Excessive vomiting will cause: ? - NORCET 6 mains-2024

NORCET 6 mains-2024

Applied Physiology

Medium

Appeared in: NORCET 6 mains-2024

Explanation

Excessive vomiting causes the loss of gastric contents, which are rich in hydrochloric acid (HCl).
The loss of hydrogen ions (H+) from the body leads to an increase in the concentration of bicarbonate in the extracellular fluid.
This increase in bicarbonate relative to carbonic acid raises the blood pH above the normal range (7.35-7.45).
This specific type of acid-base imbalance is known as metabolic alkalosis.
It is often accompanied by hypochloremia (low chloride) and hypokalemia (low potassium) due to fluid and electrolyte losses.

Option A: Acidosis is a condition of increased acidity in the blood (low pH). Vomiting causes a loss of acid, not a gain or retention of it.
Option C: This option is incorrect because excessive vomiting has a well-defined and predictable effect on the body's acid-base balance.
Option D: This option is incorrect because acidosis and alkalosis are opposite conditions. A patient cannot have both simultaneously from the same cause.

Visual 1: Diagram: Pathophysiology of Metabolic Alkalosis - A flowchart showing how loss of HCl from vomiting leads to increased serum bicarbonate, elevated pH, and compensatory responses by the lungs and kidneys.
Visual 2: Infographic: Signs and Symptoms of Metabolic Alkalosis - A visual summary of clinical manifestations like confusion, tetany, arrhythmias, and compensatory hypoventilation.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Acid-base imbalance caused by excessive vomiting as background academic context rather than a clinical decision trigger.
Nurses must be able to recognize patients at risk for metabolic alkalosis, especially those with persistent vomiting, nasogastric suction, or on certain diuretics.
Key nursing assessments include monitoring intake and output, checking for signs of volume depletion (tachycardia, hypotension), and observing for neurological changes or muscle cramping (tetany) which can result from associated electrolyte shifts.
Promptly administering antiemetic medications as prescribed is a critical nursing intervention to stop the underlying cause and prevent worsening of the alkalosis.

How to Approach the Question

First, identify the core process in the question: 'excessive vomiting'.
Recall the contents of the stomach. The stomach contains gastric acid, which is primarily hydrochloric acid (HCl).
Analyze the effect of losing this substance. Vomiting removes acid (H+ ions) from the body.
Relate this loss to acid-base balance. A loss of acid makes the body's fluids more basic, or alkaline.
Select the term that describes a state of increased alkalinity: 'Alkalosis'.
Differentiate from 'Acidosis', which would be caused by a gain of acid or loss of base (like bicarbonate in diarrhea).

Concept Tested & Keywords

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