The Nurse receives an ABG Report that stated pH 7.35 , PCO2 62 mmHg, HCO3 28 mEq/L, Which of the following interpretation she will record?

Appeared in: AIIMS Raipur NO - 2017 (Shift-1)

Explanation

The primary disorder is identified by comparing the pH to the PCO₂ and HCO₃ values.
The pH of 7.35 is at the lowest end of the normal range (7.35-7.45), indicating an underlying acidosis.
The PCO₂ of 62 mmHg is high (normal: 35-45 mmHg), pointing to respiratory acidosis as the primary problem.
The HCO₃ of 28 mEq/L is also high (normal: 22-26 mEq/L), which signifies a compensatory action by the kidneys to retain bicarbonate and neutralize the acid.
Since the pH has returned to the normal range, the condition is considered fully compensated.

Option A: This is incorrect because the primary problem is respiratory, not metabolic. In metabolic acidosis, the primary change would be a low HCO₃.
Option B: This is incorrect. The pH indicates acidosis, not alkalosis. In metabolic alkalosis, both the pH and HCO₃ would be high initially.
Option D: This is incorrect because the patient's values indicate acidosis (high PCO₂), not alkalosis (which would be a low PCO₂).

Visual 1: Flowchart: A step-by-step flowchart for ABG interpretation, starting with pH, then assessing PCO₂ and HCO₃ to determine the primary disorder and level of compensation.
Visual 2: Diagram: A ROME (Respiratory Opposite, Metabolic Equal) mnemonic diagram to help visualize the relationship between pH, PCO₂, and HCO₃ in different acid-base disorders.

Clinical Relevance

Nursing practice connection: Knowing Arterial Blood Gas (ABG) Interpretation helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Compensated respiratory acidosis is often seen in patients with chronic respiratory diseases, such as Chronic Obstructive Pulmonary Disease (COPD). Their bodies have had time to adapt to chronically high CO₂ levels.
A nurse observing these ABG results in a patient with known COPD would recognize this as their baseline or chronic state, but would still monitor for any signs of acute decompensation (e.g., worsening shortness of breath, altered mental status).
What if the patient's pH was 7.25? If the pH was 7.25 with the same PCO₂ and HCO₃, it would be classified as partially compensated respiratory acidosis, indicating an acute worsening of their condition that the body has not yet fully corrected.

How to Approach the Question

First, look at the pH. Determine if it is acidotic (<7.35), normal (7.35-7.45), or alkalotic (>7.45). Note which end of the normal range it falls on.
Next, examine the PCO₂ (the respiratory parameter). A high PCO₂ (>45 mmHg) indicates respiratory acidosis. A low PCO₂ (<35 mmHg) indicates respiratory alkalosis.
Then, examine the HCO₃ (the metabolic parameter). A low HCO₃ (<22 mEq/L) indicates metabolic acidosis. A high HCO₃ (>26 mEq/L) indicates metabolic alkalosis.
Determine the primary disorder by matching the pH with either the PCO₂ or HCO₃. If the pH is acidotic, which other value is also acidotic (high PCO₂ or low HCO₃)?
Finally, assess for compensation. If the pH is normal, but PCO₂ and HCO₃ are abnormal, it is fully compensated. If all three values are abnormal, it is partially compensated.

Concept Tested & Keywords

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