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Quiros KAM, Nelson TM, Ulu A, Dominguez EC, Biddle TA, Lo DD, Nordgren TM, Eskandari M. A Comparative Study of Ex-Vivo Murine Pulmonary Mechanics Under Positive- and Negative-Pressure Ventilation. Ann Biomed Eng 2024; 52:342-354. [PMID: 37906375 PMCID: PMC10808462 DOI: 10.1007/s10439-023-03380-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 10/03/2023] [Indexed: 11/02/2023]
Abstract
Increased ventilator use during the COVID-19 pandemic resurrected persistent questions regarding mechanical ventilation including the difference between physiological and artificial breathing induced by ventilators (i.e., positive- versus negative-pressure ventilation, PPV vs NPV). To address this controversy, we compare murine specimens subjected to PPV and NPV in ex vivo quasi-static loading and quantify pulmonary mechanics via measures of quasi-static and dynamic compliances, transpulmonary pressure, and energetics when varying inflation frequency and volume. Each investigated mechanical parameter yields instance(s) of significant variability between ventilation modes. Most notably, inflation compliance, percent relaxation, and peak pressure are found to be consistently dependent on the ventilation mode. Maximum inflation volume and frequency note varied dependencies contingent on the ventilation mode. Contradictory to limited previous clinical investigations of oxygenation and end-inspiratory measures, the mechanics-focused comprehensive findings presented here indicate lung properties are dependent on loading mode, and importantly, these dependencies differ between smaller versus larger mammalian species despite identical custom-designed PPV/NPV ventilator usage. Results indicate that past contradictory findings regarding ventilation mode comparisons in the field may be linked to the chosen animal model. Understanding the differing fundamental mechanics between PPV and NPV may provide insights for improving ventilation strategies and design to prevent associated lung injuries.
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Affiliation(s)
- K A M Quiros
- Department of Mechanical Engineering, University of California Riverside, 900 University Ave., Riverside, CA, 92506, USA
| | - T M Nelson
- Department of Mechanical Engineering, University of California Riverside, 900 University Ave., Riverside, CA, 92506, USA
| | - A Ulu
- Division of Biomedical Sciences, Riverside School of Medicine, University of California, Riverside, CA, USA
| | - E C Dominguez
- Division of Biomedical Sciences, Riverside School of Medicine, University of California, Riverside, CA, USA
- Environmental Toxicology Graduate Program, University of California, Riverside, CA, USA
| | - T A Biddle
- Division of Biomedical Sciences, Riverside School of Medicine, University of California, Riverside, CA, USA
- Environmental Toxicology Graduate Program, University of California, Riverside, CA, USA
- School of Medicine, BREATHE Center, University of California, Riverside, CA, USA
| | - D D Lo
- Division of Biomedical Sciences, Riverside School of Medicine, University of California, Riverside, CA, USA
- School of Medicine, BREATHE Center, University of California, Riverside, CA, USA
- Center for Health Disparities Research, University of California, Riverside, CA, USA
| | - T M Nordgren
- Division of Biomedical Sciences, Riverside School of Medicine, University of California, Riverside, CA, USA
- Environmental Toxicology Graduate Program, University of California, Riverside, CA, USA
- School of Medicine, BREATHE Center, University of California, Riverside, CA, USA
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, USA
| | - M Eskandari
- Department of Mechanical Engineering, University of California Riverside, 900 University Ave., Riverside, CA, 92506, USA.
- School of Medicine, BREATHE Center, University of California, Riverside, CA, USA.
- Department of Bioengineering, University of California, Riverside, CA, USA.
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Nelson TM, Quiros KAM, Dominguez EC, Ulu A, Nordgren TM, Eskandari M. Diseased and healthy murine local lung strains evaluated using digital image correlation. Sci Rep 2023; 13:4564. [PMID: 36941463 PMCID: PMC10026788 DOI: 10.1038/s41598-023-31345-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 03/09/2023] [Indexed: 03/22/2023] Open
Abstract
Tissue remodeling in pulmonary disease irreversibly alters lung functionality and impacts quality of life. Mechanical ventilation is amongst the few pulmonary interventions to aid respiration, but can be harmful or fatal, inducing excessive regional (i.e., local) lung strains. Previous studies have advanced understanding of diseased global-level lung response under ventilation, but do not adequately capture the critical local-level response. Here, we pair a custom-designed pressure-volume ventilator with new applications of digital image correlation, to directly assess regional strains in the fibrosis-induced ex-vivo mouse lung, analyzed via regions of interest. We discuss differences between diseased and healthy lung mechanics, such as distensibility, heterogeneity, anisotropy, alveolar recruitment, and rate dependencies. Notably, we compare local and global compliance between diseased and healthy states by assessing the evolution of pressure-strain and pressure-volume curves resulting from various ventilation volumes and rates. We find fibrotic lungs are less-distensible, with altered recruitment behaviors and regional strains, and exhibit disparate behaviors between local and global compliance. Moreover, these diseased characteristics show volume-dependence and rate trends. Ultimately, we demonstrate how fibrotic lungs may be particularly susceptible to damage when contrasted to the strain patterns of healthy counterparts, helping to advance understanding of how ventilator induced lung injury develops.
