Pediatric Clinical Practice Guidelines for Nurses in Primary Care

Chapter 4 - Fluid Management

Fluid Management

• Fluid Requirements in Children
• Dehydration in Children

Fluid Management

Fluid Requirements in Children

General Information

Maintenance fluid is the amount of fluid the body needs to replace usual daily losses from the respiratory tract, the skin, and the urinary and GI tracts.

A well child usually drinks more than maintenance requirements. If a child takes in significantly less than maintenance requirements, he or she will gradually become dehydrated.

The requirement for maintenance fluids varies with the weight of the child (Table 4-1). Infants need more fluid per kilogram of body weight than do older children. Various medical conditions will also affect these requirements (Table 4-2).

Table 4-1: Daily Maintenance Fluid Requirements
(24-Hour Period)

Calculation

• 100 mL/kg for the first 10 kg body weight
• + 50 mL/kg for the next 10 kg body weight
• + 20 mL for each kilogram of body weight over 20 kg

Examples

• For 10-kg child: 10 kg × 100 mL/kg = 1000 mL
• For 15-kg child: (10 kg × 100 mL/kg) + (5 kg × 50 mL/kg) =
  1250 mL
• For 25-kg child: (10 kg × 100 mL/kg) + (10 kg × 50 mL/kg)
  + (5 kg × 20 mL/kg) = 1600 mL

Table 4-2: Conditions Modifying Daily Fluid Requirements

Requirement Increased

• Fever,* sweating, vomiting or diarrhea
• Diabetes
• Burns

Requirement Decreased

• Meningitis
• Congestive heart failure
• Renal failure

*Daily maintenance fluids should be increased by 12% for every degree Celsius body temperature above 37.5°C (rectal).

Dehydration in Children

Definition

Abnormal decrease in volume of circulating plasma.

Causes

• Gastroenteritis (most common cause in childhood)
• Inadequate fluid intake
• Diabetes mellitus
• Burns
• Pyloric stenosis
• GI obstruction

Newborns and young children have a much higher water content than adolescents and adults and are therefore more prone to loss of water, sodium and potassium during illness.

History

• Fever
• Vomiting
• Diarrhea
• Urine output
• Lethargy
• Irritability

All body systems must be reviewed to ascertain underlying cause.

Physical Findings

Table 4-3 presents the clinical features of various stages of dehydration.

Diagnostic Tests

• Urinalysis to check for ketones
• Blood glucometry to rule out diabetes (if no diarrhea)

Management

Goals of Treatment

• Correct dehydration using oral rehydration therapy (ORT) with or without IV fluids
• Treat shock or impending shock
• Prevent complications (e.g., seizures or edema)

Appropriate Consultation

Consult a physician as soon as possible for any infant or young child with signs of dehydration. If the child has presented with severe signs (e.g., shock), this consultation may have to wait until the child's condition has been stabilized.

Nonpharmacologic Interventions

• Using the criteria presented in Table 4-3, decide if child is mildly, moderately or severely dehydrated.
• Weigh child (without clothes).
• Once you have determined the degree of dehydration, calculate the fluid deficit according to Table 4-4 (using the percent dehydration values shown in the column headings for Table 4-3). When you have calculated the deficit, add maintenance requirements (see Tables 4-1 and 4-2) and rehydrate according to Table 4-5.

Monitoring and Follow-Up

Reassess level of consciousness (according to pediatric Glasgow coma scale, Table 15-1, in chapter 15, "Central Nervous System"), vital signs, skin perfusion, skin turgor and urine output frequently.

Referral

Medevac any child with moderate to severe dehydration as soon as possible.

*Skin condition is less useful in diagnosis of dehydration in children >2 years of age.

Table 4-4: Calculating Fluid Deficit

Calculation

Fluid deficit (L) = weight (kg) × % dehydration

Example

For an 8-kg child with 10% dehydration:
8 kg x 10% = 0.8 L deficit

Table 4-5: Fluid Resuscitation

Mild Dehydration (<5%)

• Start ORT: 10 mL/kg for 6--8 hours
• Reassess at 4-hour intervals
• From 8 to 24 hours, give ORT ad libitum
• Give fluid frequently, in small amounts
• Replace deficit over 6--8 hours (add maintenance requirement to deficit)
• Give extra ORT after each diarrheal stool (e.g., 5--10 mL/kg)
• Monitor urine output (output should be at least 1 mL/kg body weight per hour)
• Continue breast-feeding; if child is bottlefed, early refeeding of child's normal formula (within 6--12 hours) is recommended
• Full diet should be reinstituted within 24--48 hours, if possible
• Delay refeeding only if there is severe, protracted vomiting

Moderate Dehydration (5% to 10%)

• Attempt ORT as in mild dehydration: 15--20 mL/kg for 6--8 hours
• Reassess at 4-hour intervals
• From 8 to 24 hours, give ORT ad libitum
• Give fluid frequently, in small amounts
• Replace deficit over 6--8 hours (add maintenance requirement to deficit)
• Give extra ORT after each diarrheal stool (e.g., 5--10 mL/kg)
• Monitor urine output (output should be at least 1 mL/kg body weight per hour)
• Continue breast-feeding; if child is bottlefed, early refeeding of child's normal formula (within 6--12 hours) is recommended
• Full diet should be reinstituted within 24--48 hours, if possible
• Delay refeeding only if there is severe, protracted vomiting

Severe Dehydration (>10%)

• Medical emergency
• NS or Ringer's lactate 20 mL/kg IV over 20 minutes
• Monitor blood pressure
• Repeat bolus (to a maximum of three boluses in 1 hour) if signs of shock persist (e.g., tachycardia, decreased systolic blood pressure, poor perfusion, skin gray and mottled)
• Once response occurs, calculate remaining deficit: replace 50% of the eficit over 8 hours, remainder over next 16 hours (be sure to add maintenance requirements to total IV therapy)
• Monitor urine output (output should be at least 1 mL/kg body weight per hour)
• If unable to start an IV line in three attempts (or within 60--90 seconds), establish intraosseous access
• For intraosseous infusion, see "Intraosseous Access," in chapter 2, "Pediatric Procedures"); this technique can save the child's life and is not technically difficult; when line is in place, use as you would a regular IV line

ORT = oral rehydration therapy, NS = normal saline, IV = intravenous.

General Comments about Fluid Management

IV therapy should usually be used only for severe dehydration or intractable vomiting; oral therapy is always safer. However, the oral replacement solution (ORS) may be administered by nasogastric tube if necessary.

Use an ORS such as Pedialyte or Gastrolyte to replace the calculated deficit.

If the child is breast-feeding and is able to nurse, then breast-feeding should be continued for maintenance requirements; supplement with Pedialyte or Gastrolyte to make up the deficit.

Increase the amount of maintenance fluids if there are ongoing fluid losses (e.g., if diarrhea continues).

If a marked increase in diarrhea occurs when a bottle-fed child returns to his or her usual cow's milk formula, consult a physician about changing to a soy-based formula (e.g., Prosobee or Isomil). Switch back to regular cow's milk formula within 7-10 days. Do not go back to Pedialyte unless there is a marked increase in stools while on soy formula. Some increase in stools does not matter, as long as the child takes in enough to keep up with losses. In other words, treat on the basis of the child's condition, not on the basis of the stools.

If the child is vomiting, he or she will usually tolerate fluids by mouth if given in small amounts (one sip at a time). If child will not suck, try giving sips frequently by spoon. Allow mother and other family members to administer fluid. Increase daily maintenance fluids by 12% for every degree Celsius body temperature above 37.5°C (rectal).