In patients with COPD, which factor becomes the body's major stimulus to breathing?

In patients with Chronic Obstructive Pulmonary Disease (COPD), the body's major stimulus to breathe shifts from the typical regulation by carbon dioxide levels to becoming more influenced by lower oxygen levels. This change occurs because, in healthy individuals, elevated carbon dioxide is the primary driver of the respiratory drive. However, in patients with COPD, prolonged exposure to high carbon dioxide levels can lead to a condition where their respiratory system becomes less sensitive to it.

As the disease progresses, these patients may develop a reliance on oxygen levels in their blood to stimulate breathing. When oxygen levels drop (hypoxemia), this stimulates the respiratory drive to increase ventilation. Therefore, in this context, lower oxygen levels become the crucial factor prompting breathing efforts. This physiological adaptation is particularly important for healthcare professionals to understand when managing patients with COPD, especially when applying supplemental oxygen, as it can suppress their natural drive to breathe if given inappropriately.