<a class="elsevierStyleCrossRef" href="#bib0205"><span class="elsevierStyleSup">14</span></a> Because there are marked differences in respiratory and cardiovascular physiology in children with respect to adults (e.g. chest wall compliance, airway wall compliance and resistance, heart rate, stroke volume, pulmonary and systemic vascular resistance, aortic elastance and compliance, metabolic rate), basis for many age-specific differences in the cardiovascular and metabolic responses to injury, these observations should be carefully examined.<a class="elsevierStyleCrossRefs" href="#bib0210"><span class="elsevierStyleSup">15–19</span></a></p><p id="par0015" class="elsevierStylePara elsevierViewall">In summary, preload dynamic tests may be an inaccurate measure of filling in cases where <span class="elsevierStyleItalic">C</span><span class="elsevierStyleInf">RS</span> or <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span> are low, even more so considering the particular features pediatric physiology. The aim of this work was to determine the effect of delivered <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span> size on PPV and SVV in normal and reduced lung compliance conditions in a pediatric ALI model.</p></span><span id="sec0010" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0070">Material and method</span><p id="par0020" class="elsevierStylePara elsevierViewall">The experimental protocol was approved by Facultad de Medicina Clínica Alemana Universidad del Desarrollo Ethics Committee and the CONICYT (Comisión Nacional de Investigación Científica y Tecnológica) Bioethics Advisory Committee. All of the experimental procedures were consistent with the Guiding Principles in the Care and Use of Laboratory Animals adopted by the American Physiological Society.</p><span id="sec0015" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0075">Subjects</span><p id="par0025" class="elsevierStylePara elsevierViewall">Twenty anesthetized and mechanically ventilated piglets (5.2<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>0.4<span class="elsevierStyleHsp" style=""></span>kg).</p></span><span id="sec0020" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0080">Surgical preparation</span><p id="par0030" class="elsevierStylePara elsevierViewall">The trachea was cannulated with a 3.5<span class="elsevierStyleHsp" style=""></span>mm tracheostomy tube, the left jugular vein with a 4F catheter and the right axillary artery with a 4F thermistor-tipped catheter (PiCCO<span class="elsevierStyleSup">®</span> PV2014L08, Pulsion Medical Systems, Munich, Germany), all via cut down. Anesthesia and neuromuscular blockade were maintained by continuous infusion of propofol (10<span class="elsevierStyleHsp" style=""></span>mg/kg/h), fentanyl (4<span class="elsevierStyleHsp" style=""></span>mcg/kg/h) and pancuronium (0.2<span class="elsevierStyleHsp" style=""></span>mg/kg/h) during the experiment. Piglets were ventilated in a volume-controlled mode (EVITA XL<span class="elsevierStyleSup">®</span>/Capnoplus, Dräger Medical, Lübeck, Germany) with a positive end-expiratory pressure of 5<span class="elsevierStyleHsp" style=""></span>cmH<span class="elsevierStyleInf">2</span>O, a <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span> of 9<span class="elsevierStyleHsp" style=""></span>mL/kg, inspiratory time of 0.75<span class="elsevierStyleHsp" style=""></span>s and a FiO<span class="elsevierStyleInf">2</span> of 0.5. The respiratory rate was adjusted to maintain the end-tidal carbon dioxide concentration (ET-CO<span class="elsevierStyleInf">2</span>) at 45<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>5<span class="elsevierStyleHsp" style=""></span>mmHg. Normal saline at 5<span class="elsevierStyleHsp" style=""></span>mL/kg/h was administered during instrumentation. Heart rate, oxygen saturation, central temperature, mean arterial pressure (MAP) and central venous pressure (CVP) were monitored with an Infinity Delta XL<span class="elsevierStyleSup">®</span> monitor (Dräger Medical, Lübeck, Germany). Zero pressure was set at the midaxillary line. Temperature was kept at 37.0<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>0.6<span class="elsevierStyleHsp" style=""></span>°C.</p></span><span id="sec0025" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0085">Acute lung injury</span><p id="par0035" class="elsevierStylePara elsevierViewall">After surgical preparation, each animal was placed in lateral decubitus and a 10% (v/v) solution of polysorbate 20 (Tween<span class="elsevierStyleSup">®</span> 20 [polyoxyethylene 20 sorbitan monolaurate], Sigma-Aldrich, MO, USA) in saline (1<span class="elsevierStyleHsp" style=""></span>mL/kg) was instilled in the airway of the dependent lung via a 2-mm catheter. The procedure was repeated with the animal rotated to the opposite side. Residual fluid was suctioned from the airway. Lung injury was targeted to achieve a partial pressure of oxygen (PaO<span class="elsevierStyleInf">2</span>)<span class="elsevierStyleHsp" style=""></span><<span class="elsevierStyleHsp" style=""></span>200<span class="elsevierStyleHsp" style=""></span>Torr with FiO<span class="elsevierStyleInf">2</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>1 in the supine position at 20<span class="elsevierStyleHsp" style=""></span>min after polysorbate 20 instillation. If this target was not met, polysorbate 20 instillation was repeated:<ul class="elsevierStyleList" id="lis0005"><li class="elsevierStyleListItem" id="lsti0005"><span class="elsevierStyleLabel">(i)</span><p id="par0040" class="elsevierStylePara elsevierViewall"><span class="elsevierStyleItalic">Pulmonary measurements</span>: Arterial blood gases were determined with an i-STAT<span class="elsevierStyleSup">®</span> System and i-STAT<span class="elsevierStyleSup">®</span> Cartridges EG6+ (Abbott Laboratories, Princeton, NJ) from blood samples drawn from the arterial catheter. Oxygenation was assessed by the PaO<span class="elsevierStyleInf">2</span>/FiO<span class="elsevierStyleInf">2</span> ratio. Static <span class="elsevierStyleItalic">C</span><span class="elsevierStyleInf">RS</span> was calculated as <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span>/(<span class="elsevierStyleItalic">P</span><span class="elsevierStyleInf">pl</span><span class="elsevierStyleHsp" style=""></span>−<span class="elsevierStyleHsp" style=""></span>PEEP<span class="elsevierStyleInf">TOT</span>), where <span class="elsevierStyleItalic">P</span><span class="elsevierStyleInf">pl</span> is plateau pressure measured after a 4-s inspiratory hold and PEEP<span class="elsevierStyleInf">TOT</span> is total PEEP measured after a 4-s expiratory hold. These variables were recorded from the ventilator display.