Final answer:
In compensated respiratory alkalosis, laboratory changes typically include a decreased blood bicarbonate level as the kidneys compensate for a primary reduction in pCO2 by excreting more bicarbonate. This compensation, involving hydrogen ion conservation and bicarbonate excretion, helps maintain a nearly normal pH.
Step-by-step explanation:
The typical laboratory value changes associated with compensated respiratory alkalosis include a decreased blood bicarbonate (HCO3-) level. Initially, the bicarbonate concentration is normal when the condition arises due to a primary decrease in the partial pressure of carbon dioxide (pCO2). However, as the body attempts to compensate, the kidneys reduce bicarbonate production and increase its excretion to correct the blood pH. This renal compensation helps to reestablish the proper balance between bicarbonate and carbonic acid. If the compensation is successful, a near-normal pH is maintained despite the low pCO2.
In the case of respiratory alkalosis, the body's primary issue is a CO2 deficiency, which leads to an elevation in blood pH. When this occurs, the kidneys compensate by conserving hydrogen ions (H+) and excreting bicarbonate, seen as a decrease in serum bicarbonate. This process is slower than respiratory compensation and may take several hours to days. While this compensation helps to maintain pH within the physiological range, it's limited by factors such as the renal cells' potassium exchange capacity.