Definition: A condition that occurs when output of body fluids exceeds fluid intake.
Pathophysiology: In early dehydration, fluid loss is from both intracellular and extracellular compartments. In chronic dehydration, fluid loss is predominantly cellular. Fluid loss may result in shock, acidosis or alkalosis, kidney and brain damage in children; death occurs much more quickly than in the adult patient.
Etiology: Usual causes are diarrhea, vomiting, extensive burns, or diabetic ketoacidosis.
Manifestations: Poor skin turgor or “tenting” when skin over sternum is lifted by examiner, dry mouth, lack of tears in child over 3 months old, sunken anterior fontanel if fontanel has not closed, weight loss, decreased urine output, and urine specific gravity over 1.023. Decreased blood pressure is not an early, but a late, sign of shock in children because their blood vessels adapt quickly to intravascular fluid loss.
Med Treatment: Oral rehydration fluids (ORS) if patient can ingest and retain fluids. IV fluids and electrolytes if patient cannot ingest or retain fluids. For children IV fluids for the first 8 hours include maintenance amount plus 1/2 the estimated fluid deficit (using 1 kg of weight loss to represent 1000 mL of fluid loss) administered in the first 8 hours and the remaining 1/2 of estimated deficit added to maintenance fluid administered in the next 24 to 48 hours. Excessive ongoing losses determined by strict I&O must also be factored in calculation. Goal is to achieve 0.5 to 1 mL/h urinary output for each kilogram of body weight and to diagnose and treat underlying cause of dehydration.
Nursing Diagnosis: Fluid volume deficit, altered tissue perfusion.
Nursing Care: Maintain strict I&O. For babies, subtract weight of dry diaper from weight of wet diaper using 1 g of weight to represent 1 mL of output. (Count both urine and liquid stools as fluid output.) Continue to assess for degree of dehydration or overhydration. Calculate appropriateness of ordered IV fluids. Warning: Avoid IV fluids containing potassium until the patient has voided.
Prognosis: Excellent when fluids and electrolytes are replaced appropriately. Warning: Children become dehydrated and overhydrated much more quickly than adults.