A son brings his father into the clinic, stating that his father's color has changed to bluish around the mouth. The father is confused, with a respiratory rate of 28 breaths per minute and scattered crackles throughout. The son states this condition just occurred within the last hour. Which of the following factors indicates that the client's condition has lasted for more than 1 hour?
a. Son's statement
b. Crackles
c. Respiratory rate
d. Cyanosis
