Effects of time-controlled adaptive ventilation on cardiorespiratory parameters and inflammatory response in experimental emphysema

• Published in: Journal of applied physiology (1985) 2022-02, Vol.132 (2), p.564-574
• Main Authors: Oliveira, Milena Vasconcellos de, Magalhães, Raquel Ferreira de, Rocha, Nazareth de Novaes, Fernandes, Marcus Vinicius, Antunes, Mariana Alves, Morales, Marcelo Marcos, Capelozzi, Vera Luiza, Satalin, Joshua, Andrews, Penny, Habashi, Nader M, Nieman, Gary, Rocco, Patricia Rieken Macedo, Silva, Pedro Leme
• Format: Article
• Language: English
• Subjects: Animals; Emphysema - metabolism; Humans; Lung - metabolism; Positive-Pressure Respiration - methods; Pulmonary Emphysema - metabolism; Rats; Respiration, Artificial - methods; Ventilator-Induced Lung Injury - metabolism
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/japplphysiol.00689.2021

The time-controlled adaptive ventilation (TCAV) method attenuates lung damage in acute respiratory distress syndrome. However, so far, no study has evaluated the impact of the TCAV method on ventilator-induced lung injury (VILI) and cardiac function in emphysema. We hypothesized that the use of the TCAV method to achieve an expiratory flow termination/expiratory peak flow (E /E ) of 25% could reduce VILI and improve right ventricular function in elastase-induced lung emphysema in rats. Five weeks after the last intratracheal instillation of elastase, animals were anesthetized and mechanically ventilated for 1 h using TCAV adjusted to either E /E 25% or E /E 75%, the latter often applied in acute respiratory distress syndrome (ARDS). Pressure-controlled ventilation (PCV) groups with positive end-expiratory pressure levels similar to positive end-release pressure in TCAV with E /E 25% and E /E 75% were also analyzed. Echocardiography and lung ultrasonography were monitored. Lung morphometry, alveolar heterogeneity, and biological markers related to inflammation [interleukin 6 (IL-6), CINC-1], alveolar pulmonary stretch (amphiregulin), lung matrix damage [metalloproteinase 9 (MMP-9)] were assessed. E /E 25% reduced respiratory system peak pressure, mean linear intercept, B lines at lung ultrasonography, and increased pulmonary acceleration time/pulmonary ejection time ratio compared with E /E 75%. The volume fraction of mononuclear cells, neutrophils, and expression of IL-6, CINC-1, amphiregulin, and MMP-9 were lower with E /E 25% than with E /E 75%. In conclusion, TCAV with E /E 25%, compared with E /E 75%, led to less lung inflammation, hyperinflation, and pulmonary arterial hypertension, which may be a promising strategy for patients with emphysema. The TCAV method reduces lung damage in ARDS. However, so far, no study has evaluated the impact of the TCAV method on ventilator-induced lung injury and cardiac function in experimental emphysema. The TCAV method at E /E ratio of 25%, compared with E /E of 75% (frequently used in ARDS), reduced lung inflammation, alveolar heterogeneity and hyperinflation, and pulmonary arterial hypertension in elastase-induced emphysema. TCAV may be a promising and personalized ventilation strategy for patients with emphysema.