MS 7

IV Therapy: Definition & General Principles

• IV therapy = administration of fluids or medications directly into the bloodstream via a needle or catheter (a.k.a. cannula).

• Provides immediate systemic effects because it bypasses the gastrointestinal tract and first-pass hepatic metabolism.

• Scope of practice (NCLEX-PN® link):

  • Maintain & discontinue peripheral IV catheters.

  • Maintain central venous catheters.

• Core clinical goals: rapid hydration, electrolyte management, nutrition, medication delivery, and blood component transfusion.

Indications for IV Therapy

• Hydration when oral intake is insufficient or impossible.

• Electrolyte replacement (e.g., \text{K}^+, \text{Mg}^{2+}, \text{Ca}^{2+}).

• Parenteral nutrition (PN)
  • Peripheral PN (PPN) for short-term, lower osmolarity formulas.
  • Central PN (TPN) for hypertonic, long-term needs.

• Medication administration (antibiotics, analgesics, vasoactive drugs, etc.).

• Blood product transfusions (RBCs, platelets, plasma, cryoprecipitate).

Types of IV Infusions

• Continuous: fluid runs non-stop at a programmed rate.

• Intermittent:
  • Secondary or "piggyback" — small IV bag connected above primary line.

• Direct injection / IV push: medication administered over seconds–minutes into the port.

• Patient-controlled analgesia (PCA): micro-boluses delivered via programmable pump that the patient activates.

Methods of Administration

• Gravity drip: height of bag provides pressure; rate set with roller clamp.

• Electronic infusion devices (EIDs): smart pumps that calculate & maintain mL/hr, dose/kg/min, alarms for errors.

• Mechanical controllers: use spring or diaphragm to regulate flow without electronics.

Factors Affecting Flow Rate

• Cannula position changes (e.g., arm flexion occludes flow).

• Height of solution — each 12 in (30 cm) ≈ \uparrow pressure by \approx 22 \text{ mmHg}.

• Patency of cannula (clots, precipitate, fibrin).

• Vein condition (spasm, tortuosity, valve obstruction).

• Kinks or dependent loops in tubing; closed roller clamp.

IV Fluids Classification (by content)

• Dextrose solutions (D5W, D10W, etc.).

• Sodium chloride solutions (NS 0.9 %, 0.45 %, 0.33 %).

• Combined dextrose & sodium chloride (D5NS, D5½NS).

• Ringer’s & Lactated Ringer’s (LR) — contain \text{Na}^+, \text{K}^+, \text{Ca}^{2+}, \text{Cl}^- ± lactate (buffer).

• Balanced electrolyte solutions (e.g., Plasma-Lyte).

Osmolarity & Tonicity

• Osmolarity = ionic concentration of solute per litre of solvent; body plasma ≈ 275–295\, \text{mOsm/L}.

• Isotonic Solutions: “I So Perfect – Cells Stay the Same”

  In an isotonic solution, the concentration of solutes is equal inside and outside the cell. Because of this balance, there is no net movement of water in or out of the cell. Water enters and exits at the same rate, so the cell maintains its normal shape and size. These solutions are commonly used in clinical settings to maintain fluid balance or to treat fluid loss without changing the size of the cells. Examples include 0.9% Normal Saline (NS), Lactated Ringer’s (LR), and D5W (only initially, before the sugar is metabolized). Nurses use isotonic fluids for blood loss, dehydration, and general fluid resuscitation.

  🧠 Memory trick: Think “ISO = I So Perfect” or “I So Tonic = I So Stable,” meaning cells stay the same size.

  Hypotonic Solutions: “Hippo-tonic – Cell Swells Like a Hippo”

  A hypotonic solution has a lower solute concentration outside the cell than inside. This causes water to move into the cell, trying to dilute the more concentrated interior. As a result, the cell swells and can even burst in extreme cases. This type of solution is useful when treating cellular dehydration, such as in patients with diabetic ketoacidosis (DKA) or hyperosmolar hyperglycemic syndrome (HHS). Examples of hypotonic fluids include 0.45% Normal Saline (½ NS) and D5W after metabolism (when the dextrose is absorbed and only free water remains). However, hypotonic solutions should not be given to patients with increased intracranial pressure (ICP), burns, or trauma, as they can cause or worsen brain swelling.

  🧠 Memory trick: “HYPO = HIPPO” — cells get big and fat like a hippo.

  Hypertonic Solutions: “Hyper Shrinks – Cells Shrivel Up”

  In a hypertonic solution, the solute concentration is higher outside the cell than inside. This pulls water out of the cell, causing it to shrink or crenate. Hypertonic solutions are helpful for drawing fluid out of swollen tissues or cells, such as in cases of hyponatremia or cerebral edema. Common hypertonic fluids include 3% Normal Saline, D5NS, D5½NS, D10W, and TPN (Total Parenteral Nutrition). Because these solutions shift fluid out of the cells into the bloodstream, nurses must monitor for signs of fluid overload, such as crackles in the lungs or pulmonary edema. Strong hypertonic solutions (e.g., 3% NS) are often administered through a central line due to their high concentration.

