The client is admitted with chronic obstructive pulmonary disease. Blood gases reveal pH 7.36, CO2 45, O2 84, bicarb 28. The nurse would assess the client to be in?

1. A

   Uncompensated acidosis

2. B

   Compensated alkalosis

3. C

   Compensated respiratory acidosis

4. D

   Uncompensated metabolic acidosis

Appeared in: DHS 2018 shift 1st

Explanation

• The pH of 7.36 is within the normal range (7.35-7.45), which indicates that the body's compensatory mechanisms have successfully returned the pH to a non-life-threatening level (full compensation).
• Because the pH is on the lower side of the normal midpoint of 7.40, the primary underlying problem is an acidosis.
• The PaCO2 of 45 mm Hg is at the high end of the normal range (35-45 mm Hg). In a COPD patient, this points to CO2 retention, which is the source of the respiratory acidosis.
• The bicarbonate (HCO3) level of 28 mEq/L is elevated (normal: 22-26 mEq/L). This demonstrates that the kidneys are retaining bicarbonate (a base) to buffer the excess respiratory acid, confirming metabolic compensation.

Why Other Options Were Wrong

• Option A: This is incorrect because the pH is within the normal range. In an uncompensated state, the pH would be abnormal (less than 7.35) and the compensatory component (HCO3) would be normal.
• Option B: This is incorrect because the patient's pH of 7.36 indicates an underlying acidosis, not alkalosis. A compensated alkalosis would have a pH in the normal range but on the alkaline side (greater than 7.40).
• Option D: This is incorrect because the primary problem is respiratory, not metabolic. Also, the condition is compensated, not uncompensated. Uncompensated metabolic acidosis involves a low pH and a low HCO3.

Related Visual

Clinical Relevance

• Nursing practice connection: Knowing Arterial Blood Gas (ABG) interpretation for a patient with Chronic Obstructive Pulmonary Disease (COPD) helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
• Monitoring ABGs is a critical nursing responsibility for patients with COPD to evaluate the effectiveness of gas exchange and guide interventions like oxygen therapy and respiratory treatments.
• Nurses must be cautious when administering oxygen to COPD patients with chronic CO2 retention. High concentrations of oxygen can diminish their hypoxic drive to breathe, potentially leading to increased CO2 levels (hypercapnia) and CO2 narcosis.
• What if the patient's pH was 7.32 with the same PaCO2 and HCO3? The condition would be classified as 'partially compensated respiratory acidosis.' The body is attempting to compensate (high HCO3), but it has not yet been successful in returning the pH to the normal range, indicating a more acute or worsening condition that requires urgent intervention.

How to Approach the Question

• First, analyze the pH to determine if the blood is acidotic (less than 7.35), alkalotic (greater than 7.45), or within the normal range (7.35-7.45). If normal, determine if it leans towards acidosis (less than 7.40) or alkalosis (greater than 7.40) to find the primary problem.
• Second, examine the PaCO2 (normal: 35-45 mm Hg). This is the respiratory parameter. Use the ROME mnemonic: Respiratory Opposite (pH and PaCO2 move in opposite directions). A high PaCO2 with low pH indicates respiratory acidosis.
• Third, examine the HCO3 (normal: 22-26 mEq/L). This is the metabolic parameter. Use the ROME mnemonic: Metabolic Equal (pH and HCO3 move in the same direction). A high HCO3 with high pH indicates metabolic alkalosis.
• Finally, determine compensation. If the pH is normal, compensation is full. If the pH is abnormal but the opposing system is trying to correct it (e.g., high PaCO2 and high HCO3), compensation is partial. If the opposing system is normal, it is uncompensated.
• In this scenario: pH is normal (acid side), PaCO2 is high-normal, and HCO3 is high. This combination indicates the body has fully compensated for a primary respiratory acidosis.

Concept Tested & Keywords

• Concept Tested: Arterial Blood Gas (ABG) interpretation for a patient with Chronic Obstructive Pulmonary Disease (COPD).
• Stem keywords: chronic obstructive pulmonary disease, COPD, blood gases, pH 7.36, CO2 45, bicarb 28
• Lead-in keywords: assess the client to be in
• Clinical cues: Patient has COPD, a condition known to cause CO2 retention.
• Clinical cues: pH is within normal range, suggesting compensation.

Question ID

QynNrIaWNdUviNnSXtIRYH

Copy ID

Reference Book

E6 Nursing Fundamentals Potter Perry 12e Part 5 p. 56-58

E6 Nursing Fundamentals Taylor p. 785-787