The nurse in the ED monitors Joshua's peak expiratory flow rate (PEFR; maximal expiratory flow in 1 second). Joshua's personal best is 180 L/second. On initial presentation, Joshua was unable to initiate a blast into the peak flow meter. After the 3rd treatment with albuterol, he is able to blow 85 L/second.
Which is a correct interpretation of Joshua's current PEFR reading?
a. Since Joshua can initiate a blast, he is significantly improving.
b. Joshua is in the green zone, and routine control treatment can be resumed.
c. Joshua is in the yellow zone. Maintenance treatment needs to be increased.
d. Joshua is in the red zone. There is severe airway narrowing.