NORCET-7 Mains-2024: A patient arterial blood gases (ABG) analysis report shows pH 7.48, CO2 32 mm hg, HCO3 22. What is the possib…

NORCET-7 Mains-2024

Medical & Surgical Nursing

Hard

Appeared in: NORCET-7 Mains-2024

Explanation

The patient's pH of 7.48 is elevated (normal: 7.35-7.45), indicating a state of alkalosis.
The PaCO2 of 32 mmHg is low (normal: 35-45 mmHg). Since CO2 is an acid, a low level causes alkalosis.
Using the ROME mnemonic (Respiratory Opposite, Metabolic Equal), the pH is high and the PaCO2 is low, moving in opposite directions, which points to a respiratory cause.
The HCO3− level of 22 mEq/L is within the normal range (22-26 mEq/L), indicating that the metabolic system has not yet compensated for the imbalance.
Therefore, the combination of high pH and low PaCO2 confirms respiratory alkalosis.

Option A: Respiratory acidosis is characterized by a low pH (less than 7.35) and a high PaCO2 (greater than 45 mmHg) due to hypoventilation. The patient's values are the opposite.
Option B: Metabolic acidosis is characterized by a low pH (less than 7.35) and a low HCO3− (less than 22 mEq/L). The patient has a high pH and normal HCO3−.
Option C: Metabolic alkalosis is characterized by a high pH (greater than 7.45) and a high HCO3− (greater than 26 mEq/L). While the patient's pH is high, their HCO3− is normal, and the primary driver is the low PaCO2.

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.
Accurate ABG interpretation is a critical skill for nurses to assess a patient's oxygenation and acid-base status, guiding timely interventions.
Respiratory alkalosis is most commonly caused by hyperventilation due to anxiety, pain, fever, or conditions like pulmonary embolism. Nurses must identify and address the underlying cause.
Nursing interventions for respiratory alkalosis focus on correcting the cause of hyperventilation. This may include providing reassurance to an anxious patient, managing pain, or encouraging slow, regular breathing.

How to Approach the Question

First, analyze the pH. A value above 7.45 indicates alkalosis, and a value below 7.35 indicates acidosis.
Second, examine the PaCO2 (the respiratory component). A value outside the 35-45 mmHg range suggests a respiratory problem.
Third, examine the HCO3− (the metabolic component). A value outside the 22-26 mEq/L range suggests a metabolic problem.
Use the ROME mnemonic to determine the primary cause: If pH and PaCO2 are moving in Opposite directions, it's a Respiratory issue. If pH and HCO3− are moving in an Equal direction, it's a Metabolic issue.
Finally, assess for compensation. If the component that is NOT the primary cause is out of its normal range in the opposite direction of the pH, compensation is occurring. If it is still normal, the condition is uncompensated.

Concept Tested & Keywords

Qd_e5twYgH7NjZCT-fBJdD

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

E6 Nursing Fundamentals Taylor p. 785-787

E6 Textbook of Biochemistry for medical StudentsDM Vasudevan Part 2 — Subpart A (pp 1-239 of 478) p. 82-84