p Does the Efficacy of High Intensity Ventilation in Stable COPD Depend on the Ventilator Model? A Bench-to-Bedside Study

Purpose: The European Task Force for chronic non-invasive ventilation in stable COPD recommends the use of high pressure-support (PS) level to maximize the decrease in PaCO2. It is possible that the ventilator model can influence the need for higher or lower pressure levels. Research Question: To determine the differences between ventilators in a bench model with an increased inspiratory demand; and to compare the degree of muscular unloading measured by parasternal electromyogram (EMGpara) provided by the different ventilators in real patients with stable COPD. Patients and Methods: Bench: four levels of increasing progressive effort were pro-grammed. The response of nine ventilators to four levels of PS and EPAP of 5 cm H2O was studied. The pressure-time product was determined at 300 and 500 msec (PTP 300/500). Clinical Study: The ventilators were divided into two groups, based on the result of the bench test. Severe COPD patients with non-invasive ventilation (NIV) were studied, ran-domly comparing the performance of one ventilator from each group. Muscle unloading was measured by the decrease in EMGpara from its baseline value. Results: There were significant differences in PTP 300 and PTP 500 in the bench study. Based on these results, home ventilators were classified into two groups; group 1 included four models with higher PTP 300. Ten COPD patients were recruited for the clinical study. Group 1 ventilators showed greater muscle unloading at the same PS than group 2. Conclusion: The scale of pressure support in NIV for high intensity ventilation may be influenced by the ventilator model. Clinical Trials.gov: NCT03373175.