Which channel(s) are you treating when working on the posterior torso?

A 69-year-old female was involved in a motor vehicle crash. She is semiconscious with a blood pressure of 80/50 mm Hg and a heart rate of 74 beats/min that is weak. Her daughter, who was uninjured in the crash, tells you that her mother has a history of hypertension and takes beta-blockers. Considering the fact that this patient is probably in shock, what is the MOST likely explanation for the absence of tachycardia?

A. deterioration of the cardiac conduction system B. intrathoracic bleeding and cardiac compression C. the effects of her antihypertensive medication D. failure of the parasympathetic nervous system

A ____________________ is a group of three-digit categories in the ICD-9-CM manual that represent a single disease or a group of closely related conditions.

Fill in the blank(s) with the appropriate word(s).