Abstract
Introduction: HMV in COPD remains controversial. Current data indicates improvements in arterial carbon dioxide (PaCO2) are mediated by improved pulmonary mechanics and hypercapnic ventilatory response (HCVR). This hypothesis has yet to be tested in a controlled trial and no studies have investigated changes in neural respiratory drive (NRD) measured by parasternal EMG (EMGpara).
Method: Patients with persistent hypercapnia (PaCO2 >7 kPa) 2-4 weeks after resolution of an acute exacerbation of COPD were randomised to home oxygen therapy (HOT) or HOT and HMV. Baseline studies included HCVR and EMGpara. Patients were re-studied at 6 weeks.
Results: 20 patients have been recruited and randomised.
Follow up data is presented on 9 patients. Ventilator settings were IPAP 28±3, EPAP 5±1, RR 15±1. Significant improvement in both PaO2 and PaCO2 only occurred in the HMV group.
There was a significant between group difference in HCVR and NRD.
Conclusion: These preliminary data suggest that the addition of HMV to HOT in this group is associated with improvements in gas exchange and this appears in part mediated by changes in HCVR and NRD suggesting “resetting” of central drive.
- © 2011 ERS