rate of respiration vs respiratory rate

rate of respiration and respiratory rate both are nouns.

Word	Noun	Adjective	Verb	Adverb
rate of respiration	Yes	No	No	No
respiratory rate	Yes	No	No	No

As nouns, rate of respiration and respiratory rate are synonyms defined as:

rate of respiration and respiratory rate: the rate at which a person inhales and exhales; usually measured to obtain a quick evaluation of a person's health

rate of respiration (noun)	respiratory rate (noun)
the rate at which a person inhales and exhales; usually measured to obtain a quick evaluation of a person's health	the rate at which a person inhales and exhales; usually measured to obtain a quick evaluation of a person's health