Letter A is a(n) ________, which branches off the tertiary bronchi. 

The recommended dose of Lanoxin is 0.25-1.0 mg IV. At doses in excess of 1.5 mg, Lanoxin becomes toxic. A drug's margin of safety—the range between an effective dose and a lethal dose—is known as the:

A) physiologic dosing regimen. B) drug toxicity level. C) therapeutic index. D) none of the above.

What are the criteria to define hypopnea?

a. 20% decrease in airflow and 4% oxygen desaturation b. 20% decrease in airflow and 2% oxygen desaturation c. 30% decrease in airflow and 4% oxygen desaturation d. 30% decrease in airflow and 2% oxygen desaturation