Abstract
Introduction: Patients with SCI often have impaired cough function with mechanical insufflation-exsufflation (MIE) frequently used in clinical practice as part of airway secretion management. Optimal insufflation and exsufflation pressures have not been investigated in SCI patients although higher pressures are increasingly advocated.
Methods: MIE was delivered at low pressure (LP;+30cmH2O/-30cmH2O) and high pressure (HP;+60cmH2O/-60cmH2O) in a random order to patients already using home MIE for secretion clearance. Parasternal electromyography (EMGpara), to quantify neural respiratory drive (NRD), and electrical impedance tomography (EIT) were measured throughout.
Results: 8 SCI patients (aged 55±20y) were recruited. Resting self-ventilating tidal volume was 486±165mL and minute ventilation was 7.8±2.5L/min. All patients had inspiratory muscle weakness (sniff nasal inspiratory pressure 39±28cmH2O) and a weak cough (cough peak expiratory flow [cPEF] 158±103L/min). Baseline NRD was elevated (EMGpara 16.6±10.1uV; EMGpara%max 49±42%) but there was no change following MIE (p=0.35). cPEF was higher during HP-MIE (273±62L/min) compared with LP-MIE (229±57 L/min; p=0.012). The change in cPEF from baseline was also higher with HP-MIE (p=0.024). There was no difference in peak inspiratory-expiratory flow ratio (PIF-PEF) between LP (0.61)and HP-MIE (0.64). There were no significant changes in surface area of ventilation or global inhomogeneity as measured by EIT after MIE.
Conclusion: In stable SCI patients high pressure MIE promotes expiratory airflow without unloading the inspiratory muscles. Use of HP-MIE may be required to achieve adequate airway clearance.
Footnotes
Cite this article as: European Respiratory Journal 2019; 54: Suppl. 63, PA797.
This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).
- Copyright ©the authors 2019