Examkin

Question

Difficulty: MediumPhysiological Adaptation

A triage nurse is evaluating a client who presents to the emergency department after 33 days of severe, continuous vomiting. The client reports an inability to keep any oral fluids down. Based on the client's presentation, which of the following clinical findings and laboratory results should the nurse anticipate? Select all that apply.

  1. Arterial blood gas pH of 7.527.52 and HCO3−HCO_3^- of 3434 mEq/LAnswer
  2. Serum potassium level of 2.82.8 mEq/LAnswer
  3. Narrowing pulse pressure with resting tachycardiaAnswer
  4. D
    Arterial blood gas PaCO2PaCO_2 of 2828 mm Hg
  5. E
    Bounding, +3+3 peripheral pulses

Answer

The anticipated findings are metabolic alkalosis (elevated pH and HCO3−HCO_3^-), hypokalemia (low potassium), and signs of hypovolemia (narrowing pulse pressure and tachycardia).
Severe, continuous vomiting causes significant loss of gastric acid, leading to metabolic alkalosis, which is reflected by an elevated pH (7.527.52) and elevated bicarbonate (3434 mEq/L). Additionally, gastric fluid loss and secondary hyperaldosteronism from hypovolemia result in potassium depletion (hypokalemia). The profound fluid volume deficit decreases stroke volume, causing a compensatory resting tachycardia and a narrowing pulse pressure as the body attempts to maintain perfusion.

Step-by-Step Solution

1
Analyze the physiological impact of severe vomiting.
Vomiting causes massive loss of fluid, potassium, and gastric acid.
Gastric secretions are highly acidic (rich in hydrogen ions) and contain significant amounts of potassium and chloride.
2
Determine the expected acid-base and electrolyte imbalances.
Loss of hydrogen ions leads to metabolic alkalosis. Potassium loss leads to hypokalemia (<3.5< 3.5 mEq/L).
The body loses acid directly. Furthermore, the resulting fluid volume deficit triggers aldosterone release, which causes the kidneys to retain sodium and excrete even more potassium.
3
Evaluate the expected hemodynamic and compensatory changes.
Fluid loss causes hypovolemia, resulting in weak pulses, tachycardia, and a narrowing pulse pressure. The respiratory system compensates for alkalosis by hypoventilating, not hyperventilating.
Hypovolemia decreases cardiac output, prompting sympathetic nervous system activation (tachycardia, vasoconstriction). Hypoventilation helps the body retain CO2CO_2 to lower the pH.

Key Concept

Physiological adaptation to severe fluid and acid loss (Metabolic alkalosis and hypovolemia)
Estimated Time:1m 30s
Rate this question

Topics

Physiological Adaptation

More questions from this topic