Browsing by Author "Ruiz-Rudolph, Pablo"

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    Inflammatory biomarkers and pendelluft magnitude in ards patients transitioning from controlled to partial support ventilation
    (2022) Cornejo, Rodrigo A.; Arellano, Daniel H.; Ruiz-Rudolph, Pablo; Guinez, Dannette, V; Morais, Caio C. A.; Gajardo, Abraham I. J.; Lazo, Marioli T.; Brito, Roberto E.; Cerda, Maria A.; Gonzalez, Sedric J.; Rojas, Veronica A.; Diaz, Gonzalo A.; Lopez, Lorena D. M.; Medel, Juan N.; Soto, Dagoberto, I; Bruhn, Alejandro R.; Amato, Marcelo B. P.; Estuardo, Nivia R.
    The transition from controlled to partial support ventilation is a challenge in acute respiratory distress syndrome (ARDS) patients due to the risks of patient-self-inflicted lung injury. The magnitude of tidal volume (V-T) and intrapulmonary dyssynchrony (pendelluft) are suggested mechanisms of lung injury. We conducted a prospective, observational, physiological study in a tertiary academic intensive care unit. ARDS patients transitioning from controlled to partial support ventilation were included. On these, we evaluated the association between changes in inflammatory biomarkers and esophageal pressure swing (Delta P-es), transpulmonary driving pressure (Delta P-L), V-T, and pendelluft. Pendelluft was defined as the percentage of the tidal volume that moves from the non-dependent to the dependent lung region during inspiration, and its frequency at different thresholds (- 15, - 20 and - 25%) was also registered. Blood concentrations of inflammatory biomarkers (IL-6, IL-8, TNF-alpha, ANGPT2, RAGE, IL-18, Caspase-1) were measured before (T-0) and after 4-h (T-4) of partial support ventilation. Pendelluft, Delta P-es, Delta P-L and V-T were recorded. Nine out of twenty-four patients (37.5%) showed a pendelluft mean >= 10%. The mean values of Delta P-es, Delta P-L, and V-T were - 8.4 [- 6.7; - 10.2] cmH(2)O, 15.2 [12.3-16.5] cmH(2)O and 8.1 [7.3-8.9] m/kg PBW, respectively. Significant associations were observed between the frequency of high-magnitude pendelluft and IL-8, IL-18, and Caspase-1 changes (T-0/T-4 ratio). These results suggest that the frequency of high magnitude pendelluft may be a potential determinant of inflammatory response related to inspiratory efforts in ARDS patients transitioning to partial support ventilation. Future studies are needed to confirm these results.
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    Pendelluft in hypoxemic patients resuming spontaneous breathing: proportional modes versus pressure support ventilation
    (2023) Arellano, Daniel H.; Brito, Roberto; Morais, Caio C. A.; Ruiz-Rudolph, Pablo; Gajardo, Abraham I. J.; Guiñez, Dannette V.; Lazo, Marioli T.; Ramirez, Ivan; Rojas, Verónica A.; Bruhn, Alejandro; Cerda, María A.; Medel, Juan N.; Illanes, Victor; Estuardo, Nivia R.; Brochard, Laurent J.; Amato, Marcelo B. P.; Cornejo, Rodrigo A.
