A nurse interprets arterial blood gas results as indicative of which condition: HCO3 18mEq, PaCO2 28 mmHg, pH 7.30?

The arterial blood gas results suggest a state of metabolic acidosis. The key indicators to consider are the low bicarbonate (HCO3) level, which is 18 mEq, and the low pH of 7.30. In a healthy system, the normal range for bicarbonate is typically between 22 to 26 mEq/L, so anything below this threshold points toward a metabolic disturbance.

In metabolic acidosis, the bicarbonate level decreases as the body loses bicarbonate or accumulates acid, leading to a decrease in blood pH, thus making it more acidic. The low pH of 7.30 confirms acidosis since normal arterial blood pH ranges from 7.35 to 7.45.

Additionally, the low partial pressure of carbon dioxide (PaCO2) at 28 mmHg suggests that there is hyperventilation occurring as a compensatory mechanism, where the lungs attempt to blow off CO2 in response to the metabolic acidosis. This compensation helps to mitigate the acidosis by increasing pH slightly, although the primary issue of low bicarbonate still indicates a metabolic origin.

This combination of low HCO3, low pH, and low PaCO2 aligns with metabolic acidosis