Patients with elevations in PVP, such as in congestive heart failure or mitral stenosis, have airflow limitation due to increased airways resistance. On physical examination, this may be manifested as wheezing. Although blood vessel engorgement and edema are thought to be responsible for this process, smooth muscle constriction may also be involved. Bronchial hyperresponsiveness to methacholine and acetylcholine has been demonstrated in cardiac asthma. Obviously, it is important to distinguish wheezing due to heart failure from wheezing due to intrinsic airway disease, as the treatment is substantially different. A careful history and physical examination, followed by a therapeutic trial of diuretics or bronchodilators, will answer the question.
Besides wheezing, patients with congestive heart failure often have coarse crackles. What other pulmonary diseases can cause crackles?
Chronic obstructive pulmonary disease (COPD, especially chronic bronchitis)
Interstitial lung disease.
As with cardiac asthma, a careful history is the best initial approach to diagnosis. Sophisticated analysis of crackles in different disease states has shown that cardiac crackles are typically more coarse and prolonged than the fine, late-inspiratory, short-duration crackles of interstitial lung disease. COPD crackles also tend to be of short duration, but are early in inspiration and are relatively infrequent and scant. Differentiating crackles of congestive heart failure from those of pneumonia and bronchiectasis is more difficult.
What new respiratory care modality can be used to treat cardiogenic pulmonary edema and congestive heart failure?
Continuous positive airway pressure (CPAP). CPAP is applied via a tight-fitting mask over the mouth and nose or nose alone. It is usually used to treat respiratory insufficiency due to obstructive sleep apnea or severe COPD. However, CPAP has also been shown to be effective in improving symptoms of acute pulmonary edema and may buy time when one is trying to avoid intubation while waiting for pharmacologic therapy to take effect.