Chest
Original Research: Heart FailureClosing Capacity and Gas Exchange in Chronic Heart Failure
Section snippets
Patients
The study was carried out in 20 stable ambulatory patients (18 men) with congestive heart failure due to cardiomyopathy (6 after ischemia) without pleural effusions. None had been hospitalized within 20 days preceding the study. None were current smokers, but nine patients were ex-smokers. All patients received therapy with diuretics (carvedilol, 15 patients; digitalis, 9 patients; oral anticoagulant therapy [dicumarol], 7 patients; and dobutamine IV, 1 patient). Within 1 month prior to
Results
Table 1 provides the anthropometric characteristics and baseline respiratory data for control subjects and CHF patients. In the control subjects, all baseline respiratory data were within normal limits; the MRC and Borg scores were zero, while the CHF patients exhibited slightly higher levels of MRC and Borg dyspnea scores.
In CHF patients, the FEV1/FVC ratio was within normal limits, while TLC and its subdivisions were reduced. This is also shown in Figure 1, where, for comparative purposes,
Discussion
The new findings of this study are that in CHF patients at rest (mostly in Weber class B and C), the following conditions prevail: (1) CC is not increased; (2) as a result of decreased FRC, however, airway closure with compromised pulmonary gas exchange is present during tidal breathing; (3) tidal FL is absent; (4) ventilation is increased as a result of increased fR with a concurrent decrease in Paco2; and (5) Pimax is decreased. Together with the concurrent increase in P0.1, this implies a
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