NORCERT 8 Mains-2025
Medical & Surgical Nursing
Hard
A patient's ABG values are: pH 7.30, pCO2 50 mmHg, and HCO3 24 mEq/L. What is the most likely acid-base imbalance?
Appeared in: NORCERT 8 Mains-2025
Explanation
- The patient's pH of 7.30 is below the normal range of 7.35-7.45, which signifies an acidotic state.
- The pCO2 level of 50 mmHg is above the normal range of 35-45 mmHg. Elevated pCO2 (hypercapnia) results from CO2 retention and causes the blood to become more acidic.
- The primary cause is identified as respiratory because the direction of the pCO2 (acidic) matches the direction of the pH (acidotic).
- The HCO3 level of 24 mEq/L is within the normal range of 22-26 mEq/L, indicating that the kidneys have not yet begun to compensate for the imbalance.
Why Other Options Were Wrong
- Option B: Metabolic acidosis is incorrect because it would present with a low pH and a low bicarbonate (HCO3) level, typically below 22 mEq/L. This patient's HCO3 is normal.
- Option C: Respiratory alkalosis is incorrect because it is characterized by a high pH (above 7.45) and a low pCO2 (below 35 mmHg) due to hyperventilation. This patient's values are the opposite.
- Option D: Metabolic alkalosis is incorrect as it involves a high pH and a high HCO3 level (above 26 mEq/L). This patient has a low pH and a normal HCO3.
Related Visual
- Visual 1: Flowchart - A step-by-step decision tree for ABG interpretation, starting with pH, then assessing pCO2 and HCO3 to determine the primary disorder and compensation.
- Visual 2: Chart - The ROME (Respiratory Opposite, Metabolic Equal) mnemonic chart, which helps quickly associate the direction of pH with pCO2 and HCO3.
- Visual 3: Diagram - An illustration showing the lungs and kidneys as the primary organs for regulating acid-base balance, highlighting their roles in respiratory and metabolic compensation.
Clinical Relevance
- Nursing practice connection: Knowing Interpretation of Arterial Blood Gas (ABG) values to identify acid-base imbalances helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
- Identifying respiratory acidosis is a critical nursing skill, as it indicates inadequate ventilation (hypoventilation) which can lead to respiratory failure if not managed promptly.
- Common causes include COPD, pneumonia, opioid overdose (respiratory depression), and airway obstruction. Nursing interventions are aimed at improving ventilation and ensuring a patent airway.
- Nurses must administer oxygen cautiously to patients with chronic CO2 retention (like in COPD), as high-flow oxygen can diminish their respiratory drive. The target SpO2 is often lower (88-92%).
How to Approach the Question
- Step 1: Analyze the pH. Determine if it is acidotic (less than 7.35), alkalotic (greater than 7.45), or within the normal range.
- Step 2: Analyze the pCO2 (the respiratory component). A high pCO2 is acidic, and a low pCO2 is alkaline. Determine if the pCO2 value explains the pH imbalance.
- Step 3: Analyze the HCO3 (the metabolic component). A low HCO3 is acidic, and a high HCO3 is alkaline. Determine if the HCO3 value explains the pH imbalance.
- Step 4: Identify the primary disorder by matching the respiratory (pCO2) or metabolic (HCO3) component with the pH imbalance.
- Step 5: Assess for compensation. If the system not causing the problem is moving in the opposite direction to correct the pH, compensation is occurring. If it is still in the normal range, the condition is uncompensated.
Concept Tested & Keywords
- Concept Tested: Interpretation of Arterial Blood Gas (ABG) values to identify acid-base imbalances.
- Stem keywords: ABG values, pH 7.30, pCO2 50 mmHg, HCO3 24 mEq/L
- Lead-in keywords: most likely
- Clinical cues: pH below normal range indicates acidosis.
- Clinical cues: pCO2 above normal range indicates a respiratory cause for acidosis.
Question ID
QcsuRQWYSlQSJ6jqpSzuyV
Practise the full NORCERT 8 Mains-2025
Attempt every question from this paper in a timed mock, then review the full solution for each one.
More Fluid and Electrolytes: Balance and Distribution Questions
- All are crystalloid solution; except:
- ECG of the patient is showing ST depression, Prominent U wave and inverted T wave. Which of the electrolyte imbalance present?
- A patient reports calcium loss. What is the nursing intervention?
- The principle of hemodialysis in which the water is moving under high pressure to an area of lower pressure is:
- Measurement of arterial blood gas shows pH: 7.2, PaCO2 : 70 mm Hg, HCO3: 27 mmol/L and PaO2: 59 mm Hg. Interpret this:
- Fluid volume deficit or hypovolemia describes the loss of
- A patient presents to the emergency department with a serum pH of 7.25, pCO2 of 40 mmHg, HCO3 of 22 mEq/L, sodium of 150 mEq/L, and chloride of 100 m…
- A 65-year-old patient is admitted to the hospital with a serum sodium level of 132 mmol/L. Despite being asymptomatic at admission, the patient begin…
- You are assessing a patient who is experiencing hyperventilation, resulting in a below-normal carbon dioxide (CO2) level. The patient is exhibiting s…
- A patient undergoes nasogastric suctioning for several days. Which electrolyte imbalance is most likely to occur due to this treatment?
More NORCERT 8 Mains-2025 Questions
- A patient admitted in the ICU is receiving feeding through a Ryles tube. The nursing officer is about to give the next feed, which is scheduled for e…
- What clinical condition is shown in the image below?
- What is the most significant diagnostic test that needs to be done prior to a lumbar puncture?
- Identify the device shown in the image.
- The nurse is monitoring a child with burns during treatment. Which assessment provides the most accurate guide to determine the adequacy of fluid res…
- Which of the following assessment techniques should be avoided in a child with Wilms' tumor?
- In a conscious and stable patient, what instructions should be given while removing the central venous catheter to minimize complications?
- A nurse is caring for a schizophrenia patient who is experiencing auditory hallucinations. Which intervention is MOST appropriate?
- A belief that persists despite evidence to the contrary is characteristic of what?
- A schizophrenic patient with renal failure is admitted to the psychiatric ward for dialysis. When the time for the procedure arrives, the patient ref…