Fluids and Electrolytes Therapy in Paediatrics

Arravindh Vivekananthan

Body Composition

Water; main constituent of the body.

Initially, fetus has high TBW. Term infant has 75%.

1st year of life; decreases to 60%, maintains till puberty.

MALE (60%) vs FEMALE (50%)

• Normal daily fluid requirements for children are higher than those of adults due to greater insensible losses.

• Infants a limited ability to concentrate urine due to immature kidneys.

• Total body water is a higher percentage of body weight (75% in children vs. 60% in adults)

• Postoperative fluid replacement should be adjusted to support urine output between 1 and 2 mL/kg/hour.

Total Body Water

Composition of Solute

ICFPotassium, protein, phosphate_______________________Na+,K+-ATPase pump -----------------------------------

ECFSodium, Chloride

Maintenance Fluid

• Maintenance intravenous (IV) fluids are used in children who cannot be fed enterally.

• Maintenance fluid is the volume of daily fluid intake.

• Maintenance fluids are composed of a solution of water, glucose, sodium, potassium, and chloride. This solution replaces electrolyte losses from the urine and stool, as well as water losses from the urine, stool, skin, and lungs. EX : Normal saline, ringer lactate

provides approximately 20% of the normal caloric needs of the patient.

to prevent the development of starvation ketoacidosis and diminishes the protein degradation.

Measurable/non- measurable

• 5% dextrose (D5) in 1⁄4 normal saline (NS) + 20 mEq/L of potassium chloride (KCl)

• D5 in 1⁄2 NS + 20 mEq/L of KCl.

• high risk of hyponatremia should be given isotonic solutions (i.e. 0.9% saline ± glucose)

• Daily potassium requirements are 1 to 2 mEq/kg.

• Daily sodium requirements are 2 to 3 mEq/kg.

Children weighing <10 kg/6 mo. do best with the solution containing 1⁄4 NS (38.5 mEq/L) because of their high

water needs per kilogram. In contrast, >10 kg/6 mo. may receive the solution with 1⁄2 NS (77 mEq/L).

DEHYDRATION AND REPLACEMENT THERAPY

Normal source of water loss

clinical situations

1.premature infants

2.BURN : FLUID/ELECTROLYTES

3.FEVER : INSENSIBLE LOSS

4.EVAPORATIVE LOSS

5.DM, D.Insipidus, ATN

6.Drains; measured, replaced

7.Edema,ascites. Cant quantify, but anticipate in burn, abd. surgeries

• Studies indicate that clear liquids ingested 2 hours before induction of anesthesia do not increase the risk of aspiration in children at normal risk of aspiration during anesthesia.

• In addition, children permitted fluids in a less restrictive fashion have a more comfortable preoperative experience in terms of thirst and hunger

(Cochrane Database Syst Rev. 2009;(4):CD005285).

Nil-by-Mouth Status.

DEFICIT

assess the degree of dehydration urgency of the situation and the volume of fluid needed for rehydration

Hypotension indicates organ hypoperfusion Shock

immediate and aggressive intravenous therapy is indicated

Minimum urine outputshould be 1-2 mls/kg /hr.

Calculation of Fluid Deficit

percentage of dehydration multiplied by the patient’s weight

(for a 10-kg child, 10% x 10 kg =1 L deficit)

rapid restoration of the circulating intravascular volume, which should be done with an isotonic solution, such as

normal saline (NS) or Ringer’s lactate.

• fluid bolus, usually 20 mL/kg of the isotonic solution, over about 20 minutes.

• severe dehydration may require multiple fluid boluses and may need to receive fluid at a faster rate.

Improvement of vital signs plan the fluid therapy for the next 24 hours

To ensure that the intravascular volume is restored,

Ongoing losses (e.g. from drains, ileostomy, profuse diarrhea)

• These are best measured and replaced. Any fluid losses > 0.5ml/kg/hr needs to be replaced.

• Calculation may be based on each previous hour, or each 4 hour period depending on the situation. For example; a 200mls loss over the previous 4 hours will be replaced with a rate of 50mls/hr for the next 4 hours).

• Ongoing losses can be replaced with 0.9% Normal Saline or Hartmann’s solution. Fluid loss with high protein content leading to low serum albumin (e.g. burns) can be replaced with 5% Human Albumin.

References

1. Nelson Essentials of Pediatrics, 7th Edition

2. PAEDIATRIC PROTOCOLS For Malaysian Hospitals, 3rd Edition

3. The Washington Manual of Surgery, 6th Edition 2012

4. CHAPTER 5 : Fluids and Electrolyte Therapy in the Paediatric Surgical Patient by Mark W. Newton, Berouz Banieghbal, Kokila Lakhoo