Which set of results indicates uncompensated respiratory alkalosis?

In the context of acid-base balance, uncompensated respiratory alkalosis is characterized by a primary increase in pH due to a decrease in carbon dioxide (PCO2) levels, indicating hyperventilation. The values of bicarbonate (HCO3) during uncompensated respiratory alkalosis often remain within the normal range and do not adjust to counterbalance the elevated pH.

In the correct option, the pH is 7.66, which is elevated, indicating alkalosis. The PCO2 level is 20 mm Hg, which is significantly low, aligning with hyperventilation. The HCO3 at 22 mmol/L is near the normal range, showing no compensatory metabolic alkalosis has occurred in response to the respiratory alkalosis. This profile indicates that the state is uncompensated because the bicarbonate level has not yet adapted to the changes in respiratory function.

The other options present different scenarios. For instance, one option shows elevated HCO3 levels in conjunction with a high pH and low PCO2, which suggests compensation could be occurring or a transient metabolic disturbance might be involved, rather than an uncompensated respiratory alkalosis. The key element determining uncompensated respiratory alkalosis is the lack of adjustment