6 - Regulation of fluids and electrolytes

Abstract

Fluid and electrolyte disturbances are common in acutely ill children, and an understanding of renal physiology and management of electrolyte disturbances is central in the management of the perioperative child. Renal physiology is reviewed in detail, including glomerular filtration, the renin angiotensin system, and the role that antidiuretic hormone plays in sodium and water homeostasis. Fluid and electrolyte management is discussed as it relates to maintenance fluid therapy, treatment of volume depletion, perioperative fluid management, prevention of postoperative hyponatremia, and the administration of saline and how it might contribute to adverse renal outcomes in comparison to balanced solutions. The evaluation of hyponatremia is reviewed, particularly postoperative hyponatremia, the syndrome of inappropriate antidiuretic hormone secretion, and clinical manifestation and treatment of hyponatremic encephalopathy. Electrolyte disturbances are discussed regarding potassium, calcium, magnesium, and phosphorus, and the use of diuretics.