Fluid and Electrolyte Acid-Base imbalance and its management: What is fluid and electrolyte imbalance? If the osmolarity of a solution is the same as the osmolarity of body fluid (300 mol/liter), then it is called an isotonic fluid. If the osmolarity of a fluid is greater than the body fluid osmolarity, it is called a hypertonic solution. If the osmolarity of a fluid is less than that of body fluid,