Examinando por Autor "Cruces, Pablo"
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Ítem A machine-learning regional clustering approach to understand ventilator-induced lung injury: a proof-of-concept experimental study(Springer Nature, 2024-12) Cruces, Pablo; Retamal, Jaime; Damián, Andrés; Lago, Graciela; Blasina, Fernanda; Oviedo, Vanessa; Medina, Tania; Pérez, Agustín; Vaamonde, Lucía; Dapueto, Rosina; González-Dambrauskas, Sebastian; Serra, AlbertoBackground: The spatiotemporal progression and patterns of tissue deformation in ventilator-induced lung injury (VILI) remain understudied. Our aim was to identify lung clusters based on their regional mechanical behavior over space and time in lungs subjected to VILI using machine-learning techniques. Results: Ten anesthetized pigs (27 ± 2 kg) were studied. Eight subjects were analyzed. End-inspiratory and end-expiratory lung computed tomography scans were performed at the beginning and after 12 h of one-hit VILI model. Regional image-based biomechanical analysis was used to determine end-expiratory aeration, tidal recruitment, and volumetric strain for both early and late stages. Clustering analysis was performed using principal component analysis and K-Means algorithms. We identified three different clusters of lung tissue: Stable, Recruitable Unstable, and Non-Recruitable Unstable. End-expiratory aeration, tidal recruitment, and volumetric strain were significantly different between clusters at early stage. At late stage, we found a step loss of end-expiratory aeration among clusters, lowest in Stable, followed by Unstable Recruitable, and highest in the Unstable Non-Recruitable cluster. Volumetric strain remaining unchanged in the Stable cluster, with slight increases in the Recruitable cluster, and strong reduction in the Unstable Non-Recruitable cluster. Conclusions: VILI is a regional and dynamic phenomenon. Using unbiased machine-learning techniques we can identify the coexistence of three functional lung tissue compartments with different spatiotemporal regional biomechanical behavior. © The Author(s) 2024.Ítem A physiological approach to understand the role of respiratory effort in the progression of lung injury in SARS-CoV-2 infection(BioMed Central Ltd, 2020-08) Cruces, Pablo; Retamal, Jaime; Hurtado, Daniel E.; Erranz, Benjamín; Iturrieta, Pablo; González, Carlos; Díaz, FrancoDeterioration of lung function during the first week of COVID-19 has been observed when patients remain with insufficient respiratory support. Patient self-inflicted lung injury (P-SILI) is theorized as the responsible, but there is not robust experimental and clinical data to support it. Given the limited understanding of P-SILI, we describe the physiological basis of P-SILI and we show experimental data to comprehend the role of regional strain and heterogeneity in lung injury due to increased work of breathing. In addition, we discuss the current approach to respiratory support for COVID-19 under this point of view. © 2020 The Author(s).Ítem Acute flaccid myelitis and enterovirus infection: a severe emerging disease(Sociedad Chilena de Pediatria, 2022-07) Bustos B., Raúl; Díaz, Franco; Cores, Camila; Castro Z., Francisca; Cruces, PabloAcute flaccid myelitis (AFM) is a neuroinflammatory disease characterized by acute asymmetric weakness of the limbs associated with lesions of the gray matter of the spinal cord. It mainly affects children and has been increasingly identified since 2014. Objective: To describe a severe emerging neurological disease in Chile. Clinical Case: Three children (2 females), previously healthy were included. The age at the onset was between 4 and 6 years. All presented an acute febrile illness associated with upper respiratory symptoms, rapid onset of proximal asymmetric limb weakness, spinal fluid pleocytosis, and enterovirus isolated from nasopharyngeal swab; two patients developed tetraparesis. The MRI of