CPS Statement: Maintenance Intravenous Fluids

CPS Statement: Maintenance Intravenous Fluids

The following was adapted from the Canadian Pediatric Society’s statement on "Risk of acute hyponatremia in hospitalized children and youth receiving maintenance intravenous fluids." Please see the full statement for the full recommendations from the Canadian Pediatric Society.

Background:

Hyponatremia is defined as a serum sodium (Na) level of less than 135 mmol/L. Hyponatremia is described as acute if it develops in less than 48 hours.  Acute hyponatremia can lead to cerebral edema which presents initially with headache and lethargy but can progress to seizures and cardiorespiratory arrest from brain stem herniation.

Recent studies have shown that hospitalized children who receive maintenance intravenous (IV) fluids are at an increased risk of hyponatremia, with 9-24% of these children developing hyponatremia to some degree. This risk stems from two factors:

  • It was routine practice to give children hypotonic IV solutions with 20-30 mmol/L of Na.
  • Hospitalized children are at an increased risk of developing elevated ADH secretion due to nausea, stress, pain and medications like morphine.  There is a particular risk in children who undergo surgery or have acute pulmonary and central nervous system infections (eg. Meningitis, encephalitis, pneumonia, bronchiolitis.)

Essentially, sodium is being diluted by hypotonic IV fluids, and water is being retained by increased ADH secretion.  With too little sodium coming in, and not enough water going out, hyponatremia can develop.

New studies have shown that giving children isotonic maintenance IV solutions with 0.9% NaCl can reduce the risk of hyponatremia without significantly increasing the risk of hypernatremia (serum Na > 145 mmol/L.) As long as the child is not severely dehydrated, and does not have a problem eliminating sodium from the kidney, hypernatremia is unlikely.

TABLE 2
Commonly used intravenous fluids
Fluid
Na mmol/L
K mmol/L
CI mmol/L
Lactate mmol/L
Dextrose gram/L
Tonicity versus plasma
D5W.0.9% NaCl
(D5NS)
154
0
154
0
50
Isotonic
D5W.0.45% NaCl
(D5 1/2NS)
77
0
77
0
50
Half-isotonic (hypotonic)
D5W.0.2% NaCl
33
0
33
0
50
Hypotonic
2/3–1/3
45
0
45
0
33
Hypotonic
Ringer’s Lactate
130
4
110
28
0
Isotonic

Recommendations:

These recommendations apply to hospitalized children aged 1 month to 18 years receiving maintenance IV fluids.  They do not apply to patients with renal or cardiac disease, diabetic ketoacidosis, severe burns or other conditions that affect electrolyte regulation.

General Principles:

  • 1) All hospitalized children receiving IV fluids are at risk for hyponatremia.  There is a high risk in those undergoing surgery, or with acute neurologic or respiratory infections.
  • 2) Oral fluids are generally hypotonic and should be accounted for when assessing total fluid intake (TFI).
  • 3) Infants and young children require dextrose with maintenance fluids (eg. D5NS) as they have limited glycogen stores.
  • 4) Clinicians should be equally cautious when prescribing IV fluids as they are when prescribing medications.

Monitoring:

  • 1) Before starting fluids, measure baseline serum electrolytes, glucose, urea, and creatinine.
  • 2) Check electrolytes regularly. In children with particular risk of increased ADH secretion, they should be checked daily or more frequently if indicated.
  • 3) Monitor intake, outputs and daily weights.
  • 4) Be aware of the symptoms of hyponatremia.

Prescription of IV Fluids for Maintenance Requirements in Hospitalized Children:

  • 1) Normal Na, and high risk of increased ADH secretion - Use D5NS
  • 2) Normal Na, and normal risk - Use D5NS (preferred) or D5 1/2NS
  • 3) Hypotonic fluids with less than 0.45% NaCL should not be used for routine fluid maintenence.
  • 4) Unknown Na levels - Use D5NS
  • 5) Elevated Na (145-154 mmol/L) - Use D5W 1/2NS
  • 6) Ringer's Lactate is generally not appropriate as a maintenance fluid in children.

Last updated by PedsCases: February 16, 2015.

Physiologic System: 
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