Final answer:
Given an alveolar PCO₂ of 60 mmHg, the blood pH will likely be decreased, and with chronic compensation, the bicarbonate concentration would be increased. Option d (both a and c are true) is the correct answer, as a normal PO₂ would not necessarily cause abnormal oxygen saturation of hemoglobin. The correct option is d) both a and c are true
Step-by-step explanation:
The question asks whether the pH will be less than normal (a), the percent saturation of hemoglobin by oxygen will be less than normal (b), whether bicarbonate concentration will be greater than normal (c), or if both a and c or all of the above are true, given that alveolar PO₂ = 100 mmHg and PCO₂ = 60 mmHg.
The normal partial pressure of carbon dioxide (PCO₂) in the alveoli is about 40 mmHg, indicating that an alveolar PCO₂ of 60 mmHg is elevated. High PCO₂ levels can lead to respiratory acidosis, which would decrease the blood pH (decreased pH). In compensation for this acidotic state, the kidney would retain bicarbonate (HCO₃⁻), leading to an increased bicarbonate concentration. This aligns with option d (both a and c are true), assuming the condition is chronic enough for renal compensation to have taken place.
In terms of hemoglobin saturation with oxygen, this depends mostly on the PO₂, which is stated to be normal at 100 mmHg. A normal PO₂ would generally mean normal oxygen saturation of hemoglobin, barring factors such as abnormal hemoglobin, temperature, or pH changes, suggesting that the percent saturation by oxygen would not necessarily be less than normal only by the given PO₂ value. The correct option is d) both a and c are true