the spinal cord showed T2 hyperintensity of the grey matter. The three patients were admitted to the Pediatric Intensive Care Unit (PICU), and two required mechanical ventilation. No significant improvements were observed after the use of immunomodulatory therapy and plasma exchange. At 12 months of follow-up, one case was quadriplegic and ventilator-dependent; the second died of ventricular arrhythmia in the PICU, and the third one is under rehabilitation with partial recovery. Conclusions: We report the first cases of this severe emerging neurological disease in our country. In a child with predominantly proximal and asymmetric acute limb paralysis, pediatricians must have a high index of suspicion for AFM. Since it can progress rapidly and lead to respiratory failure, suspected AFM should be considered a medical emergency. © 2022, Sociedad Chilena de Pediatria. All rights reserved.Ítem Comparison of Interleukin-6 Plasma Concentration in Multisystem Inflammatory Syndrome in Children Associated With SARS-CoV-2 and Pediatric Sepsis(Frontiers Media S.A., 2021-11) Diaz, Franco; Bustos B., Raúl; Yagnam, Felipe; Karsies, Todd J.; Vásquez-Hoyos, Pablo; Jaramillo-Bustamante, Juan-Camilo; Gonzalez-Dambrauskas, Sebastián; Drago, Michelle; Cruces, PabloImportance: Multisystem Inflammatory Syndrome in Children (MIS-C) associated with SARS-CoV-2 infection is thought to be driven by a post-viral dysregulated immune response, where interleukin 6 (IL-6) might have a central role. In this setting, IL-6 inhibitors are prescribed as immunomodulation in cases refractory to standard therapy. Objective: To compare plasma IL-6 concentration between critically ill children with MIS-C and sepsis. Design: A retrospective cohort study from previously collected data. Setting: Individual patient data were gathered from three different international datasets. Participants: Critically ill children between 1 month-old and 18 years old, with an IL-6 level measured within 48 h of admission to intensive care. Septic patients were diagnosed according to Surviving Sepsis Campaign definition and MIS-C cases by CDC criteria. We excluded children with immunodeficiency or immunosuppressive therapy. Exposure: None. Main Outcome(s) and Measure(s): The primary outcome was IL-6 plasma concentration in MIS-C and sepsis group at admission to the intensive care unit. We described demographics, inflammatory biomarkers, and clinical outcomes for both groups. A subgroup analysis for shock in each group was done. Results: We analyzed 66 patients with MIS-C and 44 patients with sepsis. MIS-C cases were older [96 (48, 144) vs. 20 (5, 132) months old, p < 0.01], but no differences in sex (41 vs. 43% female, p = 0.8) compared to septic group. Mechanical ventilation use was 48.5 vs. 93% (p < 0.001), vasoactive drug use 79 vs. 66% (p = 0.13), and mortality 4.6 vs. 34.1% (p < 0.01) in MIS-C group compared to sepsis. IL-6 was 156 (36, 579) ng/dl in MIS-C and 1,432 (122, 6,886) ng/dl in sepsis (p < 0.01), while no significant differences were observed in procalcitonin (PCT) and c-reactive protein (CRP). 52/66 (78.8%) patients had shock in MIS-C group, and 29/44 (65.9%) had septic shock in sepsis group. Septic shock had a significantly higher plasma IL-6 concentration than the three other sub-groups. Differences in IL-6, CRP, and PCT were not statistically different between MIS-C with and without shock. Conclusions and Relevance: IL-6 plasma concentration was elevated in critically ill MIS-C patients but at levels much lower than those of sepsis. Furthermore, IL-6 levels don't discriminate between MIS-C cases with and without shock. These results lead us to question the role of IL-6 in the pathobiology of MIS-C, its diagnosis, clinical outcomes, and, more importantly, the off-label use of IL-6 inhibitors for these cases. Copyright © 2021 Diaz, Bustos B, Yagnam, Karsies, Vásquez-Hoyos, Jaramillo-Bustamante, Gonzalez-Dambrauskas, Drago and Cruces.