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- Broche, Ludovic, et al.
(author)
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Dynamic Mechanical Interactions Between Neighboring Airspaces Determine Cyclic Opening and Closure in Injured Lung
- 2017
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In: Critical Care Medicine. - 0090-3493 .- 1530-0293. ; 45:4, s. 687-694
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Journal article (peer-reviewed)abstract
- Objectives: Positive pressure ventilation exposes the lung to mechanical stresses that can exacerbate injury. The exact mechanism of this pathologic process remains elusive. The goal of this study was to describe recruitment/derecruitment at acinar length scales over short-time frames and test the hypothesis that mechanical interdependence between neighboring lung units determines the spatial and temporal distributions of recruitment/derecruitment, using a computational model. Design: Experimental animal study. Setting: International synchrotron radiation laboratory. Subjects: Four anesthetized rabbits, ventilated in pressure controlled mode. Interventions: The lung was consecutively imaged at - 1.5-minute intervals using phase-contrast synchrotron imaging, at positive end expiratory pressures of 12, 9, 6, 3, and 0 cm H2O before and after lavage and mechanical ventilation induced injury. The extent and spatial distribution of recruitment/derecruitment was analyzed by subtracting subsequent images. In a realistic lung structure, we implemented a mechanistic model in which each unit has individual pressures and speeds of opening and closing. Derecruited and recruited lung fractions (F-derecruaed, F-recruited) were computed based on the comparison of the aerated volumes at successive time points. Measurements and Main Results: Alternative recruitment/derecruitment occurred in neighboring alveoli over short-time scales in all tested positive end-expiratory pressure levels and despite stable pressure controlled mode. The computational model reproduced this behavior only when parenchymal interdependence between neighboring acini was accounted for. Simulations closely mimicked the experimental magnitude of F-derecruited and F-recruited when mechanical interdependence was included, while its exclusion gave F-recruited values of zero at positive end -expiratory pressure greater than or equal to 3 cm H2O. Conclusions: These findings give further insight into the microscopic behavior of the injured lung and provide a means of testing protective-ventilation strategies to prevent recruitment/derecruitment and subsequent lung damage.
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- Collins, Pamela Y, et al.
(author)
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RISING SUN : Prioritized Outcomes for Suicide Prevention in the Arctic
- 2019
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In: Psychiatric Services. - : American Psychiatric Association. - 1075-2730 .- 1557-9700. ; 70:2, s. 152-155
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Journal article (peer-reviewed)abstract
- The Arctic Council, a collaborative forum among governments and Arctic communities, has highlighted the problem of suicide and potential solutions. The mental health initiative during the United States chairmanship, Reducing the Incidence of Suicide in Indigenous Groups: Strengths United Through Networks (RISING SUN), used a Delphi methodology complemented by face-to-face stakeholder discussions to identify outcomes to evaluate suicide prevention interventions. RISING SUN underscored that multilevel suicide prevention initiatives require mobilizing resources and enacting policies that promote the capacity for wellness, for example, by reducing adverse childhood experiences, increasing social equity, and mitigating the effects of colonization and poverty.
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