Fluid Management for Infants and Children

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Questions and Answers

How does the total body water (TBW) percentage change with age in children?

It remains constant throughout childhood.

It increases to match adult levels by age 12.

It decreases as the child ages. (correct)

It fluctuates significantly during the first year.

What is a characteristic of drug pharmacokinetics in children compared to adults?

The insensible water loss decreases as children get older.

Children have larger volumes of distribution for lipid soluble drugs.

Drug elimination half-lives are decreased in children.

Children exhibit higher free drug concentrations for highly protein-bound drugs due to decreased protein/immature liver function (correct)

At what age do children generally have an estimated blood volume of 80 mL/kg?

Newborns

3 months to 2 years (correct)

2 years and older (correct)

Preterm infants

What aspect of renal function is observed in the first year of life?

RBF and GFR are approximately half of adult values. Signup and view all the answers

What is the typical gastric emptying time for solid foods compared to clear liquids?

77-277 minutes for solids and 10-20 minutes for clear liquids Signup and view all the answers

Under what circumstances are preoperative fluids commonly indicated? select 3

For patients with endocrine/metabolic abnormalities Signup and view all the answers

Which population may require glucose-containing solutions during maintenance?

Debilitated infants or those small for their age Signup and view all the answers

What is a significant risk for neonates regarding fluid management?

Limited ability to handle sodium and risk of fluid overload Signup and view all the answers

What is the appropriate fluid replacement strategy for blood loss in pediatric patients? select 2

1:1 with blood or colloid Signup and view all the answers

Which factor contributes to the greater insensible water loss in neonates compared to older children?

Transepidermal water loss Signup and view all the answers

How does acute hypercarbia affect fluid distribution in the body?

Shrinks intracellular fluid and increases extracellular fluid Signup and view all the answers

What is the expected effect of delivery of cold, dry anesthetic gases via ETT on fluid loss?

Increases fluid loss from the respiratory tract by bypassing normal anatomic humidification Signup and view all the answers

What effect do opioids have on fluid retention in pediatric patients?

Increase ADH release which stimulates aldosterone - increased Na+ retention, K+ secretion Signup and view all the answers

What characteristic of blood volume makes pediatric patients more susceptible to dehydration? select 2

The younger the child, the higher the percentage of total body water Signup and view all the answers

What is a characteristic of water-soluble drugs in pediatric patients?

Greater volume of distribution (Vd) due to large total body water (TBW) content Signup and view all the answers

What can be expected when administering a water-soluble drug to a pediatric patient?

A larger volume of distribution (Vd) and may require a larger loading dose to achieve the desired plasma concentration. Signup and view all the answers

What is expected when administering a fat-soluble drug to a pediatric patient?

Higher plasma concentrations due to decreased fat and muscle volume Signup and view all the answers

What are the effects of immature renal function in pediatric patients? (Select all that apply)

Diminished ability to concentrate urine - increased free water loss Signup and view all the answers

Which two organs have immature function in pediatric patients that directly affect the pharmacokinetics and pharmacodynamics of drugs?

Kidneys and Liver Signup and view all the answers

Poiseuille's equation change in pressure = 8viscositylengthflow/piradius^4

True Signup and view all the answers

According to Poiseuille's law, what is flow directly proportional to?

Radius of the vessel to the fourth power Signup and view all the answers

According to Poiseuille's law, what is flow indirectly proportional to? select 2

Viscosity of the fluid Signup and view all the answers

When are isotonic fluids indicated?

All of the above Signup and view all the answers

What should glucose levels be maintained above to prevent neurological injury in infants and children?

45 mg/dL Signup and view all the answers

Why isn't hypoglycemia commonly seen in healthy surgical patients?

Surgical stress causes increased blood glucose secondary to cortisol Signup and view all the answers

How should intraoperative glucose be administered?

Using a rate-controlled pump Signup and view all the answers

Which of the following patients should receive glucose-containing solutions? select all that apply

Debilitated infants Signup and view all the answers

If a patient is above 20 kg, you should add 40 to their weight to calculate the hourly maintenance rate.

True Signup and view all the answers

What is third spacing?