Ítem Decreased lung compliance increases preload dynamic tests in a pediatric acute lung injury model(Sociedad Chilena de Pediatría, Santiago, 2015) Erranz, Benjamín; Díaz, Franco; Donoso, Alejandro; Salomón, Tatiana; Carvajal, Cristóbal; Torres, María Fernanda; Cruces, PabloBackground 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 ± 0.4 kg) were anesthetized, paralyzed and monitored with pulse contour analysis. PPV and SVV were recorded during mechanical ventilation with a VT of 6 and 12 mL/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.Ítem Executive Summary of the Second International Guidelines for the Diagnosis and Management of Pediatric Acute Respiratory Distress Syndrome (PALICC-2)(Lippincott Williams and Wilkins, 2023-02) Emeriaud, Guillaume; López-Fernández, Yolanda M.; Iyer, Narayan Prabhu; Bembea, Melania M.; Agulnik, Asya; Barbaro, Ryan P.; Baudin, Florent; Bhalla, Anoopindar; Brunow De Carvalho, Werther; Carroll, Christopher L.; Cheifetz, Ira M.; Chisti, Mohammod J.; Cruces, Pablo; Curley, Martha A. Q.; Dahmer, Mary K.; Dalton, Heidi J.; Erickson, Simon J.; Essouri, Sandrine; Fernández, Analía; Flori, Heidi R.; Grunwell, Jocelyn R.; Jouvet, Philippe; Killien, Elizabeth Y.; Kneyber, Martin C. J.; Kudchadkar, Sapna R.; Korang, Steven Kwasi; Lee, Jan Hau; Macrae, Duncan J.; Maddux, Aline; Modesto I Alapont, Vicent; Morrow, Brenda M.; Nadkarni, Vinay M.; Napolitano, Natalie; Newth, Christopher J. L.; Pons-Odena, Martí; Quasney, Michael W.; Rajapreyar, Prakadeshwari; Rambaud, Jerome; Randolph, Adrienne G.; Rimensberger, Peter; Rowan, Courtney M.; Sanchez-Pinto, L. Nelson; Sapru, Anil; Sauthier, Michael; Shein, Steve L.; Smith, Lincoln S.; Steffen, Katerine; Takeuchi, Muneyuki; Thomas, Neal J.; Tse, Sze Man; Valentine, Stacey; Ward, Shan; Watson, R. Scott; Yehya, Nadir; Zimmerman, Jerry J.; Khemani, Robinder G.OBJECTIVES: We sought to update our 2015 work in the Second Pediatric Acute Lung Injury Consensus Conference (PALICC-2) guidelines for the diagnosis and management of pediatric acute respiratory distress syndrome (PARDS), considering new evidence and topic areas that were not previously addressed. DESIGN: International consensus conference series involving 52 multidisciplinary international content experts in PARDS and four methodology experts from 15 countries, using consensus conference methodology, and implementation science. SETTING: Not applicable. PATIENTS: Patients with or at risk for PARDS. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Eleven subgroups conducted systematic or scoping reviews addressing 11 topic areas: 1) definition, incidence, and epidemiology; 2) pathobiology, severity, and risk stratification; 3) ventilatory support; 4) pulmonary-specific ancillary treatment; 5) nonpulmonary treatment; 6) monitoring; 7) noninvasive respiratory support; 8) extracorporeal support; 9) morbidity and long-term outcomes; 10) clinical informatics and data science; and 11) resource-limited settings. The search included MEDLINE, EMBASE, and CINAHL Complete (EBSCOhost) and was updated in March 2022. Grading of Recommendations, Assessment, Development, and Evaluation methodology was used to summarize evidence and develop the recommendations, which were discussed and voted on by all PALICC-2 experts. There were 146 recommendations and statements, including: 34 recommendations for clinical practice; 112 consensus-based statements with 18 on PARDS definition, 55 on good practice, seven on policy, and 32 on research. All recommendations and statements had agreement greater than 80%. CONCLUSIONS: PALICC-2 recommendations and consensus-based statements should facilitate the implementation and adherence to the best clinical practice in patients with PARDS. These results will also inform the development of future programs of research that are crucially needed to provide stronger evidence to guide the pediatric critical care teams managing these patients. Copyright 2023 The Author(s). Published by Wolters Kluwer Health, Inc.