7.5 IV and Parenteral Therapies

Fluids, Blood, and Nutrition by Vein

Parenteral therapy questions reward knowing where the fluid goes (tonicity), which line is required, and the exact transfusion protocol. Tonicity is compared to the ~285-300 mOsm/L of blood plasma.

IV Solution Tonicity

Tested nuances: D5W is isotonic in the bag but becomes hypotonic once the dextrose is metabolized (never use for fluid resuscitation alone or in head injury). Lactated Ringer's is avoided in liver disease (the liver cannot convert lactate) and in hyperkalemia (it contains potassium). 0.9% NS in large volumes can cause hyperchloremic metabolic acidosis.

IV Access Devices

Vesicants, hyperosmolar fluids (>900 mOsm/L), and TPN require a central device because they damage peripheral veins.

Blood and Blood Products

Transfusion protocol (memorize the sequence):

1. Confirm prescriber order and informed consent; verify type-and-crossmatch.
2. Two licensed staff verify patient identity, ABO/Rh type, unit number, and expiration at the bedside.
3. Hang with Y-tubing and 0.9% NS only — no dextrose, no LR, no added meds.
4. Start slowly (~2 mL/min) and stay with the patient the first 15 minutes, when most severe reactions begin.
5. Take vital signs before, at 15 minutes, and at completion; finish within 4 hours.

Transfusion Reactions

The single most-tested point: any acute reaction → stop the transfusion first, then keep the line open with normal saline. "Slow the rate" is a trap for a true hemolytic reaction.

Total Parenteral Nutrition (TPN)

TPN delivers complete nutrition (dextrose, amino acids, lipids, electrolytes, vitamins, trace elements) for patients who cannot use the gut.

• Central line required because the solution is hyperosmolar; use a dedicated lumen and give no other meds through it.
• Use a filter (0.22 micron non-lipid; 1.2 micron lipid-containing).
• Never stop abruptly — taper or hang D10W to prevent rebound hypoglycemia from the body's elevated insulin output.
• If the next bag is unavailable, hang D10W, not plain saline.

Peripheral parenteral nutrition (PPN) is a lower-concentration, short-term (7-10 day) supplement that can run in a peripheral vein.

Priorities the Exam Rewards

Parenteral therapy items cluster around a few decisions, and knowing the default action for each makes them reliable points. For fluids, let the patient's problem choose the tonicity: a dehydrated cell needs a hypotonic shift inward, a hyponatremic emergency may need careful hypertonic correction, and routine volume replacement uses isotonic saline