We hypothesized that considerable force reserve exists for the diaphragm muscle (DIAm) to
generate transdiaphragmatic pressures (Pdi) necessary to sustain ventilation. In rats, we
measured Pdi and DIAm EMG activity during different ventilatory (eupnea and hypoxia (10%
O2)–hypercapnia (5% CO2)) and non-ventilatory (airway occlusion and sneezing induced
by intranasal capsaicin) behaviors. Compared to maximum Pdi (Pdimax generated by
bilateral phrenic nerve stimulation), the Pdi generated during eupnea (21±2%) and hypoxia …