Intravenous Fluids: Composition and Indications

Abstract

This chapter reviews various fluids available for intravenous (IV) administration. The IV fluids can be broadly divided into two categories: crystalloids and colloids. Crystalloid solutions contain water, electrolytes, and/or glucose, whereas colloids include mostly albumin and blood products. IV solutions can be isotonic, hypotonic, or hypertonic. In general, isotonic solutions are used to treat extracellular fluid (ECF) volume depletion, hypotonic solutions to replace ECF and intracellular fluid (ICF) water loss, and hypertonic solutions to correct symptomatic hyponatremia. Hypertonic saline is often used in trauma settings because it decreases the intracranial pressure in patients with head trauma and for patients following burns. It is important to know the composition of commonly used crystalloids and colloids before we understand their indications.