Examinando por Autor "Bruhn, Alejandro"

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    Physiological and clinical effects of trunk inclination adjustment in patients with respiratory failure: a scoping review and narrative synthesis
    (BMC, 2024-07-09) Benites, Martín Hernán; Zapata‑Canivilo, Marcelo; Poblete, Fabian; Labbe, Francisco; Battiato, Romina; Ferre, Andrés; Dreyse, Jorge; Bugedo, Guillermo; Bruhn, Alejandro; Costa, Eduardo L. V.; Retamal, Jaime
    Background Adjusting trunk inclination from a semirecumbent position to a supinefat position or vice versa in patients with respiratory failure signifcantly afects numerous aspects of respiratory physiology including respiratory mechanics, oxygenation, endexpiratory lung volume, and ventilatory efciency. Despite these observed efects, the current clinical evidence regarding this positioning manoeuvre is limited. This study undertakes a scoping review of patients with respiratory failure undergoing mechanical ventilation to assess the efect of trunk inclination on physiological lung parameters. Methods The PubMed, Cochrane, and Scopus databases were systematically searched from 2003 to 2023. Interventions: Changes in trunk inclination. Measurements: Four domains were evaluated in this study: 1) respiratory mechanics, 2) ventilation distribution, 3) oxygenation, and 4) ventilatory efciency. Results After searching the three databases and removing duplicates, 220 studies were screened. Of these, 37 were assessed in detail, and 13 were included in the fnal analysis, comprising 274 patients. All selected studies were experimental, and assessed respiratory mechanics, ventilation distribution, oxygenation, and ventilatory efciency, primarily within 60 min post postural change. Conclusion In patients with acute respiratory failure, transitioning from a supine to a semirecumbent position leads to decreased respiratory system compliance and increased airway driving pressure. Additionally, CARDS patients experienced an improvement in ventilatory efciency, which resulted in lower PaCO2 levels. Improvements in oxygenation were observed in a few patients and only in those who exhibited an increase in EELV upon moving to a semi recumbent position. Therefore, the trunk inclination angle must be accurately reported in patients with respiratory failure under mechanical ventilation
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    Spontaneous breathing promotes lung injury in an experimental model of alveolar collapse
    (Springer Nature, 2022) Bachmann, María Consuelo; Cruces, Pablo; Díaz, Franco; Oviedo, Vanessa; Goich, Mariela; Fuenzalida, José; Damiani, Luis Felipe; Basoalto, Roque; Jalil, Yorschua; Carpio, David; Hamidi Vadeghani, Niki; Cornejo, Rodrigo; Rovegno, Maximiliano; Bugedo, Guillermo; Bruhn, Alejandro; Retamal, Jaime
    Vigorous spontaneous breathing has emerged as a promotor of lung damage in acute lung injury, an entity known as “patient self-inflicted lung injury”. Mechanical ventilation may prevent this second injury by decreasing intrathoracic pressure swings and improving regional air distribution. Therefore, we aimed to determine the effects of spontaneous breathing during the early stage of acute respiratory failure on lung injury and determine whether early and late controlled mechanical ventilation may avoid or revert these harmful effects. A model of partial surfactant depletion and lung collapse was induced in eighteen intubated pigs of 32 ±4 kg. Then, animals were randomized to (1) SB‐group: spontaneous breathing with very low levels of pressure support for the whole experiment (eight hours), (2) Early MV-group: controlled mechanical ventilation for eight hours, or (3) Late MV-group: first half of the experiment on spontaneous breathing (four hours) and the second half on controlled mechanical ventilation (four hours). Respiratory, hemodynamic, and electric impedance tomography data were collected. After the protocol, animals were euthanized, and lungs were extracted for histologic tissue analysis and cytokines quantification. SB-group presented larger esophageal pressure swings, progressive hypoxemia, lung injury, and more dorsal and inhomogeneous ventilation compared to the early MV-group. In the late MV-group switch to controlled mechanical ventilation improved the lung inhomogeneity and esophageal pressure swings but failed to prevent hypoxemia and lung injury. In a lung collapse model, spontaneous breathing is associated to large esophageal pressure swings and lung inhomogeneity, resulting in progressive hypoxemia and lung injury. Mechanical ventilation prevents these mechanisms of patient self-inflicted lung injury if applied early, before spontaneous breathing occurs, but not when applied late