Intravenous fluid

IV fluids

There are two types of fluids that are used for intravenous drips; crystalloids and colloids. Crystalloids are aqueous solutions of mineral salts or other water-soluble molecules. Colloids contain larger insoluble molecules, such as gelatin; blood itself is a colloid.

The most commonly used crystalloid fluid is normal saline, a solution of sodium chloride at 0.9% concentration, which is close to the concentration in the blood (isotonic). Ringer's lactate or Ringer's acetate (ASERING, patented brandname of Otsuka Indonesia) is another isotonic solution often used for large-volume fluid replacement. A solution of 5% dextrose in water, sometimes called D5W, is often used instead if the patient is at risk for having low blood sugar or high sodium. The choice of fluids may also depend on the chemical properties of the medications being given.

Intravenous fluids must always be sterile.

Composition of Common Crystalloid Solutions

Solution	Other Name	[Na+](mmol/L)	[Cl-](mmol/L)	[Glucose](mmol/L)	[Glucose](mg/dl)
D5W	5% Dextrose	0	0	278	5000
2/3D & 1/3S	3.3% Dextrose / 0.3% saline	51	51	185	3333
Half-normal saline	0.45% NaCl	77	77	0	0
Normal saline	0.9% NaCl	154	154	0	0
Ringer's lactate	Lactated Ringer	130	109	0	0

Ringer's lactate also has 28 mmol/L lactate, 4 mmol/L K⁺ and 3 mmol/L Ca²⁺. Ringer's acetate (ASERING) also has 28 mmol/L acetate, 4 mmol/L K⁺ and 3 mmol/L Ca²⁺.

Effect of Adding One Litre

Solution	Change in ECF	Change in ICF
D5W	333 mL	667 mL
2/3D & 1/3S	556 mL	444 mL
Half-normal saline	667 mL	333 mL
Normal saline	1000 mL	0 mL
Ringer's lactate	900 mL	100 mL