Patho Patho #11

Question

Interpret the following: pH 7.22, PaCO2 58, HCO3 23.

Answers

  1. Metabolic acidosis.
    • Rationale:

      This answer choice is not correct because metabolic acidosis will reveal a low pH and a decreased HCO3.

  2. Metabolic alkalosis.
    • Rationale:

      This answer choice is not correct because metabolic alkalosis will reveal a low pH and and elevated HCO3.

  3. Respiratory acidosis.
    • Rationale:

      This answer is correct because respiratory acidosis will reveal a low pH and an elevated PaCO2.

  4. Respiratory alkalosis.
    • Rationale:

      This answer choice is not correct because respiratory alkalosis will reveal an elevated pH and a decreased PaCO2.

Overview

There are 4 categories of acid-base imbalances. In order to accurately interpret ABG’s it is essential to learn normal values of pH, PaCO1, and HCO3. Respiratory acidosis will display a low pH with an elevated PaCO2.

Explanation

Learning Outcomes

Respiratory acidosis is a common acid-base imbalance in clients with chronic respiratory disorders such as COPD. To accurately interpret ABGs, first look at the pH to determine if it is elevated or decreased. The next step to ABG interpretation is to evaluate PaCO2 vs HCO3 and determine which value is more out of it’s normal range. With respiratory acidosis, pH will be low, and PaCO2 will be very high.

Test Taking Tip

When interpreting ABGs the first step is to determine whether the pH is decreased or elevated and then compare PaCO2 vs. HCO3. If PaCO2 is more out of its normal range then the origin of the imbalance is respiratory; if HCO3 is more out of its normal range then the origin of the imbalance is metabolic.

Video Rationale