Chest
Clinical Investigations in Critical CareVentilatory Muscle Support in Respiratory Failure with Nasal Positive Pressure Ventilation
Section snippets
Subjects
The study population consisted of three normal subjects, four subjects with neuromuscular disorders with or without associated chest wall deformities (restrictive group), and five subjects with severe COPD (obstructive group). Subject characteristics are shown in Table 1.
In the restrictive group, two subjects (nos. 5,7) were receiving nocturnal intermittent positive pressure ventilation and one (no. 6) was on intermittent positive pressure ventilation continuously, all through fenestrated
RESULTS
One subject (no. 12) with COPD was extremely anxious and unable to synchronize his breathing with the ventilator. There were no evident clinical characteristics which distinguished him from others in the obstructive group (Table 1). This subject was not included in further analysis. The other 11 subjects tolerated NPPV well without discomfort or complications.
Figure 1 is a representative tracing from a subject with COPD (no. 10). During spontaneous breathing (Fig 1A), large negative deflections
DISCUSSION
The results of this study demonstrate that NPPV can achieve, in the short term, two major goals of assisted ventilation, namely: to provide adequate ventilation while simultaneously allowing for a significant reduction in spontaneous inspiratory effort. Other investigators have shown that long-term intermittent NPPV can result in sustained improvements in Pco2 and clinical status, as well as increased exercise tolerance in patients with chronic respiratory failure.9,10,12, 13, 14 However, the
ACKNOWLEDGMENTS
The writers thank Dr. J. Martin for thoughtful review of the manuscript, and Drs. P. Goldberg and M. Angle for referring patients.
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Supported by the Quebec Thoracic Society and the Environmental Lung Disease Research Fund.
Manuscript received March 2; revision accepted June 1, 1989.