    Background: Internal redistribution of gas, referred to as pendelluft, is a new potential mechanism of effort-dependent lung injury. Neurally-adjusted ventilatory assist (NAVA) and proportional assist ventilation (PAV +) follow the patient’s respiratory effort and improve synchrony compared with pressure support ventilation (PSV). Whether these modes could prevent the development of pendelluft compared with PSV is unknown. We aimed to compare pendelluft magnitude during PAV + and NAVA versus PSV in patients with resolving acute respiratory distress syndrome (ARDS). Methods: Patients received either NAVA, PAV + , or PSV in a crossover trial for 20-min using comparable assistance levels after controlled ventilation (> 72 h). We assessed pendelluft (the percentage of lost volume from the non-dependent lung region displaced to the dependent region during inspiration), drive (as the delta esophageal swing of the first 100 ms [ΔPes 100 ms]) and inspiratory effort (as the esophageal pressure–time product per minute [PTPmin]). We performed repeated measures analysis with post-hoc tests and mixed-effects models. Results: Twenty patients mechanically ventilated for 9 [5–14] days were monitored. Despite matching for a similar tidal volume, respiratory drive and inspiratory effort were slightly higher with NAVA and PAV + compared with PSV (ΔPes 100 ms of –2.8 [−3.8–−1.9] cm H2O, −3.6 [−3.9–−2.4] cm H2O and −2.1 [−2.5–−1.1] cm H2O, respectively, p < 0.001 for both comparisons; PTPmin of 155 [118–209] cm H2O s/min, 197 [145–269] cm H2O s/min, and 134 [93–169] cm H2O s/min, respectively, p < 0.001 for both comparisons). Pendelluft magnitude was higher in NAVA (12 ± 7%) and PAV + (13 ± 7%) compared with PSV (8 ± 6%), p < 0.001. Pendelluft magnitude was strongly associated with respiratory drive (β = -2.771, p-value < 0.001) and inspiratory effort (β = 0.026, p  < 0.001), independent of the ventilatory mode. A higher magnitude of pendelluft in proportional modes compared with PSV existed after adjusting for PTPmin (β = 2.606, p = 0.010 for NAVA, and β = 3.360, p = 0.004 for PAV +), and only for PAV + when adjusted for respiratory drive (β = 2.643, p = 0.009 for PAV +). Conclusions: Pendelluft magnitude is associated with respiratory drive and inspiratory effort. Proportional modes do not prevent its occurrence in resolving ARDS compared with PSV.
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    Physiological 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, Alejandro
    Abstract: 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.
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    Reduced repressive epigenetic marks, increased DNA damage and Alzheimer's disease hallmarks in the brain of humans and mice exposed to particulate urban air pollution
    (2020) Calderon-Garciduenas, Lilian; Herrera-Soto, Andrea; Jury, Nur; Maher, Barbara A.; Gonzalez-Maciel, Angelica; Reynoso-Robles, Rafael; Ruiz-Rudolph, Pablo; van Zundert, Brigitte; Varela-Nallar, Lorena
    Exposure to air pollutants is associated with an increased risk of developing Alzheimer's disease (AD). AD pathological hallmarks and cognitive deficits are documented in children and young adults in polluted cities (e.g. Metropolitan Mexico City, MMC). Iron-rich combustion- and friction-derived nanoparticles (CFDNPs) that are abundantly present in airborne particulate matter pollution have been detected in abundance in the brains of young urbanites. Epigenetic gene regulation has emerged as a candidate mechanism linking exposure to air pollution and brain diseases. A global decrease of the repressive histone post-translational modifications (HPTMs) H3K9me2 and H3K9me3 (H3K9me2/me3) has been described both in AD patients and animal models. Here, we evaluated nuclear levels of H3K9me2/me3 and the DNA double-strand-break marker gamma-H2AX by immunostaining in post-mortem prefrontal white matter samples from 23 young adults (age 29 +/- 6 years) who resided in MMC (n = 13) versus low-pollution areas (n = 10). Lower H3K9me2/me3 and higher gamma-H2A.X staining were present in MMC urbanites, who also displayed the presence of hyperphosphorylated tau and amyloid-beta (A beta) plaques. Transmission electron microscopy revealed abundant CFDNPs in neuronal, glial and endothelial nuclei in MMC residents' frontal samples. In addition, mice exposed to particulate air pollution (for 7 months) in urban Santiago (Chile) displayed similar brain impacts; reduced H3K9me2/me3 and increased gamma-H2A.X staining, together with increased levels of AD-related tau phosphorylation. Together, these findings suggest that particulate air pollution, including metal-rich CFDNPs, impairs brain chromatin silencing and reduces DNA integrity, increasing the risk of developing AD in young individuals exposed to high levels of particulate air pollution.