Ítem Extracorporeal membrane oxygenation improves survival in a novel 24-hour pig model of severe acute respiratory distress syndrome(E-CENTURY PUBLISHING CORP, 2016-06) Araos, Joaquín; Alegría, Leyla; García, Patricio; Damiani, Felipe; Tapia, Pablo; Soto, Dagoberto; Salomon, Tatiana; Rodriguez, Felipe; Amthauer, Macarena; Erranz, Benjamín; Castro, Gabriel; Carreño, Pamela; Medina, Tania; Retamal, Jaime; Cruces, Pablo; Bugedo, Guillermo; Bruhn, AlejandroExtracorporeal membrane oxygenation (ECMO) is increasingly being used to treat severe acute respiratory distress syndrome (ARDS). However, there is limited clinical evidence about how to optimize the technique. Experimental research can provide an alternative to fill the actual knowledge gap. The purpose of the present study was to develop and validate an animal model of acute lung injury (ALI) which resembled severe ARDS, and which could be successfully supported with ECMO. Eighteen pigs were randomly allocated into three groups: sham, ALI, and ALI + ECMO. ALI was induced by a double-hit consisting in repeated saline lavage followed by a 2-hour period of injurious ventilation. All animals were followed up to 24 hours while being ventilated with conventional ventilation (tidal volume 10 ml/kg). The lung injury model resulted in severe hypoxemia, increased airway pressures, pulmonary hypertension, and altered alveolar membrane barrier function, as indicated by an increased protein concentration in bronchoalveolar fluid, and increased wet/dry lung weight ratio. Histologic examination revealed severe diffuse alveolar damage, characteristic of ARDS. Veno-venous ECMO was started at the end of lung injury induction with a flow > 60 ml/kg/min resulting in rapid reversal of hypoxemia and pulmonary hypertension. Mortality was 0, 66.6 and 16.6% in the SHAM, ALI and ALI + ECMO groups, respectively (p < 0.05). This is a novel clinically relevant animal model that can be used to optimize the approach to ECMO and foster translational research in extracorporeal lung support.Ítem Influence of tidal volume on pulse pressure variation and stroke volume variation during experimental intra-abdominal hypertension(BioMed Central Ltd., 2015-09) Díaz, F.; Erranz, B.; Donoso, A.; Salomon, T.; Cruces, PabloBackground: Pulse pressure variation (PPV) and stroke volume variation (SVV) are frequently used to assess fluid responsiveness in critically ill patients on mechanical ventilation (MV). There are many factors, in addition to preload that influence the magnitude of these cyclic variations. We sought to investigate the effect of tidal volume (VT) on PPV and SVV, and prediction of fluid responsiveness in a model of intra-abdominal hypertension (IAH). Methods: Twelve anesthetized and mechanically ventilated piglets on continuous pulse contour cardiac output monitoring. Hypovolemia was ruled out with 2 consecutive fluid boluses after instrumentation. IAH was induced by intraperitoneal instillation of colloid solution with a goal of reducing respiratory system compliance by 50 %. Subjects were classified as fluid responders if stroke volume increased >15 % after each fluid challenge. SVV and PPV were recorded with tidal volumes (VT) of 6, 12 and 18 ml/kg before IAH after IAH induction and after a fluid challenge during IAH. Results: VT influenced PPV and SVV at baseline and during IAH, being significantly larger with higher VT. These differences were attenuated after fluid administration in both conditions. After IAH induction, there was a significant increase in SVV with the three-tested VT, but the magnitude of that change was larger with high VT: with 6 ml/kg from 3 % (3, 4) to 5 % (4, 6.25) (p = 0.05), with 12 ml/kg from 5 % (4, 6) to 11 % (8.75, 17) (p = 0.02) and 18 ml/kg from 5 % (4,7.5) to 15 % (8.75, 19.5) (p = 0.02). Similarly, PPV increased with all the tested VT