Question

What is the change in bicarbonate for acute/chronic respiratory acidosis?

1) Increase
2) Decrease
3) No change
4) Cannot be determined

Answer 1

In respiratory acidosis, the bicarbonate level increases as a compensatory mechanism to counteract the excess CO2 in the blood. Chronic respiratory acidosis typically involves a more pronounced increase in bicarbonate as the kidneys adjust over time to restore the acid-base balance.

Step-by-step explanation:

The change in bicarbonate (HCO3−) for acute or chronic respiratory acidosis is an increase. In the case of respiratory acidosis, there is an excess of CO2 in the blood, leading to a decrease in blood pH. The body attempts to compensate for this by increasing renal production and retention of bicarbonate, which helps neutralize the excess acidity.

This compensatory mechanism leads to a higher bicarbonate level as the kidneys try to restore the proper ratio of bicarbonate to carbonic acid (the product of CO2 in solution) to maintain acid-base balance. In acute cases, compensation may not be fully established, but in chronic respiratory acidosis, compensation by increased bicarbonate levels is typical.

For example, in the case of the 64-year-old with asthma, the lab results show a compensated respiratory acidosis, evidenced by the increased total HCO3−. The pathophysiology of asthma, which involves obstructed airways, leads to an accumulation of CO2, reduced pH, and subsequently, a respiratory acid-base imbalance.