Flow-controlled ventilation (FCV) improves regional ventilation in obese patients - a randomized controlled crossover
Jonas Weber1, Leonie Straka2, Silke Borgmann2
1Department of Anesthesiology and Critical Care, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany. jonas.weber@uniklinik-freiburg.de.
Background:
In obese patients, high closing capacity and low functional residual capacity increase the risk for expiratory alveolar collapse. Constant expiratory flow, as provided by the new flow-controlled ventilation (FCV) mode, was shown to improve lung recruitment. We hypothesized that lung aeration and respiratory mechanics improve in obese patients during FCV.
Methods:
We compared FCV and volume-controlled (VCV) ventilation in 23 obese patients in a randomized crossover setting. Starting with baseline measurements, ventilation settings were kept identical except for the ventilation mode related differences (VCV: inspiration to expiration ratio 1:2 with passive expiration, FCV: inspiration to expiration ratio 1:1 with active, linearized expiration). Primary endpoint of the study was the change of end-expiratory lung volume compared to baseline ventilation. Secondary endpoints were the change of mean lung volume, respiratory mechanics and hemodynamic variables.
Results:
The loss of end-expiratory lung volume and mean lung volume compared to baseline was lower during FCV compared to VCV (end-expiratory lung volume: FCV, - 126 ± 207 ml; VCV, - 316 ± 254 ml; p < 0.001, mean lung volume: FCV, - 108.2 ± 198.6 ml; VCV, - 315.8 ± 252.1 ml; p < 0.001) and at comparable plateau pressure (baseline, 19.6 ± 3.7; VCV, 20.2 ± 3.4; FCV, 20.2 ± 3.8 cmH2O; p = 0.441), mean tracheal pressure was higher (baseline, 13.1 ± 1.1; VCV, 12.9 ± 1.2; FCV, 14.8 ± 2.2 cmH2O; p < 0.001). All other respiratory and hemodynamic variables were comparable between the ventilation modes.
Conclusions:
This study demonstrates that, compared to VCV, FCV improves regional ventilation distribution of the lung at comparable PEEP, tidal volume, PPlat and ventilation frequency. The increase in end-expiratory lung volume during FCV was probably caused by the increased mean tracheal pressure which can be attributed to the linearized expiratory pressure decline.
Trial Registration:
German Clinical Trials Register: DRKS00014925. Registered 12 July 2018.
More Related Videos
08:35Oxygenation-sensitive Cardiac MRI with Vasoactive Breathing Maneuvers for the Non-invasive Assessment of Coronary Microvascular Dysfunction
Published on: August 17, 2022
05:56Author Spotlight: Enhancing Diagnostic Strategies and Biomarker Development for Comprehensive Lung Function Analysis
Published on: August 9, 2024
Related Concept Videos
01:23Mechanical Ventilation III: Noninvasive Ventilation
Noninvasive Positive-Pressure Ventilation...
01:27Chronic Obstructive Pulmonary Disease-IV: Assessement and Diagnostic Studies
Medical History
01:26COPD: Management Using Bronchodilators and Corticosteroids
01:23Physiological Control of Respiration
Breathing, a seemingly passive process, is regulated by the respiratory center in the brainstem. This center coordinates the involuntary control of respirations, which means it occurs without conscious effort, ensuring a smooth and uninterrupted pattern.
Regulation of Ventilation
The body maintains ventilation by monitoring levels of carbon dioxide (CO2), oxygen (O2), and hydrogen ion concentration (pH) in the arterial blood. Among these factors, the level of CO2 plays a crucial...
01:23Mechanical Ventilation II: Invasive Ventilation
Negative-Pressure Ventilators
Negative-pressure ventilators create a vacuum around the chest or body to draw air into the lungs, simulating breathing. This method does not require an...
01:19Factors Affecting Pulmonary Ventilation
Alveolar Surface Tension
The alveolar fluid lines the luminal surface of the alveoli and exerts a force called surface tension. This force is caused by the polar water molecules in the liquid being more strongly attracted to each...