after IAH induction, being this increase larger with high VT: with 6 ml/kg from 3 % (2, 4.25) to 6 % (4.75, 7) (p = 0.05), with 12 ml/kg from 5 % (4, 6) to 13.5 % (10.25, 15.5) (p = 0.02) and 18 ml/kg from 7 % (5.5, 8.5) to 24 % (13.5, 30.25) (p = 0.02). One third of subjects responded to fluid administration after IAH, but neither SVV nor PPV were able to identify the fluid responders with the tested VT. Conclusion: IAH induction in non-hypovolemic subjects significantly increased SVV and PPV with the three tested VT, but the magnitude of that change was higher with larger VT. This observation reveals the dependence of functional hemodynamic markers on intrathoracic as well intra-abdominal pressures, in addition to volemic status. Also, PPV and SVV were unable to predict fluid responsiveness after IAH induction. Future studies should take into consideration these findings when exploring relationships between dynamic preload indicators and fluid responsiveness during IAH. © 2015 Díaz et al.Ítem Lung mechanics in pediatric acute respiratory distress syndrome associated to acute COVID-19 and MIS-C(Sociedad Chilena de Pediatria, 2023) Domínguez-Rojas, Jesús; Munoz, Álvaro Coronado; Luna-Delgado, Yesica; Alvarado-Gamarra, Giancarl; Flores, Gaudi Quispe; Caqui-Vilca, Patrick; Atamari-Anahui, Noé; Ramírez, Cleotilde Mireya Muñoz; Tello-Pezo, Mariela; Cruces, Pablo; Vásquez-Hoyos, Pablo; Díaz, FrancoObjective: To describe lung mechanics in Pediatric Acute Respiratory Distress Syndrome (PARDS) associated with acute COVID-19 and MIS-C with respiratory failure. Methods: A concurrent multi-center observational study was performed, analyzing clinical variables and pulmonary mechanics of PARDS associated with COVID-19 in 4 Pediatric intensive care units (PICU) in Peru. The subgroup analysis included PARDS associated with multisystem inflammatory syndrome in children (MIS-C), MIS-PARDS, and PARDS with COVID-19 primary respiratory infection, C-PARDS. In addition, receiver operating characteristic (ROC) curve analysis for mortality and lung mechanics was performed. Results: 30 patients were included. The age was 7.5 (4-11) years, 60% were male, and mortality was 23%. 47% corresponded to MIS-PARDS and 53% to C-PARDS groups. C-PARDS had positive RT-PCR in 67% and MIS-PARDS none (p < 0.001). C-PARDS group had more profound hypoxe-mia (P/F ratio < 100, 86% vs. 38%, p < 0.01) and higher driving-pressure [14(10-22) vs 10(10-12) cmH2O], and lower compliance of the respiratory system (CRS) [0.5 (0.3-0.6) vs 0.7(0.6-0.8) ml/kg/cmH2O] compared with MIS-PARDS (all p < 0.05). The ROC analysis for mortality showed that driving pressure had the best performance [AUC 0.91(95%CI0.81-1.00), with the best cut-off point of 15 cmH2O (100% sensitivity and 87% specificity). Mortality in C-PARDS was 38% and 7% in MIS-PARDS (p = 0.09). MV-free days were 12(0-23) in C-PARDS and 23(21-25) in MIS-PARDS (p = 0.02). Conclusion: Patients with C-PARDS have lung mechanics characteristics similar to classic moderate to severe PARDS. This was not observed in patients with MIS-C. As seen in other studies, a driving pressure ≥ 15 cmH2O was the best discriminator for mortality. These findings may help guide ventilatory management strategies for these two different presentations. © 2023, Sociedad Chilena de Pediatria. All rights reserved.Ítem Mapping regional strain in anesthetised healthy subjects during spontaneous ventilation(BMJ Open Respiratory Research, 2019) Cruces, Pablo; Erranz, Benjamin; Lillo, Felipe; Sarabia-Vallejos, Mauricio A.; Iturrieta, Pablo; Morales, Felipe; Blaha, Katherine; Medina, Tania; Diaz, Franco; Hurtado, Daniel E.Introduction Breathing produces a phenomenon of cyclic deformation throughout life. Biomechanically, deformation of the lung is measured as strain. Regional strain recently started to be recognised as a tool in the study of lung pathophysiology, but regional lung strain has not been studied in healthy subjects breathing spontaneously without voluntary or pharmacological control of ventilation. Our aim is to generate three-dimensional (3D) regional strain and heterogeneity maps of healthy rat lungs and describe their changes over time. Methods Micro-CT and image-based biomechanical analysis by finite element approach were carried out in six anaesthetised rats under spontaneous breathing in two different states, at the beginning of the experiment and after 3 hours of observation. 3D regional strain maps were constructed and divided into 10 isovolumetric region-of-interest (ROI) in three directions (apex to base, dorsal to ventral and costal to mediastinal), allowing to regionally analyse the volumetric strain, the strain progression and the strain heterogeneity. To describe in depth these parameters, and systematise their report, we defined regional strain heterogeneity index [1+strain SD ROI(x)]/[1+strain mean ROI(x)] and regional strain progression index [ROI(x)-mean of final strain/ROI(x)-mean of initial strain]. Results We were able to generate 3D regional strain maps of the lung in subjects without respiratory support, showing significant differences among the three analysed axes. We observed a significantly lower regional volumetric strain in the apex sector compared with the base, with no significant anatomical systematic differences in the other directions. This heterogeneity could not be identified with physiological or standard CT methods. There was no progression of the analysed regional volumetric strain when the two time-points were compared. Discussion It is possible to map the regional volumetric strain in the lung for healthy subjects during spontaneous breathing. Regional strain heterogeneity and changes over time can be measured using a CT image-based numerical analysis applying a finite element approach. These results support that healthy lung might have significant regional strain and its spatial distribution is highly heterogeneous. This protocol for CT image acquisition and analysis could be a useful tool for helping to understand the mechanobiology of the lung in many diseases.Ítem Mechanical power in pediatric acute respiratory distress syndrome: a PARDIE study(BioMed Central Ltd, 2022-12) Bhalla, Anoopindar K.; Klein, Margaret J.; Modesto I Alapont, Vicent; Emeriaud, Guillaume; Kneyber, Martin C. J.; Medina, Alberto; Cruces, Pablo; Diaz, Franco; Takeuchi, Muneyuki; Maddux, Aline B.; Mourani, Peter M.; Camilo, Cristina; White, Benjamin R.; Yehya, Nadir; Pappachan, John; Di Nardo, Matteo; Shein, Steven; Newth, Christopher; Khemani, Robinder; Poterala, Rossana; Fernandez, Analia; Vera, Antonio Ávila; Vidal, Nilda Agueda; Rosemary, Deheza; Turon, Gonzalo; Monjes, Cecilia; Serrate, Alejandro Siaba; Iolster, Thomas; Torres, Silvio; Castellani, Pablo; Giampieri, Martin; Pedraza, Claudia; Landry, Luis Martin; Althabe, Maria; Fortini, Yanina Vanesa; Erickson, Simon; Barr, Samantha; Shea, Sara; Butt, Warwick; Delzoppo, Carmel; Pintimalla, Alyssa; León, Alejandro Fabio Martínez; Rivera, Gustavo Alfredo Guzmán; Jouvet, Philippe; Dumitrascu, Mariana; French, Mary Ellen; Caro I, Daniel; Acuna, Carlos; Núnez, María José; Chen, Yang; Alarcón, Yurika Paola López; Izquierdo, Ledys María; Piñeres Olave, Byron Enrique; Hoyos, Pablo Vásquez; Bourgoin, Pierre; Baudin, Florent; Briassoulis, George; Ilia, Stavroula; Chiusolo, Fabrizio; Shime, NobuakiMechanical power is a composite variable for energy transmitted to the respiratory system over time that may better capture risk for ventilator-induced lung injury than individual ventilator management components. We sought to evaluate if mechanical ventilation management with a high mechanical power is associated with fewer ventilator-free days (VFD) in children with pediatric acute respiratory distress syndrome (PARDS). Methods: Retrospective analysis of a prospective observational international cohort study. Results: