11/4/2023 0 Comments Increased dead space ventilation![]() ![]() This is therefore termed anatomical dead space as it serves no respiratory function. These findings would support the concept of pulmonary vasculopathy leading to altered ventilation perfusion matching (increased dead space) and resultant dyspnea, independent of markers of cardiac function.Įxercise heart failure lung perfusion ventilation.Anatomic dead space is an important phenomenon in respiratory physiology whereby, owing to the fact that upper airways do not function as locations for gas exchange, and because of the tidal nature of ventilation, there is always a fraction of the inspired air that does not perform a physiologic function of exchanging carbon dioxide for oxygen. Low resting pulmonary diffusing capacity in heart failure is indicative of high dead space ventilation during exercise, leading to excessive and inefficient ventilation. Dead space at maximal exercise also correlated inversely with peak oxygen consumption (r = -0.598, P < 0.001), peak oxygen consumption per kilogram (r = -0.474, P < 0.001), and 6-minute-walk distance (r = -0.317, P = 0.021) in the heart failure group but not in control subjects. ![]() Pulmonary diffusing capacity at rest was a significant predictor of dead space ventilation at maximal exercise (r = -0.524, P < 0.001) in heart failure but not in control subjects. Dead space ventilation was calculated using the Bohr equation. ![]() We analyzed detailed cardiac and pulmonary data at rest and during maximal incremental cardiopulmonary exercise testing from 87 consecutive heart transplant assessment patients and 18 healthy control subjects. To determine the relationship between pulmonary diffusing capacity at rest and dead space ventilation during exercise, and to examine the influence of dead space ventilation on exercise in heart failure. ![]() We hypothesized that the reduced pulmonary diffusing capacity in patients with heart failure would predict greater dead space ventilation during exercise and that this would lead to impairment in exercise capacity. Reduced pulmonary diffusing capacity at rest and excessively high ventilation during exercise are common in heart failure. Patients with chronic heart failure have limited exercise capacity, which cannot be completely explained by markers of cardiac dysfunction. ![]()
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