Intravenous Fluids

Crystalloids

Component (mEq/L) 0.9% NaCl Ringer's Lactate D5 1/2 NS 2/3 1/3
Sodium 154 130 77
Chloride 154 109 77
Potassium 4
Calcium 3
Lactate 28
Osmolarity (mOsm/L) 308 272

Saline versus Ringer's Lactate

A pair of recent trials examined NS vs RL/balanced crystalloids in both critically ill and non-critically ill adult patients:

  1. SALT-ED (2018)[^1]: Balanced crystalloids versus saline in noncritically ill adults.

    1. Population:
    2. Intervention:
    3. Comparator:
    4. Outcome:

  2. SMART (2018)[^2]: Balanced crystalloids versus saline in critically ill adults.

    1. Population:
    2. Intervention:
    3. Comparator:
    4. Outcome:

[^1]: Self WH, Semler MW, Wanderer JP, Wang L, Byrne DW, Collins SP, Slovis CM, Lindsell CJ, Ehrenfeld JM, Siew ED, Shaw AD. Balanced crystalloids versus saline in noncritically ill adults. New England Journal of Medicine. 2018 Mar 1;378(9):819-28. [^2]: Semler MW, Self WH, Wanderer JP, Ehrenfeld JM, Wang L, Byrne DW, Stollings JL, Kumar AB, Hughes CG, Hernandez A, Guillamondegui OD. Balanced crystalloids versus saline in critically ill adults. New England Journal of Medicine. 2018 Mar 1;378(9):829-39.

What crystalloid should be my pick?

In the absence of any major indications for normal saline, such as medication interactions, Ringer's Lactate should be the crystalloid of choice, especially if the patient is hyperchloremic. Theoretically in existing hyperkalemia, RL will equilibriate the serum potassium to 4 mmol/L. If renal kaliuresis is impaired then the potassium load may lead to accumulation.

Of note, the lactate in RL is sodium lactate, not lactic acid. It does not cause a lactic acidosis. Since it is a weak base (proton acceptor), it might actually buffer the pH a little (source need). Accumulation of the lactate may occur if the liver is unable to metabolize the lactate load. This may interfere with interpretation of lactate levels.

Discussion can be found here:

Colloids

Albumin

Starch

Crystalloids versus Colloids