You are called to the scene of a patient complaining of difficulty breathing. You arrive to find a 62-year-old
male sitting forward in a chair and obviously anxious. Upon assessment, respiratory rate is 36 shallow and
labored. The patient’s heart rate is 120 weak and irregular. You also note his skin is slightly cyanotic centrally
and significantly cyanotic peripherally. From the following, select the most critical assessment you should
perform on this patient.

A: Assess lung sounds bilaterally.
B: Check the patient's glucose level.
C: Obtain the pulse oximetry reading.
D: Perform a quick-look with the paddles or pads.