Which symptom should a nurse anticipate in a patient with asthma who is not responding to bronchodilator therapy?

In a patient with asthma who is not responding to bronchodilator therapy, tachycardia is a key symptom to anticipate. Asthma exacerbations lead to airway obstruction and impaired gas exchange, causing hypoxemia and hypercapnia. The body compensates for decreased oxygen levels by increasing the heart rate to maintain adequate oxygen delivery to vital organs. This compensatory response results in tachycardia as the sympathetic nervous system is activated, aimed at enhancing perfusion.

In contrast, symptoms such as bradycardia, hypotension, or increased appetite do not typically occur in this scenario. Bradycardia would indicate a decreased heart rate, which is not consistent with the body's response to hypoxia. Hypotension could occur if the exacerbation is severe enough to cause shock, but in general, it is not a direct response to an asthma exacerbation. Increased appetite is also unlikely during an acute asthma episode due to the physical stress and discomfort associated with difficulty breathing, which often leads to a decreased desire to eat. Thus, tachycardia stands out as a common compensatory mechanism in this context.