Pediatric Intravenous Fluid Therapy

Maintenance intravenous fluids (IVFs) are used to provide critical supportive care for children

who are acutely ill. IVFs are required if sufficient fluids cannot be provided by using enteral administration for reasons such as gastrointestinal illness, respiratory compromise, neurologic impairment, a perioperative state, or being moribund from an acute or chronic illness. In defining appropriate maintenance IVFs it should include the composition of IVF needed to preserve a child’s extracellular volume while simultaneously minimizing the risk of developing volume depletion, fluid overload, or electrolyte disturbances, such as hyponatremia or hypernatremia.

Because maintenance IVFs may have both potential benefits and harms, they should only be

administered when clinically indicated. The administration of hypotonic IVF has been the standard in pediatrics. Concerns have been raised that this approach results in a high incidence of hyponatremia and that isotonic IVF could prevent the development of hyponatremia. Guidelines for maintenance IVF therapy in children have primarily been opinion based, and evidence-based consensus guidelines are lacking.(1)

The goal of fluid therapy is to preserve the normal body water volume and its electrolyte composition (2)

● Maintenance therapy replaces the ongoing daily losses of water and electrolytes occurring

via physiologic processes (urine, sweat, respiration, and stool), which normally preserve homeostasis. Maintenance requirements vary depending on the patient's underlying clinical status and setting, especially in postoperative or hospitalized children, due to changes in their physiologic responses (eg, excess antidiuretic hormone [ADH] secretion).

● Repletion therapy corrects water and acute electrolyte deficits that have accrued via illness or physiologic abnormality. Repletion returns the patient to a normal volume and electrolyte status.

Emergency and Critical care provision are aimed at maintaining ‘homeostasis’ in the body which is vital for the organ’s support and optimal function. This involves not only fluids but also electrolytes balance. Electrolyte imbalances are common in pediatric patients.(3)

Five possible mechanisms for the occurrence of electrolyte imbalance are:

• Underlying disease process,

• End organ injury,

• Fluid & electrolyte interventions,

• Use of medications with potential electrolyte derangements

• Application of critical care technology i.e. positive pressure ventilation.(4)

The higher and lower value of critical electrolytes like sodium, potassium and chloride can affect

cellular processes drastically as it may result in cardiac and neurological complications.(5).

Delayed correction and prolonged electrolyte imbalances alter the patient`s status in terms of morbidity and mortality. Electrolyte imbalance significantly affects the quality of life of the patient.(6) These imbalances also result in longer stay in hospitals thus adding significantly to the costs of management.(7) Thus early recognition and intervention to correct these imbalances is essential to avoid poor outcome.(8)

Hypernatremia is defined as a serum sodium concentration of more than 145 mEq/L. It is characterized by a deficit of total body water (TBW) relative to total body sodium levels due to either loss of free water; infrequently, the administration of hypertonic sodium solutions .(9)

Neurologic complications related to hypernatremia occur in 15% of patients. The neurologic sequelae consist of intellectual deficits, seizure disorders, and spastic plegias. In children with acute hypernatremia, mortality rates are as high as 20 %.(10)

Hyponatremia is defined as a plasma sodium concentration of less than 135 mEq/L .(11) Acute, severe hyponatremia that develops within 48 hours may develop acute cerebral edema and various sequelae, such as headache, lethargy, seizures, and cardiac arrest due to brain stem herniation.(12) Recent evidence suggests that even mild chronic hyponatremia sequelae can be associated with subtle neurologic defects, such as impairments in balance and attention that can increase the incidence of falls.(13)

Potassium is the second most abundant cation in the body. About 98% of potassium is intracellular, particularly in skeletal muscle, where the concentration ranges from 140 to 150 mEq/L. Only about 2% of the body’s potassium is in the extracellular fluid, where the concentration is tightly regulated at 3.5 to 5.5 mEq/L.(14)

Hyperkalemia is defined as a serum potassium concentration of > 5.5 mEq/L, it is moderate (6 to

7 mEq/L) and severe (> 7 mEq/L). Clinical manifestations of hyperkalemia include weakness, confusion, and muscular or respiratory paralysis. Early electrocardiographic (ECG) changes seen with hyperkalemia and may ultimately progress to complete heart block, Ventricular arrhythmias or cardiac arrest may ensue if no effort is made to lower the serum potassium level.(15)

Hypokalemia is defined as serum potassium level less than 3.6 mEq/L occurs in up to 21% of hospitalized patients.(16) Hypokalemia is often asymptomatic. But some warning signs should be cautiously evaluated which include weakness or palpitations or changes on ECG.(17)