Final answer:
PACO2 indicates the pressure of carbon dioxide in arterial blood, with normal readings ranging from 35-45 mmHg, demonstrating efficient gas exchange in the lungs.
Step-by-step explanation:
The measure that indicates the pressure of carbon dioxide in arterial blood and shows how well the lungs are getting rid of carbon dioxide is called the PACO2. The normal reading for PACO2 levels in arterial blood is typically between 35-45 mmHg for males and 32-45 mmHg for females. Given these values, the blood efficiently releases carbon dioxide into the alveoli during gas exchange, maintaining the proper acid-base balance in the body.