Tag: neuromuscular

The fact that PPV is able to substantially reduce diaphragmatic work in both awake and sleeping subjects suggests that this may be the preferred method of AV to be used in future studies. Other questions that must be examined include the effect of PPV during both non-REM and REM sleep, and patient acceptance of and […]

In our study, we used only very short exposures (15 minutes) to ventilatory support. It could be argued that with further training and practice, our subjects would have achieved further reductions in diaphragmatic activity with NPV. However, the time and effort required to produce significant diaphragm capture and rest with NPV should be compared with […]

The reduction in iEMG during NPV in our study is comparable to that achieved by other investigators. Some investigators have found larger increases, but we agree with the conclusions of Ro-denstein and coworkers who stated that the reduced EMG during NPV is most likely the result of practice with the negative pressure ventilators. In the […]

We attempted to match Ve during assisted ventilation to the level during QB. However, an additional goal was to maximize subject comfort during the AV The small differences in Ve and etC02 during PPV as compared with NPV were not significant. Although reduction in diaphragm EMG can be achieved with hyperventilation by mechanical means, we […]

We have shown that PPV is more effective than NPV in achieving an acute reduction of diaphragmatic activity in the naive awake subject. We interpret the reduction in integrated EMG during PPV to represent a decrease in neural drive. The decrease in peak Pdi and PTI of the diaphragm is consistent with reduced diaphragmatic energy […]

The other measures of diaphragmatic activity also demonstrated greater reduction during PPV. Figure 3 and Table 1 illustrate the reduction in the PTI, peak Pdi, and CV-Vt. The reduction of PTI during NPV was different from QB (58 percent, p = 0.05) and the reduction during PPV was different from both QB (29 percent, p […]

Figures 2 and 3 summarize the effect of PPV and NPV in both normals and patients while receiving AV To maintain patient comfort, the Vt and Ve were higher during PPV as compared with QB and NPV (p = 0.01 or p = 0.05). Consequently, the etC02 was significantly lower during PPV (p = 0.01). […]

We investigated two groups of subjects. The first group consisted of five men with normal pulmonary function. The second group was composed of six male patients with COPD, ex-cigarette smokers (48 ±28 pack years, mean ± SD), and average age of 71 ±5 years (range, 63 to 77 years). The study day FEV, was 1.13 […]

Positive pressure ventilation in the control mode was delivered through a nasal CPAP mask via a volume cycled ventilator (Lifecare, Portable Lifecare PLV 100, Lafayette, CO). Between each ventilator session, the subjects resumed QB for 10 to 15 minutes to allow the breathing pattern to return to baseline conditions. The order of assisted ventilation was […]

The integration continued until an expiratory volume was detected. This integration had no “leak” associated with it since the period of integration was certain, and there was no need for integrating over the entire EMG record, as is the case with the analog integrators. From this standpoint, our method of integrating the EMG is an […]