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Affiliation(s)
- T M Nelson
- Department of Mechanical Engineering, University of California, Riverside, CA, USA
| | - K A M Quiros
- Department of Mechanical Engineering, University of California, Riverside, CA, USA
| | - E C Dominguez
- Division of Biomedical Sciences, Riverside School of Medicine, University of California, Riverside, CA, USA
- Environmental Toxicology Graduate Program, University of California Riverside, Riverside, CA, USA
| | - A Ulu
- Division of Biomedical Sciences, Riverside School of Medicine, University of California, Riverside, CA, USA
| | - T M Nordgren
- Division of Biomedical Sciences, Riverside School of Medicine, University of California, Riverside, CA, USA
- Environmental Toxicology Graduate Program, University of California Riverside, Riverside, CA, USA
- BREATHE Center, School of Medicine, University of California, Riverside, CA, USA
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, USA
| | - M Eskandari
- Department of Mechanical Engineering, University of California, Riverside, CA, USA.
- BREATHE Center, School of Medicine, University of California, Riverside, CA, USA.
- Department of Bioengineering, University of California, Riverside, CA, USA.
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Dotan Y, Shapiro WB, Male E, Dominguez EC, Aneja A, Huaqing Z, Dass C, Shenoy K, Marchetti N, Cordova FC, Criner GJ, Mamary AJ. Clinical predictors and explant lung pathology of acute exacerbation of idiopathic pulmonary fibrosis. ERJ Open Res 2020; 6:00261-2019. [PMID: 33043049 PMCID: PMC7533375 DOI: 10.1183/23120541.00261-2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 06/10/2020] [Indexed: 01/09/2023] Open
Abstract
Background Idiopathic pulmonary fibrosis (IPF) is characterised by constant threat of acute exacerbation of IPF (AE-IPF). It would be significant to identify risk factors of AE-IPF. We sought to determine the prognostic value of lung transplantation candidacy testing for AE-IPF and describe explant pathology of recipients with and without AE-IPF before lung transplantation. Methods Retrospective cohort study of 89 IPF patients listed for lung transplantation. Data included pulmonary function testing, echocardiography, right heart catheterisation, imaging, oesophageal pH/manometry and blood tests. Explanted tissue was evaluated by pulmonary pathologists and correlated to computed tomography (CT) findings. Results Out of 89 patients with IPF, 52 were transplanted during stable IPF and 37 had AE-IPF before transplantation (n=28) or death (n=9). There were no substantial differences in candidacy testing with and without AE-IPF. AE-IPF had higher rate of decline of forced vital capacity (FVC) (21±22% versus 4.8±14%, p=0.00019). FVC decline of >15% had a hazard ratio of 7.2 for developing AE-IPF compared to FVC decline of <5% (p=0.004). AE-IPF had more secondary diverse histopathology (82% versus 29%, p<0.0001) beyond diffuse alveolar damage. There was no correlation between ground-glass opacities (GGO) on chest CT at any point to development of AE-IPF (p=0.077), but GGO during AE-IPF predicted secondary pathological process beyond diffuse alveolar damage. Conclusions Lung transplantation candidacy testing including reflux studies did not predict AE-IPF besides FVC absolute decline. CT did not predict clinical or pathological AE-IPF. Secondary diverse lung pathology beyond diffuse alveolar damage was present in most AE-IPF, but not in stable IPF. Transplant candidacy testing fails to predict acute exacerbation of IPF besides FVC absolute decline. Patients transplanted during acute exacerbation of IPF reveal multiple secondary lung histopathological processes beyond the expected DAD.https://bit.ly/3e1CPjO
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Affiliation(s)
- Yaniv Dotan
- Dept of Thoracic Medicine and Surgery, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA
| | - William B Shapiro
- Dept of Thoracic Medicine and Surgery, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA
| | - Eneida Male
- Dept of Thoracic Medicine and Surgery, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA
| | - Eduardo C Dominguez
- Dept of Thoracic Medicine and Surgery, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA
| | - Amandeep Aneja
- Pathology and Laboratory Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA
| | - Zhao Huaqing
- Dept of Clinical Science, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA
| | - Chandra Dass
- Dept of Clinical Radiology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA
| | - Kartik Shenoy
- Dept of Thoracic Medicine and Surgery, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA
| | - Nathaniel Marchetti
- Dept of Thoracic Medicine and Surgery, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA
| | - Francis C Cordova
- Dept of Thoracic Medicine and Surgery, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA
| | - Gerard J Criner
- Dept of Thoracic Medicine and Surgery, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA
| | - A James Mamary
- Dept of Thoracic Medicine and Surgery, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA
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