Editing IV fluids


== Crystalloids ==

* Electrolyte solutions with small molecules that can diffuse freely from intravascular to interstitial fluid compartments
* 25% will stay intravascularly, and 75% will be in the interstitial compartment
* 0.9% saline
** Differs from plasma - higher sodium and chloride concentrations, higher osmolality, lower pH
** Cause interstitial oedema more than CSL due to higher sodium load
** Produces a hyperchloraemic metabolic acidosis in large volumes
* Ringer's lactate (CSL/Hartmann's)
** Essentially 0.9% NaCL with sodium lactate, potassium and ionised calcium added
** Doesn't change pH
** Doesn't change serum lactate in healthy patients, and the impact on unwell patients is unknown, but is thought to be negligible, unless the bloods are taken from downstream
* 5% dextrose
** Does provide some calories - 3L = 510kcal/day, although this is less important now that we have TPN and enteral feeding
** Causes a disproportionate cellular swelling due to uptake of dextrose; conversely, causes cellular dehydration in patients with impaired cellular glucose uptake
** Encourages anaerobic metabolism in critically unwell patients - causes a significant rise in serum lactate
** Causes hyperglycaemia
** Therefore, don't use it for critically ill patients

== Colloid fluids ==

* A particulate solution with particles that do not dissolve completely. In clinical terms, this is a fluid with solutes that cannot pass into the interstitium, and hence create a colloid osmotic pressure/oncotic pressure to hold water in the vascular compartment.
* Albumin solutions
** Usually given as 250mL of 5%, or 50-100mL of 25%
** Volume effect begins to dissipate at 6 hours, and can be lost after 12 hours
** 5% is safe to use as a resuscitation fluid, and may outperform crystalloids where hypovolaemia is secondary to blood loss (although, should just give blood)
** The 25% solution draws fluid intravascularly from interstitial space, and therefore shouldn't be used for volume resuscitation, but may be useful in situations where hypovolaemia is the result of hypoalbuminaemia


[[Category:Peri-op medicine]]
[[Category:Intern education]]