fluids and electrolytes

NRS 400

Why do fluids and electrolytes matter in high-acuity care?

They are foundational safety knowledge; small imbalances can have big consequences, and fluid/electrolyte imbalances can be either the cause or result of clinical deterioration.

What should high-acuity nurses do with fluid/electrolyte findings?

Spot subtle decline, link assessments to lab trends, and anticipate next steps.

What are the four major body fluid compartments listed?

Intracellular, interstitial, intravascular, and transcellular.

What are the two fluid movement processes emphasized?

Osmosis and diffusion.

In high-acuity care, where is fluid especially important to be?

Specifically intravascular, because intravascular volume is critical for perfusion.

Why do rapid fluid shifts occur in critical illness?

They can result from injury, the stress response, or interventions.

What organs are specifically dependent on adequate intravascular perfusion?

The brain, heart, and kidneys.

What can low intravascular volume cause?

Decreased perfusion and findings such as confusion, tachycardia, hypotension, and low urine output.

What happens when intravascular volume drops?

Tissues may receive less oxygen and nutrients.

What early nursing indicator should be trended to assess perfusion?

Urine output trend.

What other early indicators of perfusion changes should be watched?

Mental status changes; skin temperature, moisture, and capillary refill; and subtle blood-pressure changes, especially narrowing pulse pressure.

Why are IV fluids considered medications in acute/critical care?

They have specific indications, contraindications, and adverse effects.

What can fluid choice directly affect?

Cellular integrity, neurologic function, pulmonary status, and cardiovascular stability.

What is the nurse's role with IV fluids?

Understand why the fluid is ordered, monitor intended and unintended effects, and recognize early signs of harm.

What is the major cellular effect of hypotonic fluids?

Cell swelling.

What is the major high-acuity concern with hypotonic fluids?

Increased ICP and worsening cerebral edema.

Why are hypotonic fluids dangerous in neuro/trauma patients?

They can promote cellular swelling and worsen cerebral edema/increased ICP.

What hypotonic fluid example is listed?

0.45% sodium chloride.

What population is specifically identified as high risk with hypotonic fluids?

Patients with head injury/neurotrauma.

What is the major effect of isotonic fluids?

They increase volume without major fluid shifts between compartments.

What is the first-line use of isotonic fluids in high-acuity care?

Shock and trauma.

What major adverse effect can isotonic fluids cause?

They can worsen pulmonary edema/fluid overload.

What electrolyte-related complication can normal saline cause?

A chloride load can contribute to metabolic acidosis.

What isotonic fluid example is listed?

0.9% sodium chloride.

When should the nurse use caution with isotonic fluids?

In patients at risk for heart failure or fluid overload.

What is the major cellular effect of hypertonic fluids?

Cell shrinking.

What are high-acuity uses/impacts of hypertonic fluids?

ICP management and treatment of severe hyponatremia.

What vascular-access consideration is associated with hypertonic fluids?

Central-line considerations may apply.

Why are rapid sodium shifts dangerous?

They create a risk of osmotic demyelination.

Is hypertonic saline a maintenance fluid?

No. The lecture describes it as a rescue drug.

What hypertonic saline concentrations are shown in the lecture?

3% and 5% sodium chloride.

What major IV safety concern is noted for hypertonic saline?

It is described as a vesicant/high-risk IV medication that can damage tissue if it infiltrates.

When might colloids such as albumin be used in critical care?

Shock, burns, or hypoalbuminemia with third spacing.

Why is intravascular retention important with colloids?

The lecture emphasizes the importance of retaining fluid intravascularly during critical illness.

What colloid example is shown?

Albumin.

What is the key high-acuity approach to abnormal electrolytes?

Trend values, question outliers, and anticipate complications.

Why can electrolyte abnormalities be especially concerning?

They can precede clinical deterioration even when vital signs appear stable.

What question should nurses ask about an abnormal electrolyte?

What does this mean for safety right now?

What does potassium primarily represent in high-acuity assessment?

Electricity/arrhythmia risk.

What does sodium primarily represent?

Water/volume balance.

What are magnesium and calcium especially important for?

Rhythm stability and muscle function.

What is the normal potassium range listed?

3.5–5.0 mEq/L.

What is hypokalemia according to the lecture?

Potassium less than 3.5 mEq/L.

What potassium level is considered critically low?

Less than 2.4 mEq/L.

What is hyperkalemia according to the lecture?

Potassium greater than 5.0 mEq/L.

What potassium level is considered critically high?

Greater than 6.0 mEq/L.

Why can small serum potassium shifts be life-threatening?

Potassium is primarily intracellular, and small serum changes can trigger life-threatening dysrhythmias.

What must be assessed before giving potassium?

Renal function and urine output.

Why must renal function be assessed before potassium replacement?

If the kidneys are not functioning adequately, excess potassium may not be eliminated.

What should be monitored with potassium abnormalities?

ECG changes, muscle weakness, and overall instability.

What should be prioritized when potassium is abnormal in an unstable patient?

Potassium assessment and management.

What treatments are handwritten on the hyperkalemia portion of the lecture?

