Crystalloids

Listen to Audio

-aqueous solution
-low molecular weight salts
-with/without glucose
-rapidly equilibrate with the extracellular fluid compartment
-distributes throughout the extracellular fluid compartment
-glucose is often added to prevent ketosis and hypoglycemia
-D5W is used for replacements of pure water deficits and maintenance for sodium restriction
-hypertonic 3% saline used to correct symptomatic hyponatremia
-most common crystalloid solution intraoperatively is lactated ringers solution
ex.lactated ringers solution
-slightly hypotonic
-close to 100 ml free water / L
-commonly lowering serum [Na+] to 130 mEq/L
-lactate is converted into bicarbonate by liver metabolism
ex. large volumes of normal saline infusion
-may produce dilutional hyperchloremic acidosis

maintenance- type solutions: hypotonic , replace losses primarily due to water loss
replacement-type solutions : isotonic , replace losses from both water and electrolyte loss. Often used intraoperatively