Editing Intravenous therapy (section)

====Fluid solutions====
{{Main|Volume expander|Buffer solution}}
Fluids may be administered as part of "volume expansion", or fluid replacement, through the intravenous route. Volume expansion consists of the administration of fluid-based solutions or suspensions designed to target specific areas of the body which need more water. There are two main types of volume expander: [[crystalloids]] and [[colloid]]s. Crystalloids are [[aqueous solution]]s of mineral salts or other water-soluble molecules. Colloids contain larger insoluble molecules, such as [[gelatin]]. [[Blood]] itself is considered a colloid.<ref name="CCRP2020">{{cite journal |last1=Noonpradej |first1=Seechad |last2=Akaraborworn |first2=Osaree |title=Intravenous Fluid of Choice in Major Abdominal Surgery: A Systematic Review |journal=Critical Care Research and Practice |date=3 August 2020 |volume=2020 |pages=1–19 |doi=10.1155/2020/2170828|pmid=32832150 |pmc=7421038 |doi-access=free }}</ref>

The most commonly used crystalloid fluid is [[saline (medicine)|normal saline]], a solution of [[sodium chloride]] at 0.9% concentration, which is [[Isotonicity|isotonic]] with blood. Lactated Ringer's (also known as ''[[Ringer's lactate]]'') and the closely related ''Ringer's acetate'', are mildly [[hypotonic]] solutions often used in those who have significant [[burn]]s. Colloids preserve a high [[colloid osmotic pressure]] in the blood, while, on the other hand, this parameter is decreased by crystalloids due to hemodilution.<ref name="gregory">{{cite web |last1=Martin |first1=Gregory S. |title=An Update on Intravenous Fluids |url=http://www.medscape.com/viewarticle/503138 |website=Medscape |publisher=WebMD |access-date=25 August 2020}}</ref> Crystalloids generally are much cheaper than colloids.<ref name=gregory/>

[[Buffer solution]]s which are used to correct [[acidosis]] or [[alkalosis]] are also administered through intravenous access. [[Lactated Ringer's solution]] used as a fluid expander or base solution to which medications are added also has some buffering effect. Another solution administered intravenously as a buffering solution is [[intravenous sodium bicarbonate|sodium bicarbonate]].<ref>{{cite journal |last1=Fujii |first1=Tomoko |last2=Udy |first2=Andrew |last3=Licari |first3=Elisa |last4=Romero |first4=Lorena |last5=Bellomo |first5=Rinaldo |title=Sodium bicarbonate therapy for critically ill patients with metabolic acidosis: A scoping and a systematic review |journal=Journal of Critical Care |date=June 2019 |volume=51 |pages=184–191 |doi=10.1016/j.jcrc.2019.02.027|pmid=30852347 |s2cid=73725286 }}</ref>