IV insulin/dextrose, calcium, and a potassium-binding medication (the slide notes a potassium binder).

What ECG concern is associated with hypokalemia?

ECG changes including rhythm abnormalities; the slide illustrates prolonged repolarization/QT-related changes.

What ECG findings are illustrated for hyperkalemia?

Peaked T waves, widened QRS, and other progressive conduction changes.

What is the normal sodium range listed?

135–145 mEq/L.

What is hyponatremia according to the lecture?

Sodium less than 135 mEq/L.

What sodium level is considered critically low?

Less than 120 mEq/L.

What is hypernatremia according to the lecture?

Sodium greater than 145 mEq/L.

What sodium level is considered critically high?

Greater than 160 mEq/L.

How should sodium be reframed in high-acuity care?

Think water balance and volume status, not just dietary salt.

What is the major neurologic risk of rapid sodium shifts?

Cerebral edema or osmotic demyelination.

Why does sodium correction speed matter?

Rapid correction can cause neurologic injury.

What assessment is especially important with sodium abnormalities?

Mental status.

What can mental-status changes guide in a patient with sodium abnormalities?

Urgency, fluid choice, and neurologic safety.

What conditions are handwritten as examples associated with sodium abnormalities?

SIADH and diabetes insipidus.

What is the normal magnesium range listed?

1.6–2.2 mEq/L.

What is hypomagnesemia according to the lecture?

Magnesium less than 1.6 mEq/L.

What magnesium level is critically low?

Less than 1.2 mEq/L.

What is hypermagnesemia according to the lecture?

Magnesium greater than 2.2 mEq/L.

What magnesium level is critically high?

Greater than 4.0 mEq/L.

What is the normal calcium range listed?

9.0–10.5 mg/dL.

What is hypocalcemia according to the lecture?

Calcium less than 9.0 mg/dL.

What calcium level is critically low?

Less than 7 mg/dL.

What is hypercalcemia according to the lecture?

Calcium greater than 10.5 mg/dL.

What calcium level is critically high?

Greater than 12 mg/dL.

What does low magnesium do to potassium replacement?

Low magnesium can prevent potassium repletion.

What does calcium support?

Muscle contraction and perfusion; it supports muscle squeeze and rhythm stability.

Why should Mg, K, and Ca be interpreted together?

They interact, so isolated values can be misleading.

What rhythm is specifically associated in the lecture with low magnesium?

Torsades de pointes.

What should a nurse do when potassium remains low despite replacement and magnesium is low?

Recognize that low magnesium may be preventing potassium repletion and address the magnesium problem.

What is trend thinking in critical care?

Integrating the whole clinical picture and tracking patterns over time rather than reacting to one isolated value.

What should be integrated when assessing fluid/electrolyte trends?

Vital signs, labs, urine output, intake/output, and the patient's response to interventions.

Why are trends more useful than one abnormal value?

Patterns over time can signal improvement or deterioration.

What does pattern recognition mean in critical-care nursing?

Recognizing clinically meaningful trends and changes across assessments and labs.

What does 'anticipate, don't chase' mean?

Use trend-based thinking to anticipate deterioration and support early escalation rather than waiting for severe abnormalities.

What high-acuity diagnosis is linked to volume, sodium, and potassium?

Shock.

What electrolyte/fluid issues are emphasized in DKA?

Potassium and fluid shifts.

What fluid/electrolyte issues are emphasized in trauma?

Intravascular volume, calcium, and transfusions.

What fluid issue is emphasized in respiratory failure?

Fluid balance.

What are the three tasks in the case-based application?

Recognize abnormal assessment findings, prioritize what to assess next, and anticipate fluid/electrolyte implications.

In the 72-year-old instability scenario, what findings are present?

Altered mental status, HR 128, BP 86/50, confusion/restlessness, urine output <30 mL/hr, rising creatinine, Na 132, and K 5.8.

In the 72-year-old scenario, which findings are most concerning?

The hypotension, tachycardia, altered mental status, low urine output, rising creatinine, and elevated potassium indicate significant instability.

What electrolyte is the immediate concern in the 72-year-old scenario?

Potassium, because K 5.8 mEq/L creates arrhythmia risk in an unstable patient.

What does low urine output plus rising potassium suggest in the 72-year-old scenario?

The kidneys are not functioning adequately and may not be excreting potassium effectively.

What type of fluid should the nurse be cautious with in the 72-year-old scenario?

Hypotonic fluid.

In the neuro-focused scenario, what findings are present?

A 59-year-old after a fall with worsening headache, confusion, vomiting, urine output >200 mL/hr, and sodium 118.

Why is hypotonic fluid dangerous in the neuro-focused scenario?

It can cause cell swelling and worsen cerebral edema/increased ICP.

What is the top safety concern in the neuro-focused scenario?

Neurologic deterioration/increased intracranial pressure.

Why must sodium correction be slow in the neuro-focused scenario?

Rapid fluid/sodium shifts can cause neurologic injury, including osmotic demyelination.

What assessment should be prioritized in the neuro-focused scenario?

Neurologic assessment.