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To determine a reliable quantitative method of measuring diaphragmatic EMG (EMGdi), electrical activity of the diaphragm was obtained via an esophageal electrode during CO2 rebreathing in 6 normal males and processed three different ways: 1) integration (area), 2) as a moving time average, and 3) as a moving time variance. Integrated activity was quantified(More)
The effects of inspiratory flow resistance on mouth occlusion pressure (P0.15) and diaphragmatic EMG (EMGdi) responses to CO2 rebreathing were studied in normal subjects. Occlusion pressures were measured 150 msec after onset of an inspiratory effect; EMGdi was analyzed as a moving time average and quantified in terms of peak activity and rate of rise of(More)
To evaluate mouth occlusion pressure as an index of neural drive to the respiratory muscles that is independent of lung mechanics, the occlusion pressure response to rebreathing was studied in 7 normal subjects under control conditions and during flow-resistive loading. Inspiratory, expiratory, and combined inspiratory-expiratory flow resistances of 5 and(More)
The EMGdi response to both isocapnic hypoxia and hyperoxic hypercapnia was studied in the same sitting in six normal subjects. Rebreathing methods achieving "open loop" conditions were used. EMGdi was quantified as a moving time average. In almost all subjects, during hypoxia changes in EMGdi were inversely and hyperbolically related to changes in PAO2.(More)
We determined the relationship between mouth occlusion pressure and diaphragmatic electromyography during CO2 rebreathing with and without inspiratory flow resistance. Diaphragmatic electromyography was measured as a moving time average; occlusion pressures were measured 150 msec after onset of an inspiratory effort against a closed airway (P.15). P.15(More)
The effects of electrode position and gastric-balloon anchoring on esophageal diaphragmatic EMG (EMGdi) responses to CO2 rebreathing were studied in seven normal sitting humans using an esophageal catheter that consisted of four platinum wire coils enabling simultaneous recording of three EMGdi signals from three different sites in the esophagus. A gastric(More)
Changes in phrenic nerve activity, quantified as a moving time average, PNG(t), were characterized during complete airway occlusion at functional residual capacity (FRC) and compared to simultaneously occurring changes in intratracheal pressure. In anesthetized cats breathing room air and during CO2 breathing, PNG(t) during occlusion was the same as that(More)
In 7 normal subjects, mouth occlusion pressure was evaluated as an index of neural drive to the respiratory muscles during CO2 rebreathing, with and without the addition of 2 degrees of elastic loads. During control and loaded rebreathing, changes in both mouth occlusion pressure and ventilation were linearly related to changes in end-tidal PCO2. With(More)