NCLEX-RNReduction of Risk PotentialMedium
A client with a history of COPD has the following arterial blood gas results: pH 7.28, PaCO2 60 mmHg, HCO3 24 mEq/L. The nurse interprets this finding as which acid-base imbalance?
- AMetabolic alkalosis, partially compensated
- BRespiratory acidosis, uncompensated
- CMetabolic acidosis, uncompensated
- DRespiratory alkalosis, compensated
Show answer & explanationAnswer & explanation
Correct answer: B. Respiratory acidosis, uncompensated
The pH (7.28) is acidic, PaCO2 (60) is elevated indicating a respiratory cause, and HCO3 (24) is normal, showing no metabolic compensation has occurred yet. This is uncompensated respiratory acidosis, consistent with CO2 retention seen in COPD.
Why the other options are wrong
- A. Metabolic alkalosis would show elevated pH and elevated HCO3.
- C. Metabolic acidosis would show low HCO3, not a normal value.
- D. Respiratory alkalosis would show an elevated pH, not a low one.
ABG Interpretation - Respiratory Acidosis
Acid-base imbalance from CO2 retention, causing decreased pH and elevated PaCO2.
- Normal pH: 7.35–7.45
- Normal PaCO2: 35–45 mmHg
- Normal HCO3: 22–26 mEq/L
- Uncompensated = only one value abnormal besides pH
Memory trick: ROME: Respiratory Opposite, Metabolic Equal (pH & CO2 move opposite in respiratory).