A patient undergoes nasogastric suctioning for several days. Which electrolyte imbalance is most likely to occur due to this treatment?

Appeared in: NORCET 6 Prelims -2024

Explanation

Nasogastric (NG) suction removes gastric fluid, which is rich in potassium ions (K+).
Prolonged suctioning over several days leads to a significant net loss of potassium from the body, causing serum potassium levels to fall, a condition known as hypokalemia.
The loss of hydrochloric acid (H+ and Cl-) during NG suction also causes metabolic alkalosis.
Metabolic alkalosis further worsens hypokalemia by causing a shift of potassium from the extracellular fluid into the cells and by increasing the renal excretion of potassium.

Option A: Hyperkalemia is high potassium. NG suction removes potassium from the body, leading to a deficit (hypokalemia), not an excess.
Option B: Hypernatremia is high sodium. While dehydration from fluid loss can occur, leading to a relative increase in sodium concentration, the direct loss of potassium-rich gastric fluid makes hypokalemia a more direct and certain consequence.
Option D: Hypercalcemia is high calcium. Gastric suction does not directly impact the hormones (PTH, calcitonin) or systems that regulate calcium balance.

Clinical Relevance

Nursing practice connection: Use the key finding related to Electrolyte imbalances resulting from nasogastric suctioning to guide bedside assessment, documentation, and the next nursing action.
Nurses caring for patients with NG suction must diligently monitor serum electrolyte levels, particularly potassium, through regular lab tests.
It is crucial to assess the patient for clinical signs of hypokalemia, which include muscle weakness, fatigue, constipation, and potentially life-threatening cardiac arrhythmias.
Potassium replacement, often administered intravenously, may be required based on lab results and the patient's clinical condition.

How to Approach the Question

First, identify the core clinical intervention in the question: 'nasogastric suctioning for several days'.
Next, recall the physiological composition of the fluid being removed. Gastric fluid is acidic (containing HCl) and rich in potassium (K+).
Predict the consequences of prolonged removal of this specific fluid. The loss of K+ will lead to hypokalemia. The loss of H+ will lead to metabolic alkalosis.
Finally, evaluate the given options against your prediction. 'Hypokalemia' directly matches the predicted outcome of potassium loss.
Eliminate the other options by considering their causes. Hyperkalemia, hypernatremia, and hypercalcemia are caused by different pathophysiological processes not directly related to the removal of gastric acid.

Concept Tested & Keywords

Concept Tested: Electrolyte imbalances resulting from nasogastric suctioning.
Stem keywords: nasogastric suctioning, several days, electrolyte imbalance
Lead-in keywords: most likely
Clinical cues: The duration of 'several days' is a key cue, as it indicates a prolonged loss of gastric fluid, making significant electrolyte depletion highly probable.

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E6 Nelson Textbook of Pediatrics(2024) — Volume 1 p. 564-566

E6 Nursing Brunner Adult Health 3SA Vol 1 Part 1 p. 157-159

Practise the full NORCET 6 Prelims -2024

Attempt every question from this paper in a timed mock, then review the full solution for each one.