Fluid accumulation in the interstitial space due to capillary leak and surgical trauma. Signup and view all the answers

What is virtual loss in the context of anesthesia?

Anesthetic-induced relaxation of sympathetic tone producing vasodilation and relative hypovolemia Signup and view all the answers

Why are premature infants more susceptible to volume overload?

They have low plasma osmotic pressure and low protein levels. Signup and view all the answers

Which of the following compensatory mechanisms occurs in response to acute hypercarbia? select 2

Bicarbonate shifts from the ICF to the ECF Signup and view all the answers

What is the effect of hypocarbia and hyperthermia on fluid shifts in the body?

Water, bicarbonate, and chloride move into the intracellular fluid, causing it to expand. Signup and view all the answers

What does a narrow pulse pressure indicate?

Reduced stroke volume Signup and view all the answers

What is a usual cause of reduced stroke volume in pediatric patients?

Dehydration Signup and view all the answers

What defines a narrow pulse pressure?

Pulse pressure less than 25% of systolic BP Signup and view all the answers

How many ml/kg should be administered in a fluid challenge?

10-20 ml/kg Signup and view all the answers

Study Notes

Infant (1-12 Months) and Child (1-12 Years) Fluid Management

Infants and young children have larger total body water (TBW) and extracellular fluid (ECF) compared to adults.
Fat and muscle increase with age, and body water content decreases.
Younger children have a higher percentage of total body water than older children.
Water-soluble drugs have a greater volume of distribution in children due to a dilutional effect.
A higher drug loading dose may be needed for water-soluble drugs in children to achieve desired plasma concentrations.
Lipid-soluble drugs have higher plasma concentrations in children due to decreased fat and muscle mass.

Estimating Blood Volume

Preterm: 90-100 mL/kg
Newborn: 80-90 mL/kg
3 months - 2 years: 80 mL/kg
2+ years: 80 mL/kg

Kidney Function

First-year renal blood flow (RBF) and glomerular filtration rate (GFR) are half of adult values.
Children have decreased ability to concentrate urine, leading to increased free water loss.
Preterm infants have increased sodium excretion and elevated serum creatinine.

Liver Function

Immature liver function in infants
Hepatic enzyme metabolism and blood flow are reduced (HBF).
Higher concentrations of highly protein-bound drugs in children.
Drug elimination half-lives are prolonged in infants.

Advantages of Limited NPO (Nothing by Mouth)

Less cranky, distressed children
Some evidence that clear liquids do not differ from gastric emptying comparison studies done (data is unclear, needs more robust studies)
Gastric emptying time for clear liquids is 10-20 minutes, and for solids it is 77-277 minutes (range difference).

Fluid Management/Replacement

Fluids are indicated for concurrent illness, poor nutrition states, hyperalimentation, and longer surgical procedures.
Consider the 4/2/1 rule for fluid replacement in children (age > 20 kg).
Replace blood loss with blood or colloids.
Replace blood or colloid loss 1:1 or 1:3 with crystalloid fluids dependent on the situation.
Third spacing occurs with capillary leak and surgical trauma.
Anesthetics can cause relative hypovolemia due to sympathetic tone relaxation.
High insensible water losses in neonates due to transepidermal water loss.
Exposed neonates have greater evaporative losses.
Premature infants have low plasma osmotic pressure and can easily develop edema due to fluid overload.

Fluid Choices

Isotonic fluids are used for surgical losses, deficits, and third spacing.
Glucose dextrose solutions.
Monitor for hypoglycemia and hyperglycemia in children (during the surgical procedure and post-op)
Give secondary IV fluids on a rate-controlled pump.
High glucose levels help prevent neurological injury.

Neonate Considerations

More susceptible to dehydration and fluid overload.
Limited ability to handle sodium loss.
Appropriate fluid management can prevent/treat issues (e.g., glycemic issues).

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Description

This quiz covers critical concepts in fluid management for infants and children aged 1 month to 12 years. It details total body water composition, the impact on drug dosing, and blood volume estimates based on age categories. Additionally, it explores kidney function in these age groups, emphasizing the differences compared to adults.