What is the preferred agent for a chemical stress test in a patient with COPD?

In patients with chronic obstructive pulmonary disease (COPD), the preferred agent for a chemical stress test is dobutamine. This is due to its specific pharmacological profile. Dobutamine primarily increases heart rate and contractility, stimulating beta-1 adrenergic receptors, which is beneficial for patients who may have compromised pulmonary function.

Unlike agents such as adenosine, regadenoson, and dipyridamole, which cause vasodilation through different mechanisms (such as adenosine receptor activation), dobutamine does not lead to significant bronchoconstriction, making it safer and more suitable for patients with pre-existing pulmonary conditions like COPD. This is critical because patients with COPD already face difficulties with airflow, and additional bronchoconstriction would exacerbate their condition.

In summary, dobutamine is preferred for chemical stress testing in a COPD patient because it effectively increases cardiac output without exacerbating pulmonary issues, making it a safer option compared to the other agents.