IV Fluids Flashcards
What are crystalloids, and what are their primary components?
- Crystalloids are solutions containing small molecules that easily pass through vascular membranes.
- Common components: water, electrolytes (e.g., sodium, chloride), and sometimes glucose.
- Examples: 0.9% saline (normal saline), Hartmann’s solution, and 5% dextrose.
What distinguishes colloids from crystalloids?
- Colloids contain larger molecules (e.g., proteins or starches) that remain in the vascular space longer.
- Examples: albumin, hydroxyethyl starch (HES), and gelatins.
- Colloids are used for volume expansion but are more expensive and have a higher risk of complications.
What are the components of Hartmann’s solution, and when is it used?
- Components: Sodium, potassium, chloride, calcium, and lactate.
- Indications: Fluid resuscitation, electrolyte replacement, and correction of metabolic acidosis.
- Avoid in: Severe hyperkalemia or liver failure (due to impaired lactate metabolism).
List common indications for IV fluid therapy.
- Resuscitation: To restore circulating volume in hypovolemia or shock.
- Maintenance: To replace daily fluid and electrolyte requirements.
- Replacement: To correct specific deficits (e.g., from dehydration, vomiting, diarrhea).
- Special: Parenteral nutrition or specific conditions like hypertonic saline in hyponatremia.
What are the potential complications of IV fluid therapy?
- Volume overload: Pulmonary edema, peripheral edema.
- Electrolyte imbalances: Hypernatremia, hyponatremia, hyperkalemia.
- Acid-base disturbances: Metabolic acidosis (from 0.9% saline) or alkalosis (from excess bicarbonate).
- Infection: Related to IV access.
- Allergic reactions: More common with colloids.
Why is normal saline considered “isotonic,” and when is it commonly used?
- Isotonic because its osmolality is similar to plasma (~308 mOsm/L).
- Indications: Hypovolemia, metabolic alkalosis, and hyponatremia.
- Complication: Risk of hyperchloremic metabolic acidosis with large volumes.
What are the key uses of 5% dextrose in water (D5W)?
- Indications: Treat dehydration (when water is needed without electrolytes) or hypoglycemia.
- Complications: Can cause hyponatremia if used in excess due to dilutional effects.
How do you decide between crystalloids and colloids?
- Crystalloids: First-line for most indications (cheaper, fewer risks).
- Colloids: Reserved for specific cases like severe hypoalbuminemia or when rapid volume expansion is critical.
What are the differences between hypotonic and hypertonic solutions?
- Hypotonic: Lower osmolality than plasma (e.g., 0.45% saline). Used for intracellular dehydration.
- Hypertonic: Higher osmolality than plasma (e.g., 3% saline). Used cautiously for severe hyponatremia or cerebral edema.
What are crystalloids?
Solutions of small molecules that pass through vascular membranes.
Name 3 common crystalloid solutions.
Hartmann’s, 0.9% saline, and 5% dextrose.
What are isotonic crystalloids?
Solutions with an osmolality similar to plasma (e.g., Hartmann’s, 0.9% saline).
When are hypotonic crystalloids used?
Treating intracellular dehydration (e.g., 0.45% saline).
What is hypertonic saline used for?
Managing cerebral edema or severe hyponatremia.
What are colloids?
Fluids containing large molecules, remaining in the vascular space.
What are the risks of colloid use?
Allergic reactions, coagulopathy, and kidney injury.
When is albumin typically used?
Hypoalbuminemia, burns, or large-volume paracentesis.
Why are colloids not first-line in shock?
High cost and risk of adverse effects without clear survival benefit.
What are the main components of Hartmann’s solution?
Sodium, potassium, chloride, calcium, and lactate.
What is lactate in Hartmann’s metabolized into?
Bicarbonate, helping correct acidosis.
When should Hartmann’s be avoided?
Hyperkalemia or liver failure.
Is Hartmann’s suitable for blood transfusions?
No, due to calcium content that can cause clotting in blood products.
Why is Hartmann’s a balanced solution?
Electrolyte composition is closer to plasma than 0.9% saline.
What is the pH of 0.9% saline?
~5.5, slightly acidic.
What is hyperchloremic metabolic acidosis?
A complication of large-volume saline infusions.
When is saline preferred over Hartmann’s?
In hyperkalemia or alkalosis.
What is the sodium concentration in 0.9% saline?
154 mmol/L.
Can normal saline be used as maintenance fluid?
Yes, but monitor for hypernatremia.
What is 5% dextrose used for?
Providing free water for dehydration or hypoglycemia.
Why can dextrose cause hyponatremia?
Dilution of plasma sodium when metabolized.
What is 10% dextrose used for?
Treating hypoglycemia or as part of parenteral nutrition.
Can dextrose solutions provide significant caloric support?
Not alone; they lack sufficient energy for long-term needs.
When should dextrose be avoided?
In hypovolemic shock or brain injuries (risk of worsening edema).
What are maintenance fluids?
IV fluids given to meet daily fluid/electrolyte requirements.
What is fluid resuscitation?
Rapid fluid administration to correct hypovolemia or shock.
When is replacement fluid therapy needed?
To correct specific deficits (e.g., from diarrhea or bleeding).
What are special fluid therapies?
Hypertonic saline for hyponatremia, parenteral nutrition.
What are signs of dehydration needing IV fluids?
Dry mucous membranes, tachycardia, hypotension, reduced urine output.
What are common complications of fluid overload?
Pulmonary edema, peripheral edema, and hypertension.
How can IV fluids cause electrolyte imbalances?
Excess or deficient sodium, potassium, or chloride.
What are acid-base complications of IV fluids?
Metabolic acidosis (saline), alkalosis (bicarbonate excess).
What infection risks are associated with IV fluids?
Contamination of fluid or catheter-related bloodstream infections.
What is phlebitis?
Inflammation of a vein due to IV catheter placement.
How do you monitor for fluid overload?
Check for weight gain, crackles on auscultation, and raised JVP.
How is urine output monitored during IV fluid therapy?
Aim for >0.5 mL/kg/hour in adults.
What is the “4-2-1 rule”?
(Peads)
Maintenance fluids:
-4 mL/kg for the first 10 kg
-2 mL/kg for the next 10 kg
-1 mL/kg for every kg above 20.
What are the risks of rapid fluid administration?
Fluid overload, cardiac strain, or dilutional coagulopathy.
What is 3% hypertonic saline used for?
Severe hyponatremia or intracranial hypertension.
Why is 0.45% saline considered hypotonic?
Its osmolality is lower than plasma (~154 mOsm/L).
What is Plasmalyte?
A balanced crystalloid similar to Hartmann’s but without calcium.
What is TPN (total parenteral nutrition)?
A specialized solution providing all essential nutrients via IV.
When is 20% albumin used?
Severe hypoalbuminemia or fluid removal in cirrhosis with ascites.
What fluid is used in septic shock?
Balanced crystalloids like Hartmann’s or saline for initial resuscitation.
What fluid is ideal for trauma resuscitation?
Hartmann’s or blood products, depending on hemorrhage severity.
What is the risk of giving hypotonic fluids to a trauma patient?
Worsening cerebral edema.
What fluids are preferred in burns?
Balanced crystalloids (Hartmann’s) for resuscitation.
What is the role of dextrose in treating hypernatremia?
5% dextrose provides free water to gradually lower sodium levels.
