Water and Electrolyte Solutions

Selected Water and Electrolyte Solutions
Solution	Comments
Isotonic Solutions 0.9% NaCl (isotonic, also called NSS) Na+ 154 mEq/L Cl- 154 mEq/L (308 mOsm/L) Also available with varying concentrations of dextrose (the most frequent used is a 5% dextrose concentration	·   An isotonic solution that expands the ECF volume, used in hypovolemic states, resuscitative efforts, shock, diabetic ketoacidosis, metabolic alkalosis, hypercalcemia, mild Na deficit ·   Supplies an excess of Na and Cl; can cause fluid volume excess and hyperchloremic acidosis if used in excessive volumes, particularly in patients with compromised renal function, heart failure or edema ·   Not desirable as a routine maintenance solution, as it provides only Na and Cl (and these are provided in excessive amounts) ·   When mixed with 5% dextrose, the resulting solution becomes hypertonic in relation to plasma, and in addition to the above described electrolytes, provides 170cal/L ·   Only solution that may be administered with blood products
Lactated Ringer’s solution (Hartmann’s solution) Na+ 130 mEq/L K+ 4 mEq/L Ca++ 3 mEq/L Cl- 109 mEq/L Lactate (metabolized to bicarbonate) 28 mEq/L (274 mOsm/L) Also available with varying concentration of dextrose (the most common is 5% dextrose)	·   An isotonic solution that contains multiple electrolytes in roughly the same concentration as found in plasma (note that solution is lacking in Mg++) provides 9 cal/L ·   Used in the tx of hypovolemia, burns, fluid lost as bile or diarrhea, and for acute blood loss replacement ·   Lactate is rapidly metabolized into HCO3- in the body. Lactated Ringer’s solution should not be used in lactic acidosis because the ability to convert lactate into HCO3- is impaired in this disorder. ·   Not to be given with a pH > 7.5 because bicarbonates is formed as lactate breaks down causing alkalosis ·   Should not be used in renal failure because it contains potassium and can cause hyperkalemia ·   Similar to plasma

Selected Water and Electrolyte Solutions
Solution	Comments
Isotonic Solutions 5% Dextrose in Water (D5W) No electrolytes 50 g of glucose	·   An isotonic solution that supplies 170 cal/L and free water to aid in renal excretion of solutes ·   Used in treatment of hypernatremia, fluid loss and dehydration ·   Should not be used in excessive volumes in the early post-op period (when ADH secretion is increased due to stress reaction) ·   Should not be used solely in tx of fluid volume deficit, because it dilutes plasma electrolyte concentrations ·   Contraindicated in head injury because it may cause increased intracranial pressure ·   Should not be used for fluid resuscitation because it can cause hyperglycemia ·   Should be used with caution in patients with renal or cardiac dse because of risk of fluid overload ·   Electrolyte-free solutions may cause peripheral circulatory collapse, anuria in pt. with sodium deficiency and increased body fluid loss ·   Converts to hypotonic solution as dextrose is metabolized by body. Overtime D5W without NaCl can cause water intoxication (ICF vol. excess bec. solution is hypotonic)
Hypotonic Solutions 0.45% NaCl half-strength saline) Na+ 77 mEq/L Cl- 77 mEq/L (154 mOsm/L) Also available with varying concentration of dextrose (the most common is 5% dextrose)	·   Provides Na, Cl and free water ·   Free water is desirable to aid the kidneys in elimination of solute ·   Lacking in electrolytes other than Na and Cl ·   When mixed with 5% dextrose, the solution becomes slightly hypertonic to plasma and in addition to the above-described electrolytes provides 170 cal/L ·   Used in the tx of hypertonic dehydration, Na and Cl depletion and gastric fluid loss ·   Not indicated for third-space fluid shifts or increased intracranial pressure ·   Administer cautiously, because it can cause fluid shifts from vascular system into cells, resulting in cardiovascular collapse and increased intracranial pressure
Selected Water and Electrolyte Solutions
Solution	Comments
Hypertonic Solutions 3% NaCl (hypertonic saline) Na+ 513 mEq/L Cl- 513 mEq/L (1026 mOsm/L)	·   Used to increase ECF volume, decrease cellular swelling ·   Highly hypertonic solution used only in critical situations to treat hyponatremia ·   Must be administered slowly and cautiously, because it can cause intravascular volume overload and pulmonary edema ·   Supplies no calories ·   Assists in removing ICF excess
5% NaCl (hypertonic solution) Na+ 855 mEq/L Cl- 855 mEq/L (1710 mOsm/L)	·   Highly hypertonic solution used to treat symptomatic hyponatremia ·   Administered slowly and cautiously, because it can cause intravascular volume overload and pulmonary edema ·   Supplies no calories
Colloid Solutions Dextran in NS or 5% D5W Available in low-molecular-weight (Dextran 40) and high-molecular-weight (Dextran 70) forms	·   Colloid solution used as volume/plasma expander for intravascular part of ECF ·   Affects clotting by coating platelets and decreasing ability to clot ·   Remains in circulatory system up to 24 hours ·   Used to treat hypovolemia in early shock to increase pulse pressure, CO, and arterial BP ·   Improves microcirculation by decreasing RBC aggregation ·   Contraindicated in hemorrhage, thrombocytopenia, renal dse and severe dehydration ·   Not a substitute for blood or blood products