</p></li><li class="elsevierStyleListItem" id="lsti0010"><span class="elsevierStyleLabel">(ii)</span><p id="par0045" class="elsevierStylePara elsevierViewall"><span class="elsevierStyleItalic">Hemodynamic measurements</span>: cardiac output (CO) was calculated by transpulmonary thermodilution and continuous CO was obtained with PiCCO system calibrated at baseline and after ALI induction according to manufacturer's instructions. According to studies in humans at rest and under different types of environmental stress, a functional definition of ‘normovolemia’ would be by its ability to provide the heart with an optimal central blood volume, i.e. that cardiac pumping capacity is not limited by its preload. Functional normovolemia is the point in the cardiac preload/output relationship at which CO does not increase further under circumstances where venous return is unimpeded.<a class="elsevierStyleCrossRef" href="#bib0235"><span class="elsevierStyleSup">20</span></a> Normovolemic state was standardized prior registering hemodynamic data at baseline and after ALI induction, with successive 10<span class="elsevierStyleHsp" style=""></span>mL/kg intravenous 6% hydroxy-ethyl starch (HES) boluses until CO did not increase by more than 10%. HES was administered over 10<span class="elsevierStyleHsp" style=""></span>min and personnel deciding fluid administration were blinded for preload dynamic indices.</p></li><li class="elsevierStyleListItem" id="lsti0015"><span class="elsevierStyleLabel">(iii)</span><p id="par0050" class="elsevierStylePara elsevierViewall"><span class="elsevierStyleItalic">Preload dynamic indices</span>: PPV and SVV were obtained from the PiCCO<span class="elsevierStyleSup">®</span> monitor display. According to PiCCO algorithm SVV is calculated from the mean values of four maximum (SV<span class="elsevierStyleInf">max</span>) and minimum (SV<span class="elsevierStyleInf">min</span>) stroke volumes averaged during the previous 30<span class="elsevierStyleHsp" style=""></span>s (SV<span class="elsevierStyleInf">mean</span>): SVV<span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>(SV<span class="elsevierStyleInf">max</span><span class="elsevierStyleHsp" style=""></span>−<span class="elsevierStyleHsp" style=""></span>SV<span class="elsevierStyleInf">min</span>)/SV<span class="elsevierStyleInf">mean</span>. PPV is calculated during the same time interval: PPV<span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>(PP<span class="elsevierStyleInf">max</span><span class="elsevierStyleHsp" style=""></span>−<span class="elsevierStyleHsp" style=""></span>PP<span class="elsevierStyleInf">min</span>)/PP<span class="elsevierStyleInf">mean</span> (2.7). PPV and SVV were registered at baseline and 1<span class="elsevierStyleHsp" style=""></span>h after ALI induction, with low <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span> (6<span class="elsevierStyleHsp" style=""></span>mL/kg) and high <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span> (12<span class="elsevierStyleHsp" style=""></span>mL/kg). PiCCO<span class="elsevierStyleSup">®</span> system was calibrated with transpulmonary thermodilution (TPTD) at baseline and after polysorbate 20 instillation and PPV and SVV were registered after 5<span class="elsevierStyleHsp" style=""></span>min of stability (<a class="elsevierStyleCrossRef" href="#fig0010">Fig. 2</a>).</p><elsevierMultimedia ident="fig0010"></elsevierMultimedia></li></ul></p><p id="par0055" class="elsevierStylePara elsevierViewall">At the end of the study period, while under anesthesia, the animals were euthanized by 10% potassium chloride infusion until the detection of ventricular fibrillation or asystole.</p></span><span id="sec0030" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0090">Statistical analysis</span><p id="par0060" class="elsevierStylePara elsevierViewall">Data are expressed in mean<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>SEM. Analysis of variance for repeated measurements was used for comparison between the preload dynamic indicators with high and low <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span>. Significance was set at <span class="elsevierStyleItalic">P</span><span class="elsevierStyleHsp" style=""></span><<span class="elsevierStyleHsp" style=""></span>0.05.</p></span></span><span id="sec0035" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0095">Results</span><p id="par0065" class="elsevierStylePara elsevierViewall">All subjects completed the experimental protocol. After polysorbate 20 instillation, a significant decrease in PaO<span class="elsevierStyleInf">2</span>/FiO<span class="elsevierStyleInf">2</span> from 345<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>14 to 155<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>8<span class="elsevierStyleHsp" style=""></span>Torr and <span class="elsevierStyleItalic">C</span><span class="elsevierStyleInf">RS</span> from 1.58<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>0.13 to 0.93<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>0.05<span class="elsevierStyleHsp" style=""></span>mL/cmH<span class="elsevierStyleInf">2</span>O/kg was observed (both <span class="elsevierStyleItalic">P</span><span class="elsevierStyleHsp" style=""></span><<span class="elsevierStyleHsp" style=""></span>0.01). Also there was an increase in HR (133<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>7–162<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>8<span class="elsevierStyleHsp" style=""></span>bpm, <span class="elsevierStyleItalic">P</span><span class="elsevierStyleHsp" style=""></span><<span class="elsevierStyleHsp" style=""></span>0.001) without changes in MAP (74<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>3–76<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>3<span class="elsevierStyleHsp" style=""></span>mmHg), CVP (7.6<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>0.4–7.6<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>0.6<span class="elsevierStyleHsp" style=""></span>mmHg) and CO (4.1<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>0.2–4.3<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>0.3<span class="elsevierStyleHsp" style=""></span>L/min/m<span class="elsevierStyleSup">2</span>).</p></span><span id="sec0040" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0100">Preload dynamic indices</span><p id="par0070" class="elsevierStylePara elsevierViewall">Subjects required 14<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>2<span class="elsevierStyleHsp" style=""></span>mL/kg at baseline and 25<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>3<span class="elsevierStyleHsp" style=""></span>mL/kg after ALI induction for volemic status optimization. All subjects maintained sinus rhythm during experiment.