Browsing by Author "Bruhn, A."

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    A Protective Ventilation Approach Results in Reverse Triggering Dyssynchrony in an Experimental Model of Acute Lung Injury
    (AMER THORACIC SOC, 2020) Damiani, F.; Engelberts, D.; Bastia, L.; Osada, K.; Katira, B. H.; Otulakowski, G.; Goligher, E. C.; Reid, W.; Bruhn, A.; Brochard, L. J.
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    Decreasing tidal volume from 6 to 4 ml/kg: feasibility and effects on repeated opening and closing
    (2010) Retamal, J.; Libuy Mena, Javiera Camila; Jimenez, M.; Delgado, M.; Besa, C.; Bugedo, G.; Bruhn, A.
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    Early rise in central venous pressure during a spontaneous breathing trial: A promising test to identify patients at high risk of weaning failure?
    (2019) Dubo, S.; Valenzuela, E.D.; Aquevedo, A.; Jibaja, M.; Berrutti, D.; Labra, C.; Lagos, R.; García, M.F.; Ramírez, V.; Tobar, M.; Picoita, F.; Peláez, C.; Carpio, D.; Alegría, L.; Hidalgo, C.; Godoy, K.; Bruhn, A.; Hernández, G.; Bakker, J.; Castro, R.
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    Is Gamma (P.1) Variant Associated with a Higher Severity in ICU Patients with SARS-CoV-2 Infection
    (2022) Vera, M.; Angulo, J.; Medina, R.; Ferres, M.; Bruhn, A.; Castro, R.; Pardo-Roa, C.
    The Omicron variant of SARS-CoV-2 has been shown to evade neutralizing antibodies elicited by vaccination or infection. Despite the global spread of the Omicron variant, even among highly vaccinated populations, death rates have not increased concomitantly. These data suggest that immune mechanisms beyond antibody-mediated virus neutralization may protect against severe disease. In addition to neutralizing pathogens, antibodies contribute to control and clearance of infections through Fc effector mechanisms. Here, we probed the ability of vaccine-induced antibodies to drive Fc effector activity against the Omicron variant using samples from individuals receiving one of three SARS-CoV-2 vaccines. Despite a substantial loss of IgM, IgA, and IgG binding to the Omicron variant receptor binding domain (RBD) in samples from individuals receiving BNT162b2, mRNA-1273, and CoronaVac vaccines, stable binding was maintained against the full-length Omicron Spike protein. Compromised RBD binding IgG was accompanied by a loss of RBD-specific antibody Fc gamma receptor (Fe gamma R) binding in samples from individuals who received the CoronaVac vaccine, but RBD-specific Fc gamma R2a and Fc gamma R3a binding was preserved in recipients of mRNA vaccines. Conversely, Spike protein-specific antibodies exhibited persistent but reduced binding to Fc gamma Rs across all three vaccines, although higher binding was observed in samples from recipients of mRNA vaccines. This was associated with preservation of Fc gamma R2a and Fc gamma R3a binding antibodies and maintenance of Spike protein-specific antibody-dependent natural killer cell activation. Thus, despite the loss of Omicron neutralization, vaccine-induced Spike protein-specific antibodies continue to drive Fc effector functions, suggesting a capacity for extraneutralizing antibodies to contribute to disease control.
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    Tidal volume is a major determinant of cyclic recruitment-derecruitment in acute respiratory distress syndrome
    (EDIZIONI MINERVA MEDICA, 2011) Bruhn, A.; Bugedo, D.; Riquelme, F.; Varas, J.; Retamal, J.; Besa, C.; Cabrera, C.; Bugedo, G.
    Background. Overdistension and cyclic recruitment-derecruitment contribute to ventilator-induced lung injury. High tidal volumes are thought to increase mortality mainly by inducing overdistension. However, experimental evidence suggests that tidal volume (VT) may also influence cyclic recruitment-derecruitment. Our main goal was to determine whether high tidal volumes increase cyclic recruitment-derecruitment in acute respiratory distress syndrome (ARDS) patients, as measured by dynamic computed tomography (CT).