Fluids and When to Use
A patient has experienced vomiting and diarrhea for three days. The blood pressure is 86/50 mm Hg, the heart rate is 118/min, and the patient has dry mucous membranes. Name one appropriate type of IV solution for initial fluid-volume replacement.
Answer: An isotonic crystalloid, such as 0.9% sodium chloride or lactated Ringer’s solution.
Rationale: The patient has hypovolemia and hypotension. Isotonic solutions remain primarily in the extracellular compartment and expand circulating volume. They are commonly used for initial fluid resuscitation
A patient’s potassium level is 2.8 mEq/L. The patient reports muscle weakness and leg cramps. Is this hypokalemia or hyperkalemia?
Answer: Hypokalemia.
Rationale: A potassium level of 2.8 mEq/L is below the expected range. Hypokalemia can cause weakness, muscle cramps, constipation, reduced bowel motility, and cardiac dysrhythmias.
A patient has tremors, hyperreflexia, and a magnesium level of 1.2 mg/dL. Is this hypomagnesemia or hypermagnesemia?
Answer: Hypomagnesemia.
Rationale: A magnesium level of 1.2 mg/dL is low. Neuromuscular excitability, tremors, hyperreflexia, seizures, and ventricular dysrhythmias can occur. Magnesium abnormalities can also contribute to abnormal potassium and calcium levels
A patient’s sodium level is 128 mEq/L. Is this hyponatremia or hypernatremia?
Answer: Hyponatremia.
Rationale: A sodium level of 128 mEq/L is below the expected range of approximately 135–145 mEq/L. Neurological manifestations become more likely as the sodium decreases or falls rapidly.
Interpret this ABG:
Answer: Uncompensated respiratory acidosis.
Rationale: The pH is acidic and the PaCO₂ is elevated, identifying a respiratory cause. The bicarbonate remains normal, so metabolic compensation has not yet occurred.
This IV fluid contains sodium, chloride, potassium, calcium, and lactate. It is commonly used for fluid resuscitation following blood loss, surgery, trauma, or dehydration.
Answer: Lactated Ringer’s solution.
Rationale: Lactated Ringer’s is a balanced isotonic crystalloid containing sodium, chloride, potassium, calcium, and lactate. It is frequently used to replace fluid and electrolyte losses.
A patient taking furosemide has a potassium level of 3.0 mEq/L. Name one food the nurse could recommend that is high in potassium.
Answer: Acceptable responses include bananas, oranges, potatoes, tomatoes, avocados, spinach, beans, dried fruit, or melon.
Rationale: Loop diuretics such as furosemide increase urinary potassium loss. Dietary potassium may help with mild deficits when the patient does not have kidney failure or another reason to restrict potassium.
A patient receiving IV magnesium sulfate develops absent deep-tendon reflexes, respiratory depression, and hypotension. What electrolyte imbalance should the nurse suspect?
Answer: Hypermagnesemia or magnesium toxicity.
Rationale: Excess magnesium suppresses neuromuscular and cardiac function. Findings may include diminished or absent reflexes, lethargy, hypotension, bradycardia, and respiratory depression.
A patient has intense thirst, dry mucous membranes, restlessness, and a sodium level of 153 mEq/L. Identify the electrolyte imbalance.
Answer: Hypernatremia.
Rationale: Hypernatremia commonly represents a water deficit relative to sodium. Manifestations may include thirst, dry mucous membranes, agitation, restlessness, weakness, confusion, seizures, and coma.
Answer: Uncompensated respiratory alkalosis.
Rationale: The pH is alkalotic and the PaCO₂ is low. A low PaCO₂ results from excessive ventilation and indicates a respiratory cause. The bicarbonate remains normal, showing no metabolic compensation. Treatment focuses on correcting the cause of hyperventilation.
A patient with hypernatremia has adequate blood pressure and no evidence of shock. The provider prescribes a solution that supplies more free water and moves water into dehydrated cells. Identify one solution that may be used.
Answer: A hypotonic solution, such as 0.45% sodium chloride.
Rationale: After circulating volume and blood pressure are stable, hypotonic fluid may be used to replace free-water deficits in hypernatremia. Hypotonic fluids move water from the vascular space toward the intracellular space. They are not appropriate for initial shock resuscitation.
A patient with kidney failure has a potassium level of 6.6 mEq/L and tall, peaked T waves. What is the nurse’s first monitoring priority?
Answer: Place the patient on continuous cardiac monitoring and obtain or review an ECG.
Rationale: Severe hyperkalemia can produce life-threatening cardiac conduction changes. Tall, peaked T waves may progress to PR prolongation, QRS widening, ventricular dysrhythmias, or cardiac arrest.
