Respiratory muscle unloading during auto-adaptive non-invasive ventilation

SummaryRationaleNon-invasive ventilation (NIV) has been shown to improve clinical outcomes in acute and chronic hypercapnic respiratory failure. A new timed, automated, auto-adaptive non-invasive ventilatory mode (TA-mode) has been recently introduced.ObjectiveTo investigate the degree of respiratory muscle unloading with this new mode in comparison to assisted (S-mode) NIV in healthy individuals.MethodsWork of breathing, pressure time product and transdiaphragmatic pressure time product were measured during unassisted breathing, assisted and TA-mode-NIV in eight healthy, awake volunteers at inspiratory pressures of 20 and expiratory pressures of 4 hPa.ResultsAssisted and TA-mode-NIV reduced the work of breathing by 50 and 89.1%, pressure time product by 61.5 and 72.6% and transdiaphragmatic pressure time product by 77 and 88.7%, respectively when compared to unassisted breathing. The degree of respiratory muscle unloading was higher during TA-mode-NIV when compared to assisted non-invasive ventilation (work of breathing p < 0.001, pressure time product p = 0.04 and transdiaphragmatic pressure time product p = 0,01).ConclusionTA-mode-NIV achieved significant higher levels of respiratory muscle unloading in healthy individuals when compared to assisted non-invasive ventilation.