Who created the term cold blue for hospitals?

When my son was in picu I asked bc the hospital we were in used code red. There are no standard definitions or conventions for the use of codes in hospitals I was told by the nurse. While code blue does refer to a cardiopulmonary arrest at many hospitals, it doesn't necessarily mean the same thing everywhere.

Your answer is  d.)relationship between pressure and air volume and led to the understanding of how respiration works