</p><p id="par0075" class="elsevierStylePara elsevierViewall">At baseline PPV was 8.9<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>1.2 and 10.7<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>1.1% with low and high <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span> (<span class="elsevierStyleItalic">P</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>0.058) and SVV was 8.7<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>1.2 and 9.7<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>1.1% (<span class="elsevierStyleItalic">P</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>0.45), respectively. After ALI induction PPV increased from 8.9<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>1.2 to 12.4<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>1.1% (<span class="elsevierStyleItalic">P</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>0.037) and SVV from 8.5<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>1.0 to 12.7<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>1.2% (<span class="elsevierStyleItalic">P</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>0.03) with low and high <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span> respectively (<a class="elsevierStyleCrossRefs" href="#fig0015">Figs. 3 and 4</a>).</p><elsevierMultimedia ident="fig0015"></elsevierMultimedia><elsevierMultimedia ident="fig0020"></elsevierMultimedia></span><span id="sec0045" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0105">Discussion</span><p id="par0080" class="elsevierStylePara elsevierViewall">The main finding of this experimental study is that high <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span> significantly increased PPV and SVV when <span class="elsevierStyleItalic">C</span><span class="elsevierStyleInf">RS</span> was reduced, but not when <span class="elsevierStyleItalic">C</span><span class="elsevierStyleInf">RS</span> was normal in subjects with optimized intravascular volume (not hypovolemic).</p><p id="par0085" class="elsevierStylePara elsevierViewall">Preload dynamic indices are produced by the transmission of airway pressure to the pleural and pericardial spaces, determining cyclic changes in venous return, cardiac preload and afterload. Therefore, its clinical use could be theoretically limited in conditions where the airway pressure transmitted to the intrathoracic spaces is low (i.e. low VT and low CRS). Recent studies in anesthetized large animals and critically ill adults reported that <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span> size influences preload dynamic indices.<a class="elsevierStyleCrossRefs" href="#bib0240"><span class="elsevierStyleSup">21,22</span></a> Our results differ with previous studies where size of delivered <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span> has been an indication as the major determinant of preload dynamic indices.<a class="elsevierStyleCrossRefs" href="#bib0185"><span class="elsevierStyleSup">10,23</span></a> In this model of normovolemic subjects, when <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span> was applied in a lung with a reduced <span class="elsevierStyleItalic">C</span><span class="elsevierStyleInf">RS</span> the effect was more pronounced, resulting in a leftward shift on the Frank–Starling curve and consequently a greater variation of stroke volume and pulse pressure.<a class="elsevierStyleCrossRef" href="#bib0255"><span class="elsevierStyleSup">24</span></a> We found that the reduction of <span class="elsevierStyleItalic">C</span><span class="elsevierStyleInf">RS</span> was a factor that amplified the effect of <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span> on preload dynamic tests. In a small series of ARDS patients, Vieillard Baron13 concluded that VT and not the airway pressure itself, was the determinant for the afterload and the RV stroke work, both components of the PPV. However, an interesting prior study in a model of oleic acid-lung injury reported that the influence of lung edema in the transmission of airway pressure to the pleural space depends significantly on the peak volume during the inspiration.<a class="elsevierStyleCrossRef" href="#bib0260"><span class="elsevierStyleSup">25</span></a> While most studies used oleic acid-lung injury, where the main pathogenic mechanism is an increase in pulmonary vascular permeability, we used a surfactant deactivation model. It has been documented that tracheal instillation of polysorbate 20 produce high-tension pulmonary edema. Despite these differences, the lung edema in subjects with injured lungs was similar to other models of lung injury.<a class="elsevierStyleCrossRefs" href="#bib0185"><span class="elsevierStyleSup">10,12,16,26</span></a> Thus, in models of pulmonary edema, transmission of airway pressure to pleural space and vascular structures may be relevant, and influence preload dynamic markers. Accordingly Huang et al. published a clinical series of patients with severe ARDS ventilated with a low <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span> strategy, finding that PPV maintained a good prediction for volume response. Although the <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span> reported was approximately 6<span class="elsevierStyleHsp" style=""></span>mL/kg, the mean peak inspiratory pressure was nearly 34 cmH<span class="elsevierStyleInf">2</span>O, obtaining an at least 20<span class="elsevierStyleHsp" style=""></span>cmH<span class="elsevierStyleInf">2</span>O driving pressure.<a class="elsevierStyleCrossRef" href="#bib0270"><span class="elsevierStyleSup">27</span></a> These findings agree with our results, since the cyclical changes for the arterial pressure and the volume ejection would be secondary to the generated airway pressure and not to the <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span> absolute value.</p><p id="par0090" class="elsevierStylePara elsevierViewall">Additionally we used a model of increased preload (normovolemia as defined, and corroborated by maintaining cardiac output and volume preload after ALI) so that the ventricle is operating on the flat portion of the Frank–Starling curve, not only is the likelihood of finding a change in PPV and SVV with increased <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span> reduced, but based on the literature and even in a pediatric model one would not expect the PPV and SVV to change under the condition of <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span> of 6<span class="elsevierStyleHsp" style=""></span>mL/kg. The finding of no increase in PPV and SVV with <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span> 12<span class="elsevierStyleHsp" style=""></span>mL/kg differs from that previously reported<a class="elsevierStyleCrossRefs" href="#bib0185"><span class="elsevierStyleSup">10,17</span></a> and could at least partially be explained by the normovolaemic model used. It would appear that a <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span> of 12<span class="elsevierStyleHsp" style=""></span>mL/kg more closely resembles that of 10<span class="elsevierStyleHsp" style=""></span>mL/kg rather than 15<span class="elsevierStyleHsp" style=""></span>mL/kg if this study is compared with that by Renner et al.