Browsing by Author "Oviedo, Vanessa"
Now showing 1 - 5 of 5
Results Per Page
Sort Options
- ItemDevelopment of mechanical ventilators in Chile. Chronicle of the initiative "Un Respiro para Chile(2022) Bugedo, Guillermo; Tobar, Eduardo; Alegria, Leyla; Oviedo, Vanessa; Arellano, Daniel; Basoalto, Roque; Enberg, Luis; Suarez, Pablo; Bitran, Eduardo; Chabert, Steren; Bruhn, AlejandroAt the beginning of the COVID-19 pandemic in Chile, in March 2020, a projection indicated that a significant group of patients with pneumonia would require admission to an Intensive Care Unit and connection to a mechanical ventilator. Therefore, a paucity of these devices and other supplies was predicted. The initiative "Un respiro para Chile" brought together many people and institutions, public and private. In the course of three months, it allowed the design and building of several ventilatory assistance devices, which could be used in critically ill patients.
- ItemExploring the relationship between capillary refill time, skin blood flow and microcirculatory reactivity during early resuscitation of patients with septic shock: a pilot study(2023) Contreras, Roberto; Hernandez, Glenn; Daniel Valenzuela, Emilio; Gonzalez, Cecilia; Ulloa, Rodrigo; Soto, Dagoberto; Castro, Ricardo; Guzman, Camila; Oviedo, Vanessa; Alegria, Leyla; Vidal, Diego; Morales, Sebastian; Adolfo Ospina-Tascon, Gustavo; Bakker, Jan; Kattan, EduardoCapillary refill time (CRT), a costless and widely available tool, has emerged as a promising target to guide septic shock resuscitation. However, it has yet to gain universal acceptance due to its potential inter-observer variability. Standardization of CRT assessment may minimize this problem, but few studies have compared this approach with techniques that directly assess skin blood flow (SBF). Our objective was to determine if an abnormal CRT is associated with impaired SBF and microvascular reactivity in early septic shock patients. Twelve septic shock patients were subjected to multimodal perfusion and hemodynamic monitoring for 24 h. Three time-points (0, 1, and 24 h) were registered for each patient. SBF was measured by laser doppler. We performed a baseline SBF measurement and two microvascular reactivity tests: one with a thermal challenge at 44 & DEG;C and other with a vascular occlusion test. Ten healthy volunteers were evaluated to obtain reference values. The patients (median age 70 years) exhibited a 28-day mortality of 50%. Baseline CRT was 3.3 [2.7-7.3] seconds. In pooled data analysis, abnormal CRT presented a significantly lower SBF when compared to normal CRT [44 (13.3-80.3) vs 193.2 (99.4-285) APU, p = 0.0001]. CRT was strongly associated with SBF (R-2 0.76, p < 0.0001). An abnormal CRT also was associated with impaired thermal challenge and vascular occlusion tests. Abnormal CRT values observed during early septic shock resuscitation are associated with impaired skin blood flow, and abnormal skin microvascular reactivity. Future studies should confirm these results.
- ItemPhysiological effects of high-flow nasal cannula oxygen therapy after extubation: a randomized crossover study(2023) Basoalto Escobar, Roque Ignacio; Damiani Rebolledo, L. Felipe; Jalil, Yorschua; Bachmann, María Consuelo; Oviedo, Vanessa; Alegría Vargas, Leyla; Valenzuela, Emilio Daniel; Rovegno Echavarria, Maxiliano; Ruiz-Rudolph, Pablo; Cornejo, Rodrigo; Retamal Montes, Jaime; Bugedo Tarraza, Guillermo; Thille, Arnaud W.; Bruhn, AlejandroAbstract: Background: Prophylactic high-flow nasal cannula (HFNC) oxygen therapy can decrease the risk of extubation failure. It is frequently used in the postextubation phase alone or in combination with noninvasive ventilation. However, its physiological effects in this setting have not been thoroughly investigated. The aim of this study was to determine comprehensively the effects of HFNC applied after extubation on respiratory effort, diaphragm activity, gas exchange, ventilation distribution, and cardiovascular biomarkers. Methods: This was a prospective randomized crossover physiological study in critically ill patients comparing 1 h of HFNC versus 1 h of standard oxygen after extubation. The main inclusion criteria were mechanical ventilation for at least 48 h due to acute respiratory failure, and extubation after a successful spontaneous breathing trial (SBT). We measured respiratory effort through esophageal/transdiaphragmatic pressures, and diaphragm electrical activity (ΔEAdi). Lung volumes and ventilation distribution were estimated by electrical impedance tomography. Arterial and central venous blood gases were analyzed, as well as cardiac stress biomarkers. Results: We enrolled 22 patients (age 59 ± 17 years; 9 women) who had been intubated for 8 ± 6 days before extubation. Respiratory effort was significantly lower with HFNC than with standard oxygen therapy, as evidenced by esophageal pressure swings (5.3 [4.2–7.1] vs. 7.2 [5.6–10.3] cmH2O; p < 0.001), pressure–time product (85 [67–140] vs. 156 [114–238] cmH2O*s/min; p < 0.001) and ΔEAdi (10 [7–13] vs. 14 [9–16] µV; p = 0.022). In addition, HFNC induced increases in end-expiratory lung volume and PaO2/FiO2 ratio, decreases in respiratory rate and ventilatory ratio, while no changes were observed in systemic hemodynamics, Troponin T, or in amino-terminal pro-B-type natriuretic peptide. Conclusions: Prophylactic application of HFNC after extubation provides substantial respiratory support and unloads respiratory muscles.
- ItemReduction of Respiratory Rate in COVID-19-Associated ARDS(2022) Damiani, L. Felipe; Oviedo, Vanessa; Alegria, Leyla; Soto, Dagoberto; Basoalto, Roque; Consuelo Bachmann, M.; Jalil Contreras, Yorschua Frederick; Santis, Cesar; Vera, Magdalena; Retamal, Jaime; Bruhn, Alejandro; Bugedo, Guillermo
- ItemSpontaneous breathing promotes lung injury in an experimental model of alveolar collapse(2022) Bachmann, María Consuelo; Cruces, Pablo; Díaz, Franco; Oviedo, Vanessa; Goich, Mariela; Fuenzalida, José; Damiani Rebolledo, L. Felipe; Basoalto, Roque; Jalil, Yorschua F.; Carpio Cordero, David; Hamidi Vadeghani, Niki; Cornejo, Rodrigo; Rovegno Echavarria, Maximiliano; Bugedo Tarraza, Guillermo; Bruhn, Alejandro; Retamal Montes, JaimeVigorous 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.