|Intravenous Fluids, Components, and Compatibility |
Often, patients need only small amounts of IV fluids to keep a vein open for intermittent medication administration, for blood administration, or for diagnostic procedures. However, a patient who suffers a fluid loss that cannot adequately be replaced by oral fluids will need IV fluid to restore and then maintain the body’s fluid balance. An IV fluid solution is selected for its concentration, or osmolarity, which affects the body’s intracellular fluid (ICF) and extracellular fluid (ECF). ICF and ECF, also referred to as serum, normally have the same osmolarity of approximately 300 milliosmoles/liter [mOsm/l]. Patients who are overloaded with fluids have a lower serum osmolarity, and patients who are dehydrated have a higher serum osmolarity.
IV solutions are labeled with the name and exact amount of all components in the solution. Solutions contain different concentrations of dextrose (glucose) or sodium chloride (NaCl) (Figure 4-1). For example, a solution of 5% dextrose contains 5 g of dextrose per 100 mL. Normal saline (NS) is 0.9% NaCl; it contains 900 mg, or 0.9 g, of sodium chloride per 100 mL. In turn, 0.45% NaCl, or ½ NS, has 450 mg of sodium chloride per 100 mL. Other sodium chloride concentrations include 0.3% NaCl (1⁄3 NS), with 300 mg of sodium chloride, and 0.225% NaCl (¼ NS), with 225 mg of sodium chloride.