Changes in neural respiratory drive during initiation of domicilary non-invasive ventilation (NIV)

Introduction: Neural respiratory drive, measured by surface parasternal electromyogram (sEMGpara), reflects the respiratory muscle load-capacity balance. We hypothesised that sEMGpara would quantify the unloading of the respiratory chest wall muscles during the initiation of NIV. Method: sEMGpara was recorded from the second intercostal space. The peak root mean square signal per breath was averaged over 2 minutes and normalised to a maximal inspiratory manoeuvre (sEMGpara%max). We measured sEMGpara%max during wakefulness, self ventilation overnight and the first night of NIV set up. NIV was titrated using oximetry and capnography. 2 minute epochs of breathing were analysed every 10 minutes. Results:28 patients (16 male) participated; 10 chronic obstructive pulmonary disease (COPD), 11 obesity hypoventilation syndrome (OHS) and 7 neuromuscular disease (NMD). Inter-occasion reliability of sEMGpara%max was assessed a day apart in 10 patients with an agreement of 0.93. NMD patients had the highest levels of sEMG%max during wakefulness. sEMGpara%max fell overnight in all groups, with a significant further reduction during the first night of NIV in the obese group. ![Figure][1] Conclusion:Respiratory muscle unloading may not be optimised during the first night of NIV in all patients. The use of automated techniques to monitor sEMGpara%max, may guide ventilator settings to improve respiratory muscle unloading during NIV set up. [1]: pending:yes