Final answer:
The effective use of Terbutaline is indicated by 'increased minute respiration' due to its main function as a bronchodilator. However, its non-selective beta-adrenergic activity may cause an increase in heart rates and thus should be used cautiously.
Step-by-step explanation:
Terbutaline is a medication that acts as a bronchodilator, primarily used to treat asthma and other respiratory conditions. Its main function is to relax and open airways to make breathing easier, it also has secondary effects due to its non-selective beta-adrenergic activity. Hence, it may cause increased heart rate due to its activity on the heart's beta-1 receptors.
In the choices given, it can be surmised that an effective indicator of Terbutaline's activity would be 'a. Increased minute respiration'. This is a sign that the bronchi are dilated, thus improving airflow and breathing. It's important to note, however, that excessive use of this medication may lead to rapid heart rates (Increased epinephrine and norepinephrine release) and should be used with caution in patients with heart disease.
Learn more about Terbutaline