How do medical device brands distribute the products(such as blood pressure monitor) from headquarters to end consumers?

1.How do medical device brands distribute the products from headquarters to end consumers? How many resellers are there until reaching the end consumer? 2.What is the gross margin at each stage of the distribution, starting from the headquarters to the end consumer? 3. What's the distribution channel in the U.S.? Home medical device refer to the following device: blood pressure monitor, glucose meter, thermometer, oximeter, weighing scale, etc.