NCLEX-RNPhysiological AdaptationHard
A client with a history of chronic obstructive pulmonary disease (COPD) has the following arterial blood gas results: pH 7.34, PaCO2 58 mmHg, HCO3- 32 mEq/L. Which interpretation is correct?
- APartially compensated respiratory acidosis
- BUncompensated respiratory acidosis
- CMetabolic alkalosis with respiratory compensation
- DFully compensated respiratory acidosis
Show answer & explanationAnswer & explanation
Correct answer: A. Partially compensated respiratory acidosis
The pH (7.34) is low-normal but still acidotic, PaCO2 is elevated (respiratory acidosis primary problem), and HCO3- is elevated as a compensatory metabolic response; because the pH has not returned fully to normal (7.35-7.45), this represents partial compensation.
Why the other options are wrong
- B. Uncompensated would show normal HCO3-, but here HCO3- is elevated, indicating compensation is occurring.
- C. The primary disorder is respiratory (elevated PaCO2), not metabolic.
- D. Full compensation would show a normal pH (7.35-7.45); pH 7.34 is still slightly acidotic.
ABG Compensation Interpretation
Compensation is classified as none, partial, or full based on whether pH has returned to normal range despite abnormal PaCO2/HCO3-.
- Normal pH range: 7.35-7.45
- Partial compensation: pH abnormal, but opposite system shifted toward normal
- Full compensation: pH normalized, both PaCO2 and HCO3- abnormal
- Uncompensated: only one value abnormal, pH markedly abnormal
Memory trick: ROME: Respiratory Opposite, Metabolic Equal