Browsing by Author "Bugedo Tarraza, Guillermo Jaime"

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    Acute lung injury secondary to hydrochloric acid instillation induces small airway hyperresponsiveness
    (2021) Basoalto Escobar, Roque Ignacio; Damiani Rebolledo, Luis Felipe; Bachmann Barron, María Consuelo; Fonseca, Marcelo; Barros, Marisol; Soto Muñoz, Dagoberto Igor; Araos, Joaquin; Jalil Contreras, Yorschua Frederick; Dubo, Sebastian; Retamal, Jaime; Bugedo Tarraza, Guillermo Jaime; Henriquez, Mauricio; Bruhn Cruz, Alejandro Rodrigo
    Background: Acute respiratory distress syndrome (ARDS) is a severe form of respiratory failure characterized by altered lung mechanics and poor oxygenation. Bronchial hyperresponsiveness has been reported in ARDS survivors and animal models of acute lung injury. Whether this hyperreactivity occurs at the small airways or not is unknown. Objective: To determine ex-vivo small airway reactivity in a rat model of acute lung injury (ALI) by hydrochloric acid (HCl) instillation. Methods: Twelve anesthetized rats were connected to mechanical ventilation for 4-hour, and randomly allocated to either ALI group (HCl intratracheal instillation; n=6) or Sham (intratracheal instillation of 0.9% NaCl; n=6). Oxygenation was assessed by arterial blood gases. After euthanasia, tissue samples from the right lung were harvested for histologic analysis and wet-dry weight ratio assessment. Precision cut lung slice technique (100-200 pm diameter) was applied in the left lung to evaluate ex vivo small airway constriction in response to histamine and carbachol stimulation, using phase-contrast video microscopy. Results: Rats from the ALI group exhibited hypoxemia, worse histologic lung injury, and increased lung wet-dry weight ratio as compared with the sham group. The bronchoconstrictor responsiveness was significantly higher in the ALI group, both for carbachol (maximal contraction of 84.5 +/- 2.5% versus 61.4 +/- 4.2% in the Sham group, P<0.05), and for histamine (maximal contraction of 78.6 +/- 5.3% versus 49.6 +/- 5.3% in the Sham group, P<0.05). Conclusion: In an animal model of acute lung injury secondary to HCL instillation, small airway hyperresponsiveness to carbachol and histamine is present. These results may provide further insight into the pathophysiologi of ARDS.
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    Beta-Lactam Antibiotics Can Be Measured in the Exhaled Breath Condensate in Mechanically Ventilated Patients: a Pilot Study
    (2023) Escalona Solari, José Antonio; Soto Muñoz, Dagoberto Igor; Oviedo Álvarez, Vanessa Andrea; Rivas Garrido, Elizabeth Alexis; Severino, Nicolás; Kattan Tala, Eduardo José; Andresen Hernández, Max Alfonso; Bravo Morales, Sebastián Ignacio; Basoalto Escobar, Roque Ignacio; Bachmann Barron, María Consuelo; Kwok-Yin, Wong; Pavez, Nicolás; Bruhn Cruz, Alejandro Rodrigo; Bugedo Tarraza, Guillermo Jaime; Retamal Montes, Jaime Alejandro
    Different techniques have been proposed to measure antibiotic levels within the lung parenchyma; however, their use is limited because they are invasive and associated with adverse effects. We explore whether beta-lactam antibiotics could be measured in exhaled breath condensate collected from heat and moisture exchange filters (HMEFs) and correlated with the concentration of antibiotics measured from bronchoalveolar lavage (BAL). We designed an observational study in patients undergoing mechanical ventilation, which required a BAL to confirm or discard the diagnosis of pneumonia. We measured and correlated the concentration of beta-lactam antibiotics in plasma, epithelial lining fluid (ELF), and exhaled breath condensate collected from HMEFs. We studied 12 patients, and we detected the presence of antibiotics in plasma, ELF, and HMEFs from every patient studied. The concentrations of antibiotics were very heterogeneous over the population studied. The mean antibiotic concentration was 293.5 (715) ng/mL in plasma, 12.3 (31) ng/mL in ELF, and 0.5 (0.9) ng/mL in HMEF. We found no significant correlation between the concentration of antibiotics in plasma and ELF (R2 = 0.02, p = 0.64), between plasma and HMEF (R2 = 0.02, p = 0.63), or between ELF and HMEF (R2 = 0.02, p = 0.66). We conclude that beta-lactam antibiotics can be detected and measured from the exhaled breath condensate accumulated in the HMEF from mechanically ventilated patients. However, no correlations were observed between the antibiotic concentrations in HMEF with either plasma or ELF.
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    Mechanical Power of Ventilation: From Computer to Clinical Implications
    (2023) Damiani Rebolledo, L. Felipe; Basoalto Escobar, Roque Ignacio; Retamal Montes, Jaime Alejandro; Bruhn Cruz, Alejandro Rodrigo; Bugedo Tarraza, Guillermo Jaime
    Mechanical ventilation is a lifesaving intervention that may also induce further lung injury by exerting excessive mechanical forces on susceptible lung tissue, a phenomenon termed ventilator-induced lung injury (VILI). The concept of mechanical power (MP) aims to unify in one single variable the contribution of the different ventilatory parameters that could induce VILI by measuring the energy transfer to the lung over time. Despite an increasing amount of evidence demonstrating that high MP values can be associated with VILI development in experimental studies, the evidence regarding the association of MP and clinical outcomes remains controversial. In the present review, we describe the different determinants of VILI, the concept and computation of MP, and discuss the experimental and clinical studies related to MP. Currently, due to different limitations, the clinical application of MP is debatable. Further clinical studies are required to enhance our understanding of the relationship between MP and the development of VILI, as well as its potential impact on clinical outcomes.