If a CHO/nurse is caring for a patient with an Ileostomy, which Acid Base imbalance is most likely to occur?

Appeared in: Uttarakhand CHO - 2021

Explanation

An ileostomy involves the diversion of the ileum (the final section of the small intestine) to an opening in the abdominal wall, bypassing the colon.
Fluid in the small intestine is rich in bicarbonate (HCO₃⁻), an alkaline substance.
A high-output ileostomy leads to significant loss of this bicarbonate-rich fluid.
The loss of a base (bicarbonate) from the body results in a relative excess of acid, leading to metabolic acidosis.

Option A: Respiratory acidosis is caused by alveolar hypoventilation, leading to the retention of carbon dioxide (CO₂). It is a primary respiratory problem, not a consequence of gastrointestinal fluid loss.
Option B: Respiratory alkalosis is caused by alveolar hyperventilation, leading to excessive elimination of CO₂. This is related to breathing patterns, not intestinal fluid loss.
Option D: Metabolic alkalosis is caused by the loss of acid, typically from the upper GI tract. An ileostomy involves loss of fluid from the lower GI tract, which is alkaline.

Clinical Relevance

Nursing practice connection: Use the key finding related to Acid-base imbalance associated with ileostomy to guide bedside assessment, documentation, and the next nursing action.
Nurses must diligently monitor stoma output volume and consistency to anticipate and identify metabolic acidosis early in patients with an ileostomy.
Early recognition allows for timely fluid and electrolyte replacement, preventing severe complications like dehydration, cardiac arrhythmias (often linked to concurrent potassium loss), and altered mental status.
What if? If the patient had a pyloric obstruction causing severe vomiting instead of an ileostomy, the most likely imbalance would be metabolic alkalosis due to the loss of stomach acid (HCl).

How to Approach the Question

First, identify the key condition in the question: a patient with an ileostomy.
Recall the location of the ileostomy in the gastrointestinal (GI) tract, which is at the end of the small intestine.
Remember the composition of the fluid lost from the lower GI tract. Intestinal fluid is alkaline because it is rich in bicarbonate (HCO₃⁻).
Connect the condition (ileostomy) to its physiological consequence (loss of large amounts of bicarbonate-rich fluid).
Apply the principles of acid-base balance: losing a base (HCO₃⁻) leads to a state of acidosis.
Determine the origin of the imbalance. Since it's due to the loss of bicarbonate (a metabolic component), it is metabolic acidosis.

Concept Tested & Keywords

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E6 Nursing Fundamentals Potter Perry 12e Part 5 pp. 57-59, 56-58

Practise the full Uttarakhand CHO - 2021

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