Question: Taking Blood Pressure Manually?

Hey guys,

So I am enrolled in a certified nursing assistant program and last time we started doing blood pressure measurements manually. I am really confused on a certain aspect of the procedure; the diastolic pressure measurement.

My instructor told me this:

The first sound you hear is Systolic pressure ( I get this)
Then she said that diastolic pressure is the last "distinct" sound you hear before it murmurs then goes silent. This I do not get. I always thought that diastolic pressure was recorded when you don't hear any more sounds. I have read this in a lot of other articles also.

Example of the confusion

My instructor had a stethocope that had two ear pieces so we could each hear. I got 120/78 and she got 118/110. How does that happen? Isn't 110 kind of a high for an average sized healthy guy? so confused....