A patient has tingling around the mouth, muscle cramps, and a positive Trousseau sign. Which electrolyte is most likely low?
Answer: Calcium.
Rationale: Hypocalcemia increases neuromuscular excitability. Manifestations include perioral numbness, tingling, muscle cramps, tetany, seizures, and positive Chvostek or Trousseau signs.
A patient with severe hyponatremia becomes confused and has a seizure. What is the nurse’s immediate safety intervention?
Answer: Institute seizure precautions and protect the patient from injury while maintaining the airway.
Rationale: Severe hyponatremia can cause cerebral edema and seizures. Immediate priorities are airway protection, seizure safety, neurological assessment, and prompt notification of the provider or rapid-response team.
Answer: Uncompensated metabolic acidosis.
Rationale: The pH is acidic and the bicarbonate is low, identifying a metabolic cause. The PaCO₂ remains within the expected range, so respiratory compensation is not evident.
A patient has acute symptomatic hyponatremia with seizures and a sodium level of 113 mEq/L. Which IV solution should the nurse anticipate?
Answer: 3% sodium chloride.
Rationale: Hypertonic saline may be used for severe symptomatic hyponatremia, particularly when neurological symptoms such as seizures are present. Sodium must be corrected carefully because overly rapid correction can cause serious neurological injury
The provider prescribes IV regular insulin and dextrose for a patient with severe hyperkalemia. Explain why these medications are given together.
Answer: Insulin moves potassium from the blood into the cells, and dextrose prevents or treats insulin-induced hypoglycemia.
Rationale: This treatment temporarily lowers the serum potassium by shifting potassium intracellularly. It does not remove potassium from the body, so additional potassium-removal treatment may be necessary.
A patient with malignancy has a calcium level of 13.2 mg/dL, constipation, confusion, and excessive thirst. Identify the electrolyte disorder.
Answer: Hypercalcemia.
Rationale: Hypercalcemia can cause weakness, constipation, nausea, polyuria, excessive thirst, kidney stones, confusion, and dysrhythmias. Malignancy is an important potential cause.
A patient with prolonged vomiting has a chloride level of 87 mEq/L and an elevated bicarbonate level. Which acid–base imbalance commonly accompanies this chloride loss?
Answer: Metabolic alkalosis.
Rationale: Prolonged vomiting causes loss of gastric hydrochloric acid. The resulting loss of hydrogen and chloride contributes to hypochloremic metabolic alkalosis.
Answer: Partially compensated metabolic alkalosis.
Rationale: The pH remains alkalotic and the bicarbonate is elevated, identifying metabolic alkalosis. The PaCO₂ is also elevated because the respiratory system is retaining carbon dioxide to compensate. Because the pH has not returned to normal, compensation is partial.
A patient with traumatic brain injury has increased intracranial pressure. The provider orders a solution that pulls water out of swollen brain cells and into the vascular space. Identify the type of solution and one example.
Answer: A hypertonic solution, such as 3% sodium chloride.
Rationale: Hypertonic saline draws water from swollen cells into the vascular compartment. It may be prescribed to reduce cerebral edema and increased intracranial pressure. The nurse must closely monitor sodium, neurological status, lung sounds, and fluid balance.
A patient with severe hyperkalemia has widening of the QRS complex. Which IV medication may be given to stabilize the cardiac membrane without directly lowering the serum potassium?
Answer: IV calcium gluconate or calcium chloride.
Rationale: IV calcium stabilizes the myocardial cell membrane and reduces the immediate risk of fatal dysrhythmia. It does not lower the potassium level, so insulin, dextrose, beta-agonists, potassium binders, diuretics, or dialysis may also be required.
A patient has severe hypermagnesemia with respiratory depression and bradycardia. Which medication should the nurse anticipate as an antagonist to magnesium?
Answer: Calcium gluconate.
Rationale: Calcium gluconate antagonizes the effects of magnesium on the heart and neuromuscular system. Additional interventions may include stopping magnesium sources, supporting respirations, administering fluids and diuretics when appropriate, and dialysis for severe toxicity with kidney failure.
A patient receives several liters of 0.9% sodium chloride and develops a chloride level of 116 mEq/L and a low bicarbonate level. Which acid–base imbalance should the nurse suspect?
Answer; Metabolic acidosis
Rationale: Prolonged vomiting causes loss of gastric hydrochloric acid. The resulting loss of hydrogen and chloride contributes to hypochloremic metabolic alkalosis.
Answer: Fully compensated respiratory acidosis.
Rationale: The pH is within the normal range but is on the acidic side of 7.40. The PaCO₂ is elevated, identifying respiratory acidosis. The bicarbonate is also elevated because the kidneys have retained bicarbonate. The normal pH indicates full compensation.