Your patient is a 15-year-old asthmatic who has been having difficulty breathing for 45 minutes but does not have his Xopenex inhaler with him. Capnography shows an ETCO2 of 45 mmHg. The best way to interpret this finding is:

A) this is a normal ETCO2, indicating that this is a mild asthma attack.
B) the patient's ETCO2 first dropped as he began to hyperventilate but now is rising again and may continue to rise to dangerous levels.
C) this is a high ETCO2, and the patient requires immediate ventilatory assistance to prevent respiratory arrest.
D) this is a low ETCO2 indicating that the patient is hyperventilating and thus in the early stages of an asthma attack.

B