<a class="elsevierStyleCrossRef" href="#bib0220"><span class="elsevierStyleSup">17</span></a></p><p id="par0095" class="elsevierStylePara elsevierViewall">This study has some limitations. The measurement of pleural pressure would allow us to determine the chest wall compliance and specifically address its effects on preload dynamic markers, but it was not performed due to technical reasons. Additionally, tachycardia and decreased SV after ALI are also known factors that influence preload dynamic markers.</p><p id="par0100" class="elsevierStylePara elsevierViewall">In conclusion, preload dynamic indexes are powerful tools when deciding fluid administration in critically ill subjects, but other factors, such as <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span> and <span class="elsevierStyleItalic">C</span><span class="elsevierStyleInf">RS</span>, must be considered for correct interpretation. Future clinical studies should address these variables in addition to hemodynamic parameters and preload dynamic markers for fluid management strategies in critically ill children.</p></span><span id="sec0050" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0110">Funding</span><p id="par0105" class="elsevierStylePara elsevierViewall">This work was supported by grant Fondecyt <span class="elsevierStyleGrantNumber" refid="gs1">11075041</span> from <span class="elsevierStyleGrantSponsor" id="gs1">CONICYT</span> (Comisión Nacional de Investigación Científica y Tecnológica, Chile) to Pablo Cruces.</p></span><span id="sec0055" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0115">Conflicts of interest</span><p id="par0110" class="elsevierStylePara elsevierViewall">This article meets all requirements about informed consent/acknowledgement, ethics committee, funding, animal research and lack conflict of interest, as appropriate.</p></span></span>" "textoCompletoSecciones" => array:1 [ "secciones" => array:12 [ 0 => array:3 [ "identificador" => "xres588028" "titulo" => "Abstract" "secciones" => array:4 [ 0 => array:2 [ "identificador" => "abst0005" "titulo" => "Background" ] 1 => array:2 [ "identificador" => "abst0010" "titulo" => "Material and method" ] 2 => array:2 [ "identificador" => "abst0015" "titulo" => "Results" ] 3 => array:2 [ "identificador" => "abst0020" "titulo" => "Conclusions" ] ] ] 1 => array:2 [ "identificador" => "xpalclavsec603814" "titulo" => "Keywords" ] 2 => array:3 [ "identificador" => "xres588029" "titulo" => "Resumen" "secciones" => array:4 [ 0 => array:2 [ "identificador" => "abst0025" "titulo" => "Introducción" ] 1 => array:2 [ "identificador" => "abst0030" "titulo" => "Material y método" ] 2 => array:2 [ "identificador" => "abst0035" "titulo" => "Resultados" ] 3 => array:2 [ "identificador" => "abst0040" "titulo" => "Conclusiones" ] ] ] 3 => array:2 [ "identificador" => "xpalclavsec603813" "titulo" => "Palabras clave" ] 4 => array:2 [ "identificador" => "sec0005" "titulo" => "Introduction" ] 5 => array:3 [ "identificador" => "sec0010" "titulo" => "Material and method" "secciones" => array:4 [ 0 => array:2 [ "identificador" => "sec0015" "titulo" => "Subjects" ] 1 => array:2 [ "identificador" => "sec0020" "titulo" => "Surgical preparation" ] 2 => array:2 [ "identificador" => "sec0025" "titulo" => "Acute lung injury" ] 3 => array:2 [ "identificador" => "sec0030" "titulo" => "Statistical analysis" ] ] ] 6 => array:2 [ "identificador" => "sec0035" "titulo" => "Results" ] 7 => array:2 [ "identificador" => "sec0040" "titulo" => "Preload dynamic indices" ] 8 => array:2 [ "identificador" => "sec0045" "titulo" => "Discussion" ] 9 => array:2 [ "identificador" => "sec0050" "titulo" => "Funding" ] 10 => array:2 [ "identificador" => "sec0055" "titulo" => "Conflicts of interest" ] 11 => array:1 [ "titulo" => "References" ] ] ] "pdfFichero" => "main.pdf" "tienePdf" => true "fechaRecibido" => "2015-02-25" "fechaAceptado" => "2015-06-09" "PalabrasClave" => array:2 [ "en" => array:1 [ 0 => array:4 [ "clase" => "keyword" "titulo" => "Keywords" "identificador" => "xpalclavsec603814" "palabras" => array:5 [ 0 => "Hemodynamics" 1 => "Preload" 2 => "Acute lung injury" 3 => "Mechanical ventilation" 4 => "Pediatric" ] ] ] "es" => array:1 [ 0 => array:4 [ "clase" => "keyword" "titulo" => "Palabras clave" "identificador" => "xpalclavsec603813" "palabras" => array:5 [ 0 => "Hemodinamia" 1 => "Precarga" 2 => "Lesión Pulmonar Aguda" 3 => "Ventilación Mecánica" 4 => "Pediatría" ] ] ] ] "tieneResumen" => true "resumen" => array:2 [ "en" => array:3 [ "titulo" => "Abstract" "resumen" => "<span id="abst0005" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0010">Background</span><p id="spar0005" class="elsevierStyleSimplePara elsevierViewall">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 (<span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span>) on PPV and SVV in the context of normal and reduced lung compliance in a piglet model.</p></span> <span id="abst0010" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0015">Material and method</span><p id="spar0010" class="elsevierStyleSimplePara elsevierViewall">Twenty large-white piglets (5.2<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>0.4<span class="elsevierStyleHsp" style=""></span>kg) were anesthetized, paralyzed and monitored with pulse contour analysis. PPV and SVV were recorded during mechanical ventilation with a <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span> of 6 and 12<span class="elsevierStyleHsp" style=""></span>mL/kg (low and high <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span>, respectively), both before and after tracheal instillation of polysorbate 20.</p></span> <span id="abst0015" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0020">Results</span><p id="spar0015" class="elsevierStyleSimplePara elsevierViewall">Before acute lung injury (ALI) induction, modifications of <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span> did not significantly change PPV and SVV readings. After ALI, PPV and SVV were significantly greater during ventilation with a high <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span> compared to a low <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span> (PPV increased from 8.9<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>1.2 to 12.4<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>1.1%, and SVV from 8.5<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>1.0 to 12.7<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>1.2%, both <span class="elsevierStyleItalic">P</span><span class="elsevierStyleHsp" style=""></span><<span class="elsevierStyleHsp" style=""></span>0.01).