Isolyte S

Isolyte® S is a balanced crystalloid solution created by B. Braun Medical Inc. As a cardiothoracic anesthesiologist and intensivist, it’s the crystalloid I use the most in the perioperative and ICU settings. Compared to lactated Ringers, here are the constituents of the two fluids:

Isolyte SLactated Ringers
Sodium (mEq/L)141130
Potassium (mEq/L)54
Chloride (mEq/L)98109
Calcium (mEq/L)3
Magnesium (mEq/L)3
Lactate (mEq/L)28
Gluconate (mEq/L)23
Acetate (mEq/L)27
Osmolarity (mOsm/L)295273
Isolyte S

Although I prefer Isolyte S, I’ll take any balanced crystalloid solution over normal saline! 🙂

Drop me a comment below with questions!

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  1. What is your reasoning for your preference for plasmalyte over LR? I’ve worked with attendings who feel strongly about this too but haven’t been able to find any study comparing the two, I’ve only seen studies comparing one or the other to NS. Thanks in advance!

    1. I’m not aware of any studies comparing Isolyte/PlasmaLyte to LR head-to-head. I just feel Isolyte/PlasmaLyte is more physiologic (based on pH, osmolarity, etc.)

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