Benefit of Physiologically Variable Over Pressure-Controlled Ventilation in a Model of Chronic Obstructive Pulmonary Disease: A Randomized Study

• Published in: Frontiers in physiology Vol. 11; p. 625777
• Main Authors: Dos Santos Rocha, Andre, Südy, Roberta, Bizzotto, Davide, Kassai, Miklos, Carvalho, Tania, Dellacà, Raffaele L, Peták, Ferenc, Habre, Walid
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Media S.A 13.01.2021
• Subjects: animal model; COPD; gas exchange; lung mechanics; Physiology; variable ventilation; variable ventilation; animal model; gas exchange; lung mechanics; COPD
• ISSN: 1664-042X; 1664-042X
• DOI: 10.3389/fphys.2020.625777

The advantages of physiologically variable ventilation (PVV) based on a spontaneous breathing pattern have been demonstrated in several respiratory conditions. However, its potential benefits in chronic obstructive pulmonary disease (COPD) have not yet been characterized. We used an experimental model of COPD to compare respiratory function outcomes after 6 h of PVV versus conventional pressure-controlled ventilation (PCV). Rabbits received nebulized elastase and lipopolysaccharide throughout 4 weeks. After 30 days, animals were anesthetized, tracheotomized, and randomized to receive 6 h of physiologically variable ( = 8) or conventional PCV ( = 7). Blood gases, respiratory mechanics, and chest fluoroscopy were assessed hourly. After 6 h of ventilation, animals receiving variable ventilation demonstrated significantly higher oxygenation index (PaO /FiO 441 ± 37 (mean ± standard deviation) 354 ± 61 mmHg, < 0.001) and lower respiratory elastance (359 ± 36 463 ± 81 cmH O/L, < 0.01) than animals receiving PCV. Animals ventilated with the variable mode also presented less lung derecruitment (decrease in lung aerated area, -3.4 ± 9.9 -17.9 ± 6.7%, < 0.01) and intrapulmonary shunt fraction (9.6 ± 4.1 17.0 ± 5.8%, < 0.01). PVV applied to a model of COPD improved oxygenation, respiratory mechanics, lung aeration, and intrapulmonary shunt fraction compared to conventional ventilation. A reduction in alveolar derecruitment and lung tissue stress leading to better aeration and gas exchange may explain the benefits of PVV.