There were 306 children from 55 pediatric intensive care units included. High mechanical power was associated with younger age, higher oxygenation index, a comorbid condition of bronchopulmonary dysplasia, higher tidal volume, higher delta pressure (peak inspiratory pressure—positive end-expiratory pressure), and higher respiratory rate. Higher mechanical power was associated with fewer 28-day VFD after controlling for confounding variables (per 0.1 J·min−1·Kg−1 Subdistribution Hazard Ratio (SHR) 0.93 (0.87, 0.98), p = 0.013). Higher mechanical power was not associated with higher intensive care unit mortality in multivariable analysis in the entire cohort (per 0.1 J·min−1·Kg−1 OR 1.12 [0.94, 1.32], p = 0.20). But was associated with higher mortality when excluding children who died due to neurologic reasons (per 0.1 J·min−1·Kg−1 OR 1.22 [1.01, 1.46], p = 0.036). In subgroup analyses by age, the association between higher mechanical power and fewer 28-day VFD remained only in children < 2-years-old (per 0.1 J·min−1·Kg−1 SHR 0.89 (0.82, 0.96), p = 0.005). Younger children were managed with lower tidal volume, higher delta pressure, higher respiratory rate, lower positive end-expiratory pressure, and higher PCO2 than older children. No individual ventilator management component mediated the effect of mechanical power on 28-day VFD. Conclusions: Higher mechanical power is associated with fewer 28-day VFDs in children with PARDS. This association is strongest in children < 2-years-old in whom there are notable differences in mechanical ventilation management. While further validation is needed, these data highlight that ventilator management is associated with outcome in children with PARDS, and there may be subgroups of children with higher potential benefit from strategies to improve lung-protective ventilation. Take Home Message: Higher mechanical power is associated with fewer 28-day ventilator-free days in children with pediatric acute respiratory distress syndrome. This association is strongest in children <2-years-old in whom there are notable differences in mechanical ventilation management. © 2021, The Author(s).Ítem Morphological Differences between Patient Self-inflicted and Ventilator-induced Lung Injury: An Experimental Study(2023-03) Cruces, Pablo; Erranz, Benjamín; Carlos, González,; Diaz, FrancoÍtem Progression of regional lung strain and heterogeneity in lung injury: assessing the evolution under spontaneous breathing and mechanical ventilation(Springer, 2020-12) Hurtado, Daniel E.; Erranz, Benjamín; Lillo, Felipe; Sarabia-Vallejos, Mauricio; Iturrieta, Pablo; Morales, Felipe; Blaha, Katherine; Medina, Tania; Diaz, Franco; Cruces, PabloBackground: Protective mechanical ventilation (MV) aims at limiting global lung deformation and has been associ‑ ated with better clinical outcomes in acute respiratory distress syndrome (ARDS) patients. In ARDS lungs without MV support, the mechanisms and evolution of lung tissue deformation remain understudied. In this work, we quantify the progression and heterogeneity of regional strain in injured lungs under spontaneous breathing and under MV. Methods: Lung injury was induced by lung lavage in murine subjects, followed by 3 h of spontaneous breathing (SB-group) or 3 h of low Vt mechanical ventilation (MV-group). Micro-CT images were acquired in all subjects at the beginning and at the end of the ventilation stage following induction of lung injury. Regional strain, strain progres‑ sion and strain heterogeneity were computed from image-based biomechanical analysis. Three-dimensional regional strain maps were constructed, from which a region-of-interest (ROI) analysis was performed for the regional strain, the strain progression, and the strain heterogeneity. Results: After 3 h of ventilation, regional strain levels were signifcantly higher in 43.7% of the ROIs in the SB-group. Signifcant increase in regional strain was found in 1.2% of the ROIs in the MV-group. Progression of regional strain was found in 100% of the ROIs in the SB-group, whereas the MV-group displayed strain progression in 1.2% of the ROIs. Progression in regional strain heterogeneity was found in 23.4% of the ROIs in the SB-group, while the MV-group resulted in 4.7% of the ROIs showing signifcant changes. Deformation progression is concurrent with an increase of non-aerated compartment in SB-group (from 13.3%±1.6% to 37.5%±3.1%), being higher in ventral regions of the lung. Conclusions: Spontaneous breathing in lung injury promotes regional strain and strain heterogeneity progression. In contrast, low Vt MV prevents regional strain and heterogeneity progression in injured lungs.Ítem The renal compartment: a hydraulic view(SpringerOpen, 2014) Cruces, Pablo; Salas, Camila; Lillo, Pablo; Salomon, Tatiana; Lillo, Felipe; Hurtado, Daniel EBackground: The hydraulic behavior of the renal compartment is poorly understood. In particular, the role of the renal capsule on the intrarenal pressure has not been thoroughly addressed to date. We hypothesized that pressure and volume in the renal compartment are not linearly related, similar to other body compartments. Methods: The pressure-volume curve of the renal compartment was obtained by injecting fluid into the renal pelvis and recording the rise in intrarenal pressure in six anesthetized and mechanically ventilated piglets, using a catheter Camino 4B® inserted into the renal parenchyma. Results: In healthy kidneys, pressure has a highly nonlinear dependence on the injected volume, as revealed by an exponential fit to the data (R2 = 0.92). On the contrary, a linear relation between pressure and volume is observed in decapsulated kidneys. We propose a biomechanical model for the renal capsule that is able to explain the nonlinear pressure-volume dependence for moderate volume increases. Conclusions: We have presented experimental evidence and a theoretical model that supports the existence of a renal compartment. The mechanical role of the renal capsule investigated in this work may have important implications in elucidating the role of decompressive capsulotomy in reducing the intrarenal pressure in acutely injured kidneys. © 2014, Cruces et al.; licensee Springer.Ítem Ventilatory load reduction by combined mild hypothermia and ultraprotective mechanical ventilation strategy in severe COVID-19-related acute respiratory distress syndrome: A physiological study(Wolters Kluwer Medknow Publications, 2024-04) Cruces, Pablo; Moreno, Diego; Reveco, Sonia; Ramírez, Yenny; Díaz, FrancoWe report the feasibility of a combined approach of very low low tidal volume (VT) and mild therapeutic hypothermia (MTH) to decrease the ventilatory load in a severe COVID-19-related acute respiratory distress syndrome (ARDS) cohort. Inclusion criteria was patients ≥18-years-old, severe COVID-19-related ARDS, driving pressure ΔP >15 cmH2O despite low-VT strategy, and extracorporeal therapies not available. MTH was induced with a surface cooling device aiming at 34°C. MTH was maintained for 72 h, followed by rewarming of 1°C per day. Data were shown in median (interquartile range, 25%-75%). Mixed effects analysis and Dunnett s test were used for comparisons. Seven patients were reported. Ventilatory load decreased during the first 24 h, minute ventilation (VE) decreased from 173 (170-192) to 152 (137-170) mL/kg/min (P = 0.007), and mechanical power (MP) decreased from 37 (31-40) to 29 (26-34) J/min (P = 0.03). At the end of the MTH period, the VT, P, and plateau pressure remained consistently close to 3.9 mL/kg predicted body weight, 12 and 26 cmH2O, respectively. A combined strategy of MTH and ultraprotective mechanical ventilation (MV) decreased VE and MP in severe COVID-19-related ARDS. The decreasing of ventilatory load may allow maintaining MV within safety thresholds. © 2024 Turkish Journal of Emergency Medicine.