IV Fluids and Solutions Guide & Cheat Sheet

This guide breaks down the intravenous solutions you will hang on the floor: how to tell isotonic, hypotonic, and hypertonic IV fluids apart, and the nursing management for each.

What are IV Fluids?

IV fluids (intravenous solutions) are supplemental fluids used to restore or maintain fluid volume and electrolyte balance when the oral route is not possible. They deliver fluids straight into the intravascular compartment, replace electrolyte losses, and carry medications and blood products.

Types of IV Fluids

The most common way to categorize IV fluids is by tonicity:

• Isotonic. Same concentration of solutes as blood plasma.
• Hypotonic. Lower solute concentration than plasma.
• Hypertonic. Higher solute concentration than plasma.

They can also be classified by purpose:

• Nutrient solutions may contain dextrose, glucose, and levulose plus water. Water covers fluid requirements, carbohydrate supplies calories, and the solution helps prevent dehydration and ketosis. Examples: D5W, D5NSS.
• Electrolyte solutions carry cations and anions to replace fluid and electrolytes in clients with continuing losses. Examples: 0.9 NaCl, Ringer's Solution, LRS.
• Alkalinizing solutions treat metabolic acidosis. Example: LRS.
• Acidifying solutions counteract metabolic alkalosis. Examples: D51/2NS, 0.9 NaCl.
• Volume expanders increase blood volume after severe blood or plasma loss. Examples: dextran, human albumin, plasma.

Crystalloids

Crystalloid IV solutions contain small molecules that flow easily across semipermeable membranes, categorized by tonicity relative to plasma: isotonic, hypotonic, and hypertonic.

Isotonic IV Fluids

Most IV fluids are isotonic, with the same solute concentration as blood plasma. Infused, they expand intracellular and extracellular fluid spaces equally and do not alter the osmolality of the vascular compartment. Electrolyte solutions are considered isotonic if total electrolyte content is approximately 310 mEq/L. Their total osmolality is close to that of the ECF, so they do not shrink or swell red blood cells.

0.9% NaCl (Normal Saline Solution, NSS)

Normal saline solution (0.9% NaCl) is a crystalloid isotonic IV fluid containing water, sodium (154 mEq/L), and chloride (154 mEq/L), with an osmolality of 308 mOsm/L and no calories. It is called normal saline because its sodium chloride percentage matches the usual concentration of sodium and chloride in the intravascular space. It is the isotonic solution of choice for expanding extracellular fluid (ECF) volume because it does not enter the intracellular fluid (ICF), and it corrects ECF volume deficit by staying in the ECF.

Normal saline is the IV fluid used alongside blood products, and it replaces large sodium losses as in burns and trauma. Do not use it in heart failure, pulmonary edema, renal impairment, or conditions causing sodium retention, since it risks fluid volume overload.

Dextrose 5% in Water (D5W)

D5W is a crystalloid isotonic IV fluid with a serum osmolality of 252 mOsm/L. It starts isotonic and provides free water as dextrose is metabolized (becoming hypotonic), expanding both ECF and ICF. It supplies water and corrects increased serum osmolality. A liter provides fewer than 200 kcal and contains 50g of glucose. Do not use it for fluid resuscitation, since hyperglycemia can result, and avoid it in clients at risk for increased intracranial pressure, as it can cause cerebral edema.

Lactated Ringer's 5% Dextrose in Water (D5LRS)

Lactated Ringer's Solution (Ringer's Lactate or Hartmann solution) is a crystalloid isotonic IV fluid built to be a near-physiological balanced electrolyte solution. It contains 130 mEq/L sodium, 4 mEq/L potassium, 3 mEq/L calcium, and 109 mEq/L chloride, plus bicarbonate precursors to prevent acidosis. It provides no calories or magnesium and limited potassium replacement. Its electrolyte content most closely matches blood serum and plasma, making it the most physiologically adaptable fluid.

Lactated Ringer's corrects dehydration and sodium depletion and replaces GI fluid losses, including losses from burns, fistula drainage, and trauma. It is a first-line resuscitation choice for certain patients and is often given in metabolic acidosis.

It is metabolized in the liver, which converts the lactate to bicarbonate, so do not give it to patients who cannot metabolize lactate (e.g., liver disease, lactic acidosis). Use caution in heart failure and renal failure.

Ringer's Solution

Ringer's solution is isotonic with content similar to Lactated Ringer's but without lactate. Indications are the same, without the lactate-related contraindications.

Nursing Considerations for Isotonic IV Solutions

• Document baseline data. Assess vital signs, edema status, lung sounds, and heart sounds before infusion, and keep monitoring during and after.
• Watch for fluid overload. Look for hypervolemia: hypertension, bounding pulse, pulmonary crackles, dyspnea, shortness of breath, peripheral edema, jugular venous distention, and extra heart sounds.
• Watch for continued hypovolemia: decreased urine output, poor skin turgor, tachycardia, weak pulse, hypotension.
• Prevent hypervolemia. Patients treated for hypovolemia can quickly become overloaded with rapid or over-infusion.
• Elevate the head of the bed 35 to 45 degrees (semi-Fowler's) unless contraindicated.
• Elevate the legs if edema is present, to promote venous return.
• Educate patients and families to recognize fluid overload and to report trouble breathing or swelling.
• Monitor heart failure patients closely, since isotonic fluids expand the intravascular space.

Hypotonic IV Fluids

Hypotonic IV solutions have lower osmolality and fewer solutes than plasma. They shift fluid from the ECF into the ICF for homeostasis, causing cells to swell and possibly rupture. A solution is hypotonic if total electrolyte content is less than 250 mEq/L. These provide free water for excreting body wastes, treat cellular dehydration, and replace cellular fluid.

0.45% Sodium Chloride (0.45% NaCl)

Sodium chloride 0.45% (1/2 NS), or half-strength normal saline, is hypotonic and replaces water in patients with hypovolemia plus hypernatremia. Excess use can cause hyponatremia from sodium dilution, especially in patients prone to water retention. It has an osmolality of 154 mOsm/L and contains 77 mEq/L sodium and chloride. Hypotonic sodium solutions treat hypernatremia and other hyperosmolar conditions.

0.33% Sodium Chloride (0.33% NaCl)

0.33% Sodium Chloride lets the kidneys retain needed water and is typically given with dextrose to increase tonicity. Use caution in heart failure and renal insufficiency.

0.225% Sodium Chloride (0.225% NaCl)

0.225% Sodium Chloride is often a maintenance fluid for pediatric patients, the most hypotonic IV fluid available at 77 mOsm/L. Used with dextrose.

2.5% Dextrose in Water (D2.5W)

D2.5W is hypotonic, used to treat dehydration and low sodium and potassium levels. Do not give it with blood products, as it can cause hemolysis of red blood cells.

Nursing Considerations for Hypotonic IV Solutions

• Document baseline data (vital signs, edema, lung and heart sounds) before, during, and after infusion.
• Do not use in contraindicated conditions. Hypotonic solutions can worsen hypovolemia and hypotension and cause cardiovascular collapse. Avoid in liver disease, trauma, or burns.
• Risk for increased intracranial pressure (IICP). Do not give to patients at risk, since the fluid shift can cause cerebral edema (hypotonic solutions make cells swell).
• Monitor for fluid volume deficit, including confusion in older adults. Tell patients to report dizziness.
• Excessive infusion can cause intravascular fluid depletion, decreased blood pressure, cellular edema, and cell damage.
• Do not give with blood products, since most hypotonic solutions can hemolyze red blood cells, especially during rapid infusion.

Hypertonic IV Fluids

Hypertonic IV solutions have a greater solute concentration (375 mEq/L and greater) than plasma and move fluid out of cells into the ECF to balance particle concentration between compartments. Cells shrink, which can disrupt function. They are also called volume expanders, drawing water out of the intracellular space to increase extracellular volume.

Hypertonic Sodium Chloride IV Fluids

These contain more sodium and chloride than plasma, shifting fluids from the intracellular space into the intravascular and interstitial spaces. Available forms and strengths:

• 3% sodium chloride (3% NaCl): 513 mEq/L sodium and chloride, osmolality 1030 mOsm/L.
• 5% sodium chloride (5% NaCl): 855 mEq/L sodium and chloride, osmolality 1710 mOsm/L.

These treat acute sodium deficiency (severe hyponatremia) and should be used only in critical situations. Infuse at a very low rate to avoid overload and pulmonary edema. Given in large quantities and rapidly, they can cause extracellular volume excess and precipitate circulatory overload and dehydration, so administer cautiously and usually only once serum osmolality has dropped to critically low levels. Some patients need diuretic therapy to assist fluid excretion. Also used in cerebral edema.

Hypertonic Dextrose Solutions

Isotonic solutions containing 5% dextrose (e.g., D5NSS, D5LRS) are slightly hypertonic because they exceed the total osmolality of the ECF, but dextrose is quickly metabolized and only the isotonic solution remains, so the effect on the ICF is temporary. Hypertonic dextrose solutions provide short-term kilocalories. Higher concentrations (D50W) are strongly hypertonic and must go into central veins to be diluted by rapid blood flow.

Dextrose 10% in Water (D10W)

D10W is hypertonic, used for ketosis of starvation, providing calories (380 kcal/L), free water, and no electrolytes. Give via a central line if possible, and not on the same line as blood products, since it can cause RBC hemolysis.

Dextrose 20% in Water (D20W)

D20W is a hypertonic IV solution and osmotic diuretic that shifts fluid between compartments to promote diuresis.

Dextrose 50% in Water (D50W)

D50W is hypertonic, used to treat severe hypoglycemia, administered rapidly via IV bolus.

Nursing Considerations for Hypertonic IV Fluids

• Document baseline data (vital signs, edema, lung and heart sounds) before, during, and after infusion.
• Watch for hypervolemia. Since hypertonic solutions move fluid from ICF to ECF, they raise extracellular volume and overload risk. Look for swelling in arms, legs, and face, shortness of breath, high blood pressure, and discomfort (headache, cramping).
• Observe constantly during administration. Give only in high-acuity areas with constant nursing surveillance.
• Verify the order, which should state the specific fluid, total volume, infusion rate, and length of infusion.
• Assess health history. Do not give to patients with kidney or heart disease or dehydration, as these solutions affect renal filtration and easily cause hypervolemia in renal or cardiac patients.
• Prevent fluid overload.
• Do not give peripherally. Hypertonic solutions irritate and damage vessels and must go through a central vascular access device in a central vein.
• Monitor blood glucose closely. Rapid infusion of hypertonic dextrose can cause hyperglycemia. Use caution in diabetes mellitus.

Colloids

Colloids contain large, high-molecular-weight molecules that do not pass through semipermeable membranes. They are technically hypertonic and, when infused, exert an osmotic pull of fluids from interstitial and extracellular spaces, expanding intravascular volume and raising blood pressure. Indicated for malnourished patients and those who cannot tolerate large fluid infusions.

Human Albumin

Human albumin is derived from plasma in two strengths: 5% albumin and 25% albumin. 5% albumin is a common colloid used to increase circulating volume and restore protein levels in burns, pancreatitis, and plasma loss from trauma. 25% albumin is used with sodium and water restriction to reduce excessive edema. Both are considered blood transfusion products and follow the same protocols and precautions.

Albumin is contraindicated in severe anemia, heart failure, or known sensitivity to albumin. Withhold angiotensin-converting enzyme inhibitors for at least 24 hours before giving albumin, because of the risk of atypical reactions like hypotension and flushing.

Dextrans

Dextrans are polysaccharides that act as colloids, available as low-molecular-weight dextrans (LMWD) and high-molecular-weight dextrans (HMWD), in saline or glucose solutions. Dextran interferes with blood crossmatching, so draw the patient's blood before administering it if crossmatching is anticipated.

Low-Molecular-Weight Dextrans (LMWD)

LMWD contains polysaccharide molecules with an average molecular weight of 40,000 (Dextran 40). It improves microcirculation in patients with poor peripheral circulation, contains no electrolytes, and treats shock from vascular volume loss (burns, hemorrhage, trauma, surgery). In some surgical procedures it is used to prevent venous thromboembolism. Contraindicated in thrombocytopenia, hypofibrinogenemia, and dextran hypersensitivity.

High-Molecular-Weight Dextrans (HMWD)

HMWD contains polysaccharide molecules with an average molecular weight of 70,000 (Dextran 70) or 75,000 (Dextran 75), used for hypovolemia and hypotension. Contraindicated in hemorrhagic shock.

Etherified Starch

Derived from starch and used to increase intravascular fluid, but can interfere with normal coagulation. Examples: EloHAES, HyperHAES, Voluven.

Gelatin

Gelatins have a lower molecular weight than dextrans and stay in circulation for a shorter time.

Plasma Protein Fraction (PPF)

Plasma Protein Fraction is prepared from plasma and, like albumin, is heated before infusion. Infuse slowly to increase circulating volume.

Nursing Considerations for Colloid IV Solutions

• Assess allergy history. Colloids can cause allergic reactions, though rarely; ask specifically about prior reactions to IV infusions.
• Use a large-bore needle (18-gauge).
• Document baseline data (vital signs, edema, lung and heart sounds) before, during, and after infusion.
• Monitor the response. Track intake and output for hypervolemia, hypertension, dyspnea, crackles, and edema.
• Monitor coagulation indexes, since colloids can interfere with platelet function and increase bleeding times.