IV Fluids

Question 1

What are crystalloids, and what are their primary components?

Answer 1

• 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.

Question 2

What distinguishes colloids from crystalloids?

Answer 2

• 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.

Question 3

What are the components of Hartmann’s solution, and when is it used?

Answer 3

• 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).

Question 4

List common indications for IV fluid therapy.

Answer 4

• 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.

Question 5

What are the potential complications of IV fluid therapy?

Answer 5

• 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.

Question 6

Why is normal saline considered “isotonic,” and when is it commonly used?

Answer 6

• 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.

Question 7

What are the key uses of 5% dextrose in water (D5W)?

Answer 7

• Indications: Treat dehydration (when water is needed without electrolytes) or hypoglycemia.
• Complications: Can cause hyponatremia if used in excess due to dilutional effects.

Question 8

How do you decide between crystalloids and colloids?

Answer 8

• Crystalloids: First-line for most indications (cheaper, fewer risks).
• Colloids: Reserved for specific cases like severe hypoalbuminemia or when rapid volume expansion is critical.

Question 9

What are the differences between hypotonic and hypertonic solutions?

Answer 9

• 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.

Question 10

What are crystalloids?

Answer 10

Solutions of small molecules that pass through vascular membranes.

Question 11

Name 3 common crystalloid solutions.

Answer 11

Hartmann’s, 0.9% saline, and 5% dextrose.

Question 12

What are isotonic crystalloids?

Answer 12

Solutions with an osmolality similar to plasma (e.g., Hartmann’s, 0.9% saline).

Question 13

When are hypotonic crystalloids used?

Answer 13

Treating intracellular dehydration (e.g., 0.45% saline).

Question 14

What is hypertonic saline used for?

Answer 14

Managing cerebral edema or severe hyponatremia.

Question 15

What are colloids?

Answer 15

Fluids containing large molecules, remaining in the vascular space.

Question 16

What are the risks of colloid use?

Answer 16

Allergic reactions, coagulopathy, and kidney injury.

Question 17

When is albumin typically used?

Answer 17

Hypoalbuminemia, burns, or large-volume paracentesis.

Question 18

Why are colloids not first-line in shock?

Answer 18

High cost and risk of adverse effects without clear survival benefit.

Question 19

What are the main components of Hartmann’s solution?

Answer 19

Sodium, potassium, chloride, calcium, and lactate.

Question 20

What is lactate in Hartmann’s metabolized into?

Answer 20

Bicarbonate, helping correct acidosis.

Question 21

When should Hartmann’s be avoided?

Answer 21

Hyperkalemia or liver failure.

Question 22

Is Hartmann’s suitable for blood transfusions?

Answer 22

No, due to calcium content that can cause clotting in blood products.

Question 23

Why is Hartmann’s a balanced solution?

Answer 23

Electrolyte composition is closer to plasma than 0.9% saline.

Question 24

What is the pH of 0.9% saline?

Answer 24

~5.5, slightly acidic.

Question 25

What is hyperchloremic metabolic acidosis?

Answer 25

A complication of large-volume saline infusions.

Question 26

When is saline preferred over Hartmann's?

Answer 26

In hyperkalemia or alkalosis.

Question 27

What is the sodium concentration in 0.9% saline?

Answer 27

154 mmol/L.

Question 28

Can normal saline be used as maintenance fluid?

Answer 28

Yes, but monitor for hypernatremia.

Question 29

What is 5% dextrose used for?

Answer 29

Providing free water for dehydration or hypoglycemia.

Question 30

Why can dextrose cause hyponatremia?

Answer 30

Dilution of plasma sodium when metabolized.

Question 31

What is 10% dextrose used for?

Answer 31

Treating hypoglycemia or as part of parenteral nutrition.

Question 32

Can dextrose solutions provide significant caloric support?

Answer 32

Not alone; they lack sufficient energy for long-term needs.

Question 33

When should dextrose be avoided?

Answer 33

In hypovolemic shock or brain injuries (risk of worsening edema).

Question 34

What are maintenance fluids?

Answer 34

IV fluids given to meet daily fluid/electrolyte requirements.

Question 35

What is fluid resuscitation?

Answer 35

Rapid fluid administration to correct hypovolemia or shock.

Question 36

When is replacement fluid therapy needed?

Answer 36

To correct specific deficits (e.g., from diarrhea or bleeding).

Question 37

What are special fluid therapies?

Answer 37

Hypertonic saline for hyponatremia, parenteral nutrition.

Question 38

What are signs of dehydration needing IV fluids?

Answer 38

Dry mucous membranes, tachycardia, hypotension, reduced urine output.

Question 39

What are common complications of fluid overload?

Answer 39

Pulmonary edema, peripheral edema, and hypertension.

Question 40

How can IV fluids cause electrolyte imbalances?

Answer 40

Excess or deficient sodium, potassium, or chloride.

Question 41

What are acid-base complications of IV fluids?

Answer 41

Metabolic acidosis (saline), alkalosis (bicarbonate excess).

Question 42

What infection risks are associated with IV fluids?

Answer 42

Contamination of fluid or catheter-related bloodstream infections.

Question 43

What is phlebitis?

Answer 43

Inflammation of a vein due to IV catheter placement.

Question 44

How do you monitor for fluid overload?

Answer 44

Check for weight gain, crackles on auscultation, and raised JVP.

Question 45

How is urine output monitored during IV fluid therapy?

Answer 45

Aim for >0.5 mL/kg/hour in adults.

Question 46

What is the "4-2-1 rule"? (Peads)

Answer 46

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.

Question 47

What are the risks of rapid fluid administration?

Answer 47

Fluid overload, cardiac strain, or dilutional coagulopathy.

Question 48

What is 3% hypertonic saline used for?

Answer 48

Severe hyponatremia or intracranial hypertension.

Question 49

Why is 0.45% saline considered hypotonic?

Answer 49

Its osmolality is lower than plasma (~154 mOsm/L).

Question 50

What is Plasmalyte?

Answer 50

A balanced crystalloid similar to Hartmann's but without calcium.

Question 51

What is TPN (total parenteral nutrition)?

Answer 51

A specialized solution providing all essential nutrients via IV.

Question 52

When is 20% albumin used?

Answer 52

Severe hypoalbuminemia or fluid removal in cirrhosis with ascites.

Question 53

What fluid is used in septic shock?

Answer 53

Balanced crystalloids like Hartmann's or saline for initial resuscitation.

Question 54

What fluid is ideal for trauma resuscitation?

Answer 54

Hartmann's or blood products, depending on hemorrhage severity.

Question 55

What is the risk of giving hypotonic fluids to a trauma patient?

Answer 55

Worsening cerebral edema.

Question 56

What fluids are preferred in burns?

Answer 56

Balanced crystalloids (Hartmann’s) for resuscitation.

Question 57

What is the role of dextrose in treating hypernatremia?

Answer 57

5% dextrose provides free water to gradually lower sodium levels.