Fig. 7.

Negative airway pressure generation (Paw) (following airway occlusion), inspired volume, end-tidal Pco₂, oxygen saturation (SaO₂), mean blood pressure (BP), and heart rate (HR) are plotted every 30 min during continuous inspiratory muscle pacing with HF-SCS. Results are means ± SE (n = 3). Airway pressure and inspired volume generation remained constant throughout the initial 5.5 h of stimulation. End-tidal Pco₂ and oxygen saturation were also maintained between 35 and 40 mmHg and 95 and 99%, respectively. Mean blood pressure and heart rate also remained stable throughout this period. After 5.5 h of continuous pacing, stimulus parameters were increased, resulting in an increase in inspired volume and consequent fall in Pco₂, which was sustained over a 30-min period.