Dataset Information

Pathophysiological profile of non-ventilated lung injury in healthy female pigs undergoing mechanical ventilation.

ABSTRACT:

Background

Lung regions excluded from mechanical insufflation are traditionally assumed to be spared from ventilation-associated lung injury. However, preliminary data showed activation of potential mechanisms of injury within these non-ventilated regions (e.g., hypoperfusion, inflammation).

Methods

In the present study, we hypothesized that non-ventilated lung injury (NVLI) may develop within 24 h of unilateral mechanical ventilation in previously healthy pigs, and we performed extended pathophysiological measures to profile NVLI. We included two experimental groups undergoing exclusion of the left lung from the ventilation with two different tidal volumes (15 vs 7.5 ml/kg) and a control group on bilateral ventilation. Pathophysiological alteration including lung collapse, changes in lung perfusion, lung stress and inflammation were measured. Lung injury was quantified by histological score.

Results

Histological injury score of the non-ventilated lung is significantly higher than normally expanded lung from control animals. The histological score showed lower intermediate values (but still higher than controls) when the tidal volume distending the ventilated lung was reduced by 50%. Main pathophysiological alterations associated with NVLI were: extensive lung collapse; very low pulmonary perfusion; high inspiratory airways pressure; and higher concentrations of acute-phase inflammatory cytokines IL-6, IL-1β and TNF-α and of Angiopoietin-2 (a marker of endothelial activation) in the broncho-alveolar lavage. Only the last two alterations were mitigated by reducing tidal volume, potentially explaining partial protection.

Conclusions

Non-ventilated lung injury develops within 24 h of controlled mechanical ventilation due to multiple pathophysiological alterations, which are only partially prevented by low tidal volume.

SUBMITTER: Spinelli E

PROVIDER: S-EPMC10869686 | biostudies-literature | 2024 Feb

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Pathophysiological profile of non-ventilated lung injury in healthy female pigs undergoing mechanical ventilation.

Spinelli Elena E Damia Anna A Damarco Francesco F Gregori Beatrice B Occhipinti Federica F Busani Zara Z Leali Marco M Battistin Michele M Lonati Caterina C Zhao Zhanqi Z Storaci Alessandra Maria AM Lopez Gianluca G Vaira Valentina V Ferrero Stefano S Rosso Lorenzo L Gatti Stefano S Mauri Tommaso T

Communications medicine 20240215 1

<h4>Background</h4>Lung regions excluded from mechanical insufflation are traditionally assumed to be spared from ventilation-associated lung injury. However, preliminary data showed activation of potential mechanisms of injury within these non-ventilated regions (e.g., hypoperfusion, inflammation).<h4>Methods</h4>In the present study, we hypothesized that non-ventilated lung injury (NVLI) may develop within 24 h of unilateral mechanical ventilation in previously healthy pigs, and we performed e ...[more]

PMID: 38361130

Similar Datasets

Project description:ObjectivesDetermine the intra-tidal regional gas and blood volume distributions at different levels of atelectasis in experimental lung injury. Test the hypotheses that pulmonary aeration and blood volume matching is reduced during inspiration in the setting of minimal tidal recruitment/derecruitment and that this mismatching is an important determinant of hypoxemia.DesignPreclinical study.SettingResearch laboratory.SubjectsSeven anesthetized pigs 28.7 kg (SD, 2.1 kg).InterventionsAll animals received a saline-lavage surfactant depletion lung injury model. Positive end-expiratory pressure was varied between 0 and 20 cm H2O to induce different levels of atelectasis.Measurements and main resultsDynamic dual-energy CT images of a juxtadiaphragmatic slice were obtained, gas and blood volume fractions within three gravitational regions calculated and normalized to lung tissue mass (normalized gas volume and normalized blood volume, respectively). Ventilatory conditions were grouped based upon the fractional atelectatic mass in expiration (< 20%, 20-40%, and ≥ 40%). Tidal recruitment/derecruitment with fractional atelectatic mass in expiration greater than or equal to 40% was less than 7% of lung mass. In this group, inspiration-related increase in normalized gas volume was greater in the nondependent (818 µL/g [95% CI, 729-908 µL/g]) than the dependent region (149 µL/g [120-178 µL/g]). Normalized blood volume decreased in inspiration in the nondependent region (29 µL/g [12-46 µL/g]) and increased in the dependent region (39 µL/g [30-48 µL/g]). Inspiration-related changes in normalized gas volume and normalized blood volume were negatively correlated in fractional atelectatic mass in expiration greater than or equal to 40% and 20-40% groups (r = 0.56 and 0.40), but not in fractional atelectatic mass in expiration less than 20% group (r = 0.01). Both the increase in normalized blood volume in the dependent region and fractional atelectatic mass in expiration negatively correlated with PaO2/FIO2 ratio (ρ = -0.77 and -0.93, respectively).ConclusionsIn experimental atelectasis with minimal tidal recruitment/derecruitment, mechanical inspiratory breaths redistributed blood volume away from well-ventilated areas, worsening PaO2/FIO2.

Project description:IntroductionMechanical ventilation (MV) of mice is increasingly required in experimental studies, but the conditions that allow stable ventilation of mice over several hours have not yet been fully defined. In addition, most previous studies documented vital parameters and lung mechanics only incompletely. The aim of the present study was to establish experimental conditions that keep these parameters within their physiological range over a period of 6 h. For this purpose, we also examined the effects of frequent short recruitment manoeuvres (RM) in healthy mice.MethodsMice were ventilated at low tidal volume V(T) = 8 mL/kg or high tidal volume V(T) = 16 mL/kg and a positive end-expiratory pressure (PEEP) of 2 or 6 cm H(2)O. RM were performed every 5 min, 60 min or not at all. Lung mechanics were followed by the forced oscillation technique. Blood pressure (BP), electrocardiogram (ECG), heart frequency (HF), oxygen saturation and body temperature were monitored. Blood gases, neutrophil-recruitment, microvascular permeability and pro-inflammatory cytokines in bronchoalveolar lavage (BAL) and blood serum as well as histopathology of the lung were examined.ResultsMV with repetitive RM every 5 min resulted in stable respiratory mechanics. Ventilation without RM worsened lung mechanics due to alveolar collapse, leading to impaired gas exchange. HF and BP were affected by anaesthesia, but not by ventilation. Microvascular permeability was highest in atelectatic lungs, whereas neutrophil-recruitment and structural changes were strongest in lungs ventilated with high tidal volume. The cytokines IL-6 and KC, but neither TNF nor IP-10, were elevated in the BAL and serum of all ventilated mice and were reduced by recurrent RM. Lung mechanics, oxygenation and pulmonary inflammation were improved by increased PEEP.ConclusionsRecurrent RM maintain lung mechanics in their physiological range during low tidal volume ventilation of healthy mice by preventing atelectasis and reduce the development of pulmonary inflammation.

Dataset Information

Pathophysiological profile of non-ventilated lung injury in healthy female pigs undergoing mechanical ventilation.

Background

Methods

Results

Conclusions

Publications

Pathophysiological profile of non-ventilated lung injury in healthy female pigs undergoing mechanical ventilation.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets