Chest
Wedge Pressure Measurement in Obstructive Pulmonary Disease
Section snippets
MATERIALS AND METHODS
The 19 patients studied had been admitted to the Jefferson Davis Hospital intensive care unit because of acute exacerbations of chronic obstructive pulmonary disease with respiratory failure. All patients fulfilled the American Thoracic Society criteria5 for obstructive pulmonary disease and had airways obstruction on pulmonary function testing with the percent of forced vital capacity expired within the first second (FEV1 percent) of 20 percent to 60 percent. Their ages were from 42 to 77
RESULTS
Respiratory fluctuation in wedge pressure tracings could be minimized and in some cases eliminated by electrical subtraction of the esophageal pressure (Fig 1). The magnitude of the total change in esophageal pressure and the total change in wedge pressure correlated well (Fig 2). The intrathoracic pressure changes of groups 1 and 2 are shown in Table 1. Four patients were able to produce marked intrathoracic pressure changes by voluntary hyperventilation, and despite great fluctuations of the
DISCUSSION
In patients with severe obstructive pulmonary disease intrathoracic pressure can influence the recording of intracardiac and wedge pressures. Experimentally, pulmonary artery and vein pressures have been shown to parallel changes in intrathoracic pressure when there are positive pressures and within limits negative pressures.8 If marked, we feel these intrathoracic changes may result in elevated mean wedge values relative to atmosphere. Since the pressures in the heart and pulmonary veins are
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The opinions expressed herein are those of the authors and cannot be construed as reflecting the views of the Navy Department or of the Naval Service at large.
Manuscript received March 8; revision accepted May 10.