CRNI Practice Exam 2026 – Complete Prep Guide

The osmolality range of an isotonic solution is typically 240 to 340 mOsm/L. Isotonic solutions have an osmolality that is similar to that of body fluids, primarily plasma, which generally has an osmolality of about 280 to 300 mOsm/L. This range is crucial as it helps maintain cell homeostasis; solutions within this range do not cause cells to swell (as in hypotonic solutions) or shrink (as in hypertonic solutions).

Understanding this range is essential for safe and effective intravenous therapy, as using solutions that are too hypotonic or hypertonic can lead to cellular imbalances, affecting a patient's overall health and treatment outcomes. The other ranges provided do not correspond to isotonic solutions; during infusion therapy, it's critical to select the right tonicity to match physiological conditions.