</p></span> <span id="abst0020" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0025">Conclusions</span><p id="spar0020" class="elsevierStyleSimplePara elsevierViewall">This study found that a high <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span> 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.</p></span>" "secciones" => array:4 [ 0 => array:2 [ "identificador" => "abst0005" "titulo" => "Background" ] 1 => array:2 [ "identificador" => "abst0010" "titulo" => "Material and method" ] 2 => array:2 [ "identificador" => "abst0015" "titulo" => "Results" ] 3 => array:2 [ "identificador" => "abst0020" "titulo" => "Conclusions" ] ] ] "es" => array:3 [ "titulo" => "Resumen" "resumen" => "<span id="abst0025" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0035">Introducción</span><p id="spar0025" class="elsevierStyleSimplePara elsevierViewall">Test dinámicos de precarga, variación de presión de pulso (PPV) y variación de volumen sistólico (SVV) han emergido como herramientas poderosas para predecir respuesta a la administración de fluidos. Actualmente la influencia de factores distintos a la precarga en la determinación de los test dinámicos de precarga es pobremente conocida en pediatría. Nuestro objetivo fue medir el efecto del volumen tidal (V<span class="elsevierStyleInf">T</span>) sobre PPV y SVV en un contexto de compliance pulmonar normal y disminuida en un modelo porcino.</p></span> <span id="abst0030" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0040">Material y método</span><p id="spar0030" class="elsevierStyleSimplePara elsevierViewall">Veinte cerditos Large-White anestesiados y paralizados (5,2<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>0,4<span class="elsevierStyleHsp" style=""></span>kg). PPV y SVV fueron medidos por análisis de contorno de pulso durante ventilación con V<span class="elsevierStyleInf">T</span> de 6 y 12<span class="elsevierStyleHsp" style=""></span>mL/kg (V<span class="elsevierStyleInf">T</span> bajo y alto, respectivamente), ambos previo y posterior a lesión pulmonar aguda (ALI) químicamente inducida con instilación traqueal de polisorbato 20.</p></span> <span id="abst0035" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0045">Resultados</span><p id="spar0035" class="elsevierStyleSimplePara elsevierViewall">Previo a inducción de ALI, PPV y SVV no tuvieron cambios significativos al modificar el V<span class="elsevierStyleInf">T</span>. Sin embargo, después de ALI, PPV y SVV fueron significativamente mayores durante ventilación con V<span class="elsevierStyleInf">T</span> alto, respecto a V<span class="elsevierStyleInf">T</span> bajo (PPV aumentó de 8,9<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>1,2 a 12,4<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>1,1%, y SVV de 8,5<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>1,0 a 12,7<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>1,2%, ambos <span class="elsevierStyleItalic">P</span><span class="elsevierStyleHsp" style=""></span><<span class="elsevierStyleHsp" style=""></span>0,01).</p></span> <span id="abst0040" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0050">Conclusiones</span><p id="spar0040" class="elsevierStyleSimplePara elsevierViewall">Este estudio encontró que un V<span class="elsevierStyleInf">T</span> alto y una compliance pulmonar disminuida debido a ALI incrementan los test dinámicos de precarga, con una mayor influencia de esta última. En sujetos con ALI la compliance pulmonar debiera ser considerada al interpretar los test dinámicos de precarga.</p></span>" "secciones" => array:4 [ 0 => array:2 [ "identificador" => "abst0025" "titulo" => "Introducción" ] 1 => array:2 [ "identificador" => "abst0030" "titulo" => "Material y método" ] 2 => array:2 [ "identificador" => "abst0035" "titulo" => "Resultados" ] 3 => array:2 [ "identificador" => "abst0040" "titulo" => "Conclusiones" ] ] ] ] "multimedia" => array:4 [ 0 => array:7 [ "identificador" => "fig0005" "etiqueta" => "Figure 1" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr1.jpeg" "Alto" => 1126 "Ancho" => 2510 "Tamanyo" => 124068 ] ] "descripcion" => array:1 [ "en" => "<p id="spar0045" class="elsevierStyleSimplePara elsevierViewall">Frank–Starling relationship. Once the ventricle is operating near the steep part, volume expansion induces a significant increase in cardiac output. The pulse pressure (PPV) and stroke volume (SVV) variations are marked. By contrast, once the ventricle is functioning on the flat part of the curve, fluid infusion has poor effect on the cardiac output. BP, blood pressure; Paw, airway pressure; PP, pulse pressure.</p>" ] ] 1 => array:7 [ "identificador" => "fig0010" "etiqueta" => "Figure 2" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr2.jpeg" "Alto" => 1275 "Ancho" => 2489 "Tamanyo" => 125713 ] ] "descripcion" => array:1 [ "en" => "<p id="spar0050" class="elsevierStyleSimplePara elsevierViewall">Experimental protocol.</p>" ] ] 2 => array:7 [ "identificador" => "fig0015" "etiqueta" => "Figure 3" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr3.jpeg" "Alto" => 2308 "Ancho" => 1593 "Tamanyo" => 109522 ] ] "descripcion" => array:1 [ "en" => "<p id="spar0055" class="elsevierStyleSimplePara elsevierViewall">Stroke volume variation (SVV) and pulse pressure variation (PPV) in euvolemic piglets mechanically ventilated with a tidal volume (<span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span>) 6 and 12<span class="elsevierStyleHsp" style=""></span>mL/kg at baseline (A) and after ALI induction (B).</p>" ] ] 3 => array:7 [ "identificador" => "fig0020" "etiqueta" => "Figure 4" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr4.jpeg" "Alto" => 2388 "Ancho" => 1553 "Tamanyo" => 214755 ] ] "descripcion" => array:1 [ "en" => "<p id="spar0060" class="elsevierStyleSimplePara elsevierViewall">Changes in stroke volume variation (SVV) and pulse pressure variation (PPV) in each animal mechanically ventilated with a tidal volume (<span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span>) of 6 and 12<span class="elsevierStyleHsp" style=""></span>mL/kg after acute lung injury induction.</p>" ] ] ] "bibliografia" => array:2 [ "titulo" => "References" "seccion" => array:1 [ 0 => array:2 [ "identificador" => "bibs0005" "bibliografiaReferencia" => array:27 [ 0 => array:3 [ "identificador" => "bib0140" "etiqueta" => "1" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Fluid management in acute kidney injury" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:1 [ 0 => "S.L. Goldstein" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.1177/0885066612465816" "Revista" => array:6 [ "tituloSerie" => "J Intensive Care Med" "fecha" => "2014" "volumen" => "29" "paginaInicial" => "183" "paginaFinal" => "189" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/23753221" "web" => "Medline" ] ] ] ] ] ] ] ] 1 => array:3 [ "identificador" => "bib0145" "etiqueta" => "2" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Dynamic changes in arterial waveform derived variables and fluid responsiveness in mechanically ventilated patients: a systematic review of the literature" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:4 [ 0 => "P.E. Marik" 1 => "R. Cavallazzi" 2 => "T. Vasu" 3 => "A. Hirani" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.1097/CCM.0b013e3181a590da" "Revista" => array:6 [ "tituloSerie" => "Crit Care Med" "fecha" => "2009" "volumen" => "37" "paginaInicial" => "2642" "paginaFinal" => "2647" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/19602972" "web" => "Medline" ] ] ] ] ] ] ] ] 2 => array:3 [ "identificador" => "bib0150" "etiqueta" => "3" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Stroke volume variation as a predictor of fluid responsiveness in patients undergoing brain surgery" "autores" => array:1 [ 0 => array:2 [ "etal" => true "autores" => array:3 [ 0 => "H. Berkenstadt" 1 => "N. Margalit" 2 => "M. Hadani" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:6 [ "tituloSerie" => "Anesth Analg" "fecha" => "2001" "volumen" => "92" "paginaInicial" => "984" "paginaFinal" => "989" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/11273937" "web" => "Medline" ] ] ] ] ] ] ] ] 3 => array:3 [ "identificador" => "bib0155" "etiqueta" => "4" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Online monitoring of pulse pressure variation to guide fluid therapy after cardiac surgery" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:6 [ 0 => "J.O. Auler" 1 => "F. Galas" 2 => "L. Hajjar" 3 => "L. Santos" 4 => "T. Carvalho" 5 => "F. Michard" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.1213/01.ane.0000287664.03547.c6" "Revista" => array:6 [ "tituloSerie" => "Anesth Analg" "fecha" => "2008" "volumen" => "106" "paginaInicial" => "1201" "paginaFinal" => "1206" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/18349193" "web" => "Medline" ] ] ] ] ] ] ] ] 4 => array:3 [ "identificador" => "bib0160" "etiqueta" => "5" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "The ability of stroke volume variations obtained with Vigileo/FloTrac system to monitor fluid responsiveness in mechanically ventilated patients" "autores" => array:1 [ 0 => array:2 [ "etal" => true "autores" => array:3 [ 0 => "M. Cannesson" 1 => "H. Musard" 2 => "O. Desebbe" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.1213/ane.0b013e318192a36b" "Revista" => array:6 [ "tituloSerie" => "Anesth Analg" "fecha" => "2009" "volumen" => "108" "paginaInicial" => "513" "paginaFinal" => "517" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/19151280" "web" => "Medline" ] ] ] ] ] ] ] ] 5 => array:3 [ "identificador" => "bib0165" "etiqueta" => "6" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "A comparison of changes in cardiac preload variables during graded hypovolemia and hypervolemia in mechanically ventilated dogs" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:5 [ 0 => "Y. Fujita" 1 => "T. Yamamoto" 2 => "I. Sano" 3 => "N. Yoshioka" 4 => "H. Hinenoya" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.1213/01.ANE.0000136776.35317.EC" "Revista" => array:6 [ "tituloSerie" => "Anesth Analg" "fecha" => "2004" "volumen" => "99" "paginaInicial" => "1780" "paginaFinal" => "1786" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/15562071" "web" => "Medline" ] ] ] ] ] ] ] ] 6 => array:3 [ "identificador" => "bib0170" "etiqueta" => "7" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Stroke volume variation as an indicator of fluid responsiveness using pulse contour analysis in mechanically ventilated patients" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:4 [ 0 => "C. Wiesenack" 1 => "C. Prasser" 2 => "G. Rödig" 3 => "C. Keyl" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:6 [ "tituloSerie" => "Anesth Analg" "fecha" => "2003" "volumen" => "96" "paginaInicial" => "1254" "paginaFinal" => "1257" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/12707116" "web" => "Medline" ] ] ] ] ] ] ] ] 7 => array:3 [ "identificador" => "bib0175" "etiqueta" => "8" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Should dynamic parameters for prediction of fluid responsiveness be indexed to the tidal volume?" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:3 [ 0 => "S.T. Vistisen" 1 => "J. Koefoed-Nielsen" 2 => "A. Larsson" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.1111/j.1399-6576.2009.02114.x" "Revista" => array:6 [ "tituloSerie" => "Acta Anaesthesiol Scand" "fecha" => "2010" "volumen" => "54" "paginaInicial" => "191" "paginaFinal" => "198" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/19764908" "web" => "Medline" ] ] ] ] ] ] ] ] 8 => array:3 [ "identificador" => "bib0180" "etiqueta" => "9" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Stroke volume of the heart and thoracic fluid content during head-up and head-down tilt in humans" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:5 [ 0 => "J.J. Van Lieshout" 1 => "M.P. Harms" 2 => "F. Pott" 3 => "M. Jenstrup" 4 => "N.H. Secher" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.1111/j.1399-6576.2005.00841.x" "Revista" => array:6 [ "tituloSerie" => "Acta Anaesthesiol Scand" "fecha" => "2005" "volumen" => "49" "paginaInicial" => "1287" "paginaFinal" => "1292" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/16146465" "web" => "Medline" ] ] ] ] ] ] ] ] 9 => array:3 [ "identificador" => "bib0185" "etiqueta" => "10" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Heart-lung interactions with different ventilatory settings during acute lung injury and hypovolaemia: an experimental study" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:5 [ 0 => "F.J. da Silva Ramos" 1 => "E.M. de Oliveira" 2 => "M. Park" 3 => "G.P.P. Schettino" 4 => "L.C.P. Azevedo" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.1093/bja/aeq404" "Revista" => array:6 [ "tituloSerie" => "Br J Anaesth" "fecha" => "2011" "volumen" => "106" "paginaInicial" => "394" "paginaFinal" => "402" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/21278154" "web" => "Medline" ] ] ] ] ] ] ] ] 10 => array:3 [ "identificador" => "bib0190" "etiqueta" => "11" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Pulse pressure variation: does lung compliance really matter" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:2 [ 0 => "X. Monnet" 1 => "J.L. Teboul" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.1097/CCM.0b013e318246b717" "Revista" => array:6 [ "tituloSerie" => "Crit Care Med" "fecha" => "2012" "volumen" => "40" "paginaInicial" => "1691" "paginaFinal" => "1692" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/22511168" "web" => "Medline" ] ] ] ] ] ] ] ] 11 => array:3 [ "identificador" => "bib0195" "etiqueta" => "12" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Changes in arterial pressure during mechanical ventilation" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:1 [ 0 => "F. Michard" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:6 [ "tituloSerie" => "Anesthesiology" "fecha" => "2005" "volumen" => "103" "paginaInicial" => "419" "paginaFinal" => "428" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/16052125" "web" => "Medline" ] ] ] ] ] ] ] ] 12 => array:3 [ "identificador" => "bib0200" "etiqueta" => "13" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Cyclic changes in right ventricular output impedance during mechanical ventilation" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:6 [ 0 => "A. Vieillard-Baron" 1 => "Y. Loubieres" 2 => "J.M. Schmitt" 3 => "B. Page" 4 => "O. Dubourg" 5 => "F. Jardin" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:6 [ "tituloSerie" => "J Appl Physiol" "fecha" => "1999" "volumen" => "87" "paginaInicial" => "1644" "paginaFinal" => "1650" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/10562603" "web" => "Medline" ] ] ] ] ] ] ] ] 13 => array:3 [ "identificador" => "bib0205" "etiqueta" => "14" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Why do pulse pressure variations fail to predict the response to fluids in acute respiratory distress syndrome patients ventilated with low tidal volume?" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:2 [ 0 => "D. De Backer" 1 => "S. Scolletta" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.1186/cc10111" "Revista" => array:5 [ "tituloSerie" => "Crit Care" "fecha" => "2011" "volumen" => "15" "paginaInicial" => "150" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/21489328" "web" => "Medline" ] ] ] ] ] ] ] ] 14 => array:3 [ "identificador" => "bib0210" "etiqueta" => "15" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Global end-diastolic volume during different loading conditions in a pediatric animal model" "autores" => array:1 [ 0 => array:2 [ "etal" => true "autores" => array:3 [ 0 => "J. Renner" 1 => "P. Meybohm" 2 => "M. Gruenewald" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.1213/01.ane.0000281152.72734.d0" "Revista" => array:6 [ "tituloSerie" => "Anesth Analg" "fecha" => "2007" "volumen" => "105" "paginaInicial" => "1243" "paginaFinal" => "1249" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/17959950" "web" => "Medline" ] ] ] ] ] ] ] ] 15 => array:3 [ "identificador" => "bib0215" "etiqueta" => "16" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Estimation of the parameters of cardiac function and of blood volume by arterial thermodilution in an infant animal model" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:5 [ 0 => "J. Lopez-Herce" 1 => "M. Ruperez" 2 => "C. Sanchez" 3 => "C. Garcia" 4 => "E. Garcia" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.1111/j.1460-9592.2005.01831.x" "Revista" => array:6 [ "tituloSerie" => "Paediatr Anaesth" "fecha" => "2006" "volumen" => "16" "paginaInicial" => "635" "paginaFinal" => "640" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/16719879" "web" => "Medline" ] ] ] ] ] ] ] ] 16 => array:3 [ "identificador" => "bib0220" "etiqueta" => "17" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Pulse pressure variation and stroke volume variation during different loading conditions in a paediatric animal model" "autores" => array:1 [ 0 => array:2 [ "etal" => true "autores" => array:3 [ 0 => "J. Renner" 1 => "E. Cavus" 2 => "P. Meybohm" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.1111/j.1399-6576.2007.01544.x" "Revista" => array:6 [ "tituloSerie" => "Acta Anaesthesiol Scand" "fecha" => "2008" "volumen" => "52" "paginaInicial" => "374" "paginaFinal" => "380" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/18205899" "web" => "Medline" ] ] ] ] ] ] ] ] 17 => array:3 [ "identificador" => "bib0225" "etiqueta" => "18" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Differences in airway wall compliance as a possible mechanism for wheezing disorders in infants" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:3 [ 0 => "U. Frey" 1 => "A.C. Jackson" 2 => "M. Silverman" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:6 [ "tituloSerie" => "Eur Respir J" "fecha" => "1998" "volumen" => "12" "paginaInicial" => "136" "paginaFinal" => "142" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/9701428" "web" => "Medline" ] ] ] ] ] ] ] ] 18 => array:3 [ "identificador" => "bib0230" "etiqueta" => "19" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Lung and chest wall mechanics in anesthetized children Influence of body position" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:4 [ 0 => "J. Ingimarsson" 1 => "A. Thorsteinsson" 2 => "A. Larsson" 3 => "O. Werner" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.1164/ajrccm.162.2.9905051" "Revista" => array:6 [ "tituloSerie" => "Am J Respir Crit Care Med" "fecha" => "2000" "volumen" => "162" "paginaInicial" => "412" "paginaFinal" => "417" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/10934062" "web" => "Medline" ] ] ] ] ] ] ] ] 19 => array:3 [ "identificador" => "bib0235" "etiqueta" => "20" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Central cardiovascular variables at a maximal mixed venous oxygen saturation in severe hepatic failure" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:5 [ 0 => "E. Ejlersen" 1 => "C. Skak" 2 => "K. Moller" 3 => "F. Pott" 4 => "N.H. Secher" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:6 [ "tituloSerie" => "Transplant Proc" "fecha" => "1995" "volumen" => "27" "paginaInicial" => "3506" "paginaFinal" => "3507" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/8540072" "web" => "Medline" ] ] ] ] ] ] ] ] 20 => array:3 [ "identificador" => "bib0240" "etiqueta" => "21" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Influence of tidal volume on left ventricular stroke volume variation measured by pulse contour analysis in mechanically ventilated patients" "autores" => array:1 [ 0 => array:2 [ "etal" => true "autores" => array:3 [ 0 => "D.A. Reuter" 1 => "J. Bayerlein" 2 => "M.S. Goepfert" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.1007/s00134-003-1649-7" "Revista" => array:6 [ "tituloSerie" => "Intensive Care Med" "fecha" => "2003" "volumen" => "29" "paginaInicial" => "476" "paginaFinal" => "480" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/12579420" "web" => "Medline" ] ] ] ] ] ] ] ] 21 => array:3 [ "identificador" => "bib0245" "etiqueta" => "22" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "The influence of tidal volume on the dynamic variables of fluid responsiveness in critically ill patients" "autores" => array:1 [ 0 => array:2 [ "etal" => true "autores" => array:3 [ 0 => "C. Charron" 1 => "C. Fessenmeyer" 2 => "C. Cosson" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.1213/01.ane.0000209015.21418.f4" "Revista" => array:6 [ "tituloSerie" => "Anesth Analg" "fecha" => "2006" "volumen" => "102" "paginaInicial" => "1511" "paginaFinal" => "1517" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/16632835" "web" => "Medline" ] ] ] ] ] ] ] ] 22 => array:3 [ "identificador" => "bib0250" "etiqueta" => "23" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Influence of lung and chest wall compliances on transmission of airway pressure to the pleural space in critically ill patients" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:4 [ 0 => "J. Jardin" 1 => "B. Genevray" 2 => "D. Brun-Ney" 3 => "J.P. Bourdarias" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:6 [ "tituloSerie" => "Chest" "fecha" => "1985" "volumen" => "88" "paginaInicial" => "653" "paginaFinal" => "658" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/3902386" "web" => "Medline" ] ] ] ] ] ] ] ] 23 => array:3 [ "identificador" => "bib0255" "etiqueta" => "24" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "The physiological basis of arterial pressure variation during positive-pressure ventilation" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:1 [ 0 => "A. Perel" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:5 [ "tituloSerie" => "Réanimation" "fecha" => "2005" "volumen" => "14" "paginaInicial" => "162" "paginaFinal" => "171" ] ] ] ] ] ] 24 => array:3 [ "identificador" => "bib0260" "etiqueta" => "25" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Transmission of airway pressure to pleural space during lung edema and chest wall restriction" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:4 [ 0 => "R.J. O’Quin" 1 => "J.J. Marini" 2 => "B.H. Culver" 3 => "J. Butler" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:6 [ "tituloSerie" => "J Appl Physiol" "fecha" => "1985" "volumen" => "59" "paginaInicial" => "1171" "paginaFinal" => "1177" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/3902775" "web" => "Medline" ] ] ] ] ] ] ] ] 25 => array:3 [ "identificador" => "bib0265" "etiqueta" => "26" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Surfactant deactivation in a paediatric model induces hypovolemia and fluid shift to the extravascular lung compartment" "autores" => array:1 [ 0 => array:2 [ "etal" => true "autores" => array:3 [ 0 => "F. Díaz" 1 => "B. Erranz" 2 => "A. Donoso" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.1111/pan.12037" "Revista" => array:6 [ "tituloSerie" => "Paediatr Anaesth" "fecha" => "2013" "volumen" => "23" "paginaInicial" => "250" "paginaFinal" => "257" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/23043489" "web" => "Medline" ] ] ] ] ] ] ] ] 26 => array:3 [ "identificador" => "bib0270" "etiqueta" => "27" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Prediction of fluid responsiveness in acute respiratory distress syndrome patients ventilated with low tidal volume and high positive end-expiratory pressure" "autores" => array:1 [ 0 => array:2 [ "etal" => true "autores" => array:3 [ 0 => "C.C. Huang" 1 => "J.Y. Fu" 2 => "H.C. Hu" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.1097/CCM.0b013e318186b74e" "Revista" => array:6 [ "tituloSerie" => "Crit Care Med" "fecha" => "2008" "volumen" => "36" "paginaInicial" => "2810" "paginaFinal" => "2816" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/18766099" "web" => "Medline" ] ] ] ] ] ] ] ] ] ] ] ] ] "idiomaDefecto" => "en" "url" => "/03704106/0000008600000006/v1_201512120022/S0370410615001850/v1_201512120022/en/main.assets" "Apartado" => array:4 [ "identificador" => "42943" "tipo" => "SECCION" "en" => array:2 [ "titulo" => "Artículos originales" "idiomaDefecto" => true ] "idiomaDefecto" => "en" ] "PDF" => "https://static.elsevier.es/multimedia/03704106/0000008600000006/v1_201512120022/S0370410615001850/v1_201512120022/en/main.pdf?idApp=UINPBA00004N&text.app=https://www.elsevier.es/" "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/S0370410615001850?idApp=UINPBA00004N" ]
| Year/Month | Html | Total | |
|---|---|---|---|
| 2024 November | 4 | 0 | 4 |
| 2024 October | 33 | 4 | 37 |
| 2024 September | 72 | 3 | 75 |
| 2024 August | 45 | 7 | 52 |
| 2024 July | 46 | 3 | 49 |
| 2024 June | 34 | 2 | 36 |
| 2024 May | 33 | 5 | 38 |
| 2024 April | 30 | 10 | 40 |
| 2024 March | 42 | 4 | 46 |
| 2024 February | 44 | 7 | 51 |
| 2024 January | 43 | 6 | 49 |
| 2023 December | 35 | 10 | 45 |
| 2023 November | 46 | 5 | 51 |
| 2023 October | 46 | 12 | 58 |
| 2023 September | 45 | 4 | 49 |
| 2023 August | 24 | 5 | 29 |
| 2023 July | 20 | 8 | 28 |
| 2023 June | 23 | 3 | 26 |
| 2023 May | 46 | 9 | 55 |
| 2023 April | 45 | 4 | 49 |
| 2023 March | 39 | 1 | 40 |
| 2023 February | 41 | 0 | 41 |
| 2023 January | 26 | 7 | 33 |
| 2022 December | 39 | 5 | 44 |
| 2022 November | 41 | 7 | 48 |
| 2022 October | 27 | 10 | 37 |
| 2022 September | 36 | 11 | 47 |
| 2022 August | 52 | 10 | 62 |
| 2022 July | 52 | 14 | 66 |
| 2022 June | 54 | 10 | 64 |
| 2022 May | 53 | 6 | 59 |
| 2022 April | 82 | 22 | 104 |
| 2022 March | 118 | 8 | 126 |
| 2022 February | 121 | 8 | 129 |
| 2022 January | 88 | 15 | 103 |
| 2021 December | 83 | 15 | 98 |
| 2021 November | 80 | 10 | 90 |
| 2021 October | 105 | 13 | 118 |
| 2021 September | 58 | 12 | 70 |
| 2021 August | 96 | 9 | 105 |
| 2021 July | 54 | 9 | 63 |
| 2021 June | 48 | 7 | 55 |
| 2021 May | 62 | 6 | 68 |
| 2021 April | 151 | 17 | 168 |
| 2021 March | 68 | 6 | 74 |
| 2021 February | 38 | 14 | 52 |
| 2021 January | 33 | 15 | 48 |
| 2020 December | 39 | 11 | 50 |
| 2020 November | 32 | 10 | 42 |
| 2020 October | 28 | 8 | 36 |
| 2020 September | 31 | 10 | 41 |
| 2020 August | 47 | 11 | 58 |
| 2020 July | 31 | 17 | 48 |
| 2020 June | 32 | 20 | 52 |
| 2020 May | 33 | 6 | 39 |
| 2020 April | 23 | 5 | 28 |
| 2020 March | 39 | 5 | 44 |
| 2020 February | 34 | 5 | 39 |
| 2020 January | 41 | 6 | 47 |
| 2019 December | 35 | 7 | 42 |
| 2019 November | 32 | 3 | 35 |
| 2019 October | 28 | 2 | 30 |
| 2019 September | 38 | 5 | 43 |
| 2019 August | 28 | 1 | 29 |
| 2019 July | 42 | 9 | 51 |
| 2019 June | 90 | 9 | 99 |
| 2019 May | 138 | 5 | 143 |
| 2019 April | 72 | 11 | 83 |
| 2019 March | 18 | 0 | 18 |
| 2019 February | 20 | 5 | 25 |
| 2019 January | 23 | 3 | 26 |
| 2018 December | 22 | 2 | 24 |
| 2018 November | 42 | 2 | 44 |
| 2018 October | 31 | 15 | 46 |
| 2018 September | 27 | 4 | 31 |
| 2018 August | 31 | 2 | 33 |
| 2018 July | 16 | 0 | 16 |
| 2018 June | 19 | 3 | 22 |
| 2018 May | 32 | 2 | 34 |
| 2018 April | 85 | 1 | 86 |
| 2018 March | 21 | 2 | 23 |
| 2018 February | 11 | 1 | 12 |
| 2018 January | 21 | 1 | 22 |
| 2017 December | 9 | 0 | 9 |
| 2017 November | 19 | 1 | 20 |
| 2017 October | 7 | 3 | 10 |
| 2017 September | 9 | 5 | 14 |
| 2017 August | 10 | 7 | 17 |
| 2017 July | 23 | 3 | 26 |
| 2017 June | 38 | 11 | 49 |
| 2017 May | 25 | 2 | 27 |
| 2017 April | 15 | 9 | 24 |
| 2017 March | 10 | 22 | 32 |
| 2017 February | 14 | 0 | 14 |
| 2017 January | 13 | 1 | 14 |
| 2016 December | 25 | 5 | 30 |
| 2016 November | 25 | 2 | 27 |
| 2016 October | 52 | 2 | 54 |
| 2016 September | 43 | 5 | 48 |
| 2016 August | 47 | 3 | 50 |
| 2016 July | 40 | 1 | 41 |
| 2016 June | 30 | 15 | 45 |
| 2016 May | 27 | 16 | 43 |
| 2016 April | 26 | 16 | 42 |
| 2016 March | 51 | 14 | 65 |
| 2016 February | 27 | 31 | 58 |
| 2016 January | 30 | 24 | 54 |
| 2015 December | 27 | 18 | 45 |
Show all
