Final answer:
Respiratory alkalosis is characterized by a pH greater than 7.45 and a PCO2 less than 35 mm Hg, often caused by hyperventilation which leads to a CO2 deficiency in the bloodstream.
Step-by-step explanation:
Respiratory alkalosis is characterized by a pH greater than 7.45 and a PCO2 less than 35 mm Hg. This condition arises when there is a decrease in the concentration of carbon dioxide in the bloodstream due to hyperventilation, leading to an increase in blood pH.
Disorders such as lung diseases, severe anxiety, or even an aspirin overdose can trigger this state. To identify this condition, laboratory tests measure the blood pH, PCO2, and HCO3- levels, which can reveal an imbalance and indicate if compensatory mechanisms are at play.
Of the options provided, the correct one is 'a. pH greater than 7.45 and PCO2 less than 35 mm Hg' as it corresponds with the definition and characteristics of respiratory alkalosis. During this state, the kidneys may try to compensate by reducing blood bicarbonate levels, aiming to normalize pH levels.