  🧠 Memory trick: Think “HYPER = Runner = Cell SHRINKS” — cells lose water and get skinny.

Vascular Access Routes

• Peripheral IV: short catheter (≤ 3 in) into superficial veins of hand/forearm (cephalic, basilic, metacarpal, dorsal arch).
  • Needleless connectors increase safety.

• Central Venous Access Devices (CVADs): tip resides in superior vena cava or right atrium. Types:
  • Non-tunneled central catheter — inserted through subclavian or internal jugular; short-term.
  • Tunneled catheter (e.g., Hickman, Broviac) — subcutaneous tunnel with Dacron cuff; long-term.
  • Peripherally inserted central catheter (PICC) — inserted into basilic/cephalic, advanced to SVC.
  • Implanted vascular port (Medi-Port) — reservoir under skin; accessed with non-coring (Huber) needle.

• Rationale: PN, chemo, vesicant drugs, frequent blood draws, long-term therapy.

Nursing Diagnoses (Common)

• Risk for Fluid Volume Excess.

• Impaired Physical Mobility (tubing, pumps, pole limitations).

• Risk for Infection (break in skin & direct bloodstream route).

Gerontological Considerations

• Older adults have ↓cardiac & renal reserve → monitor closely for overload:
  • ↑BP, bounding pulse, jugular venous distention (JVD).
  • Rapid, shallow respirations; crackles.
  • Sudden weight gain, pitting edema, ↑urine output (early) then ↓ (late).

Complications of IV Therapy

Local

• Hematoma: blood leaks into tissue at site (bruising, swelling).

• Thrombosis: clot inside cannula or vein → resistance to flush.

• Phlebitis / Thrombophlebitis: inflammation (erythema, pain, warmth, cord-like vein).

• Infiltration: non-vesicant fluid leaks into tissue (cool, pale, edema).

• Extravasation: vesicant leaks → tissue necrosis (pain, blistering).

• Local infection: purulent drainage, redness.

• Venous spasm: sudden sharp pain, slowed flow.

• Nerve injury: tingling, numbness, shooting pain during insertion.

Systemic

• Septicemia: pathogens enter bloodstream (fever, chills, hypotension).

• Circulatory overload: excess volume → pulmonary edema.

• Venous air embolism: air bolus obstructs pulmonary circulation (dyspnea, chest pain, mill-wheel murmur).

• Speed shock: rapid infusion → toxic drug levels (flushing, headache, chest tightness, LOC changes).

Parenteral Nutrition (PN)

• Components per provider prescription:
  • Carbohydrate: dextrose (main caloric source; conc. typically 5–70 %).
  • Protein: amino acid solutions.
  • Lipids: 10 % or 20 % emulsions; may be piggybacked or mixed (3-in-1).
  • Electrolytes: \text{Na}^+, \text{K}^+, \text{Mg}^{2+}, \text{Ca}^{2+}, \text{Cl}^-.
  • Trace elements & vitamins.

• Indications: unable to eat or absorb, pre-op weight optimisation, malnutrition, wound healing, cancer cachexia.

Nursing Care for PN

• Initiate slowly (prevent hyperglycemia & fluid shifts).

• Monitor blood glucose at least every 4–6 hr; sliding-scale insulin may be required.

• Daily weight & strict intake/output.

• Assess for infection (dressing, catheter hub, systemic signs).

• If PN bag empties & next bag unavailable: hang 10 % dextrose to prevent hypoglycemia.

Home & Alternative Infusion Therapies

• Home IV: hydration, antibiotics, PN, analgesia; requires patient/caregiver teaching & supply delivery.

• Subcutaneous infusion (Hypodermoclysis):
  • Isotonic solutions only (0.9 % NaCl, D5W) + limited meds.
  • Advantages: slow absorption, low infection risk, minimal training.
  • Disadvantages: local edema, limited drug compatibility, site rotation q24 hr.

Calculation & Review Highlights

• Resistance when flushing a cannula → BEST: remove & replace (risk of clot/occlusion); never force.

• Identifying hypertonic fluid: 5 % dextrose in 0.9 % NaCl (D5NS).

• Drip rate formula:
  \text{gtt/min} = \frac{\text{Volume (mL)} \times \text{Drop factor (gtt/mL)}}{\text{Time (min)}}
  • Example: \frac{1000\,\text{mL} \times 10\,\text{gtt/mL}}{6\,\text{hr} \times 60\,\text{min/hr}} = 28\,\text{gtt/min}.

• Life-threatening arrhythmia risk: IV potassium — must be on pump, never push.

• Fluid-volume excess indicators (select-all-that-apply): bounding pulse & crackles; NOT warmth at site, sweating, or fever.

Ethical, Safety, & Practice Implications

• Strict asepsis during insertion & maintenance → prevents CLABSI (central-line associated bloodstream infection).

• Accurate programming of EIDs and double-check of high-alert drugs (e.g., heparin, KCl) by two clinicians.

• Patient education: report pain, swelling, leaking; protect site; avoid bending joint with peripheral line.

• Documentation: site assessment, dressing integrity, infusion rate, patient response.

Memory Aide

IV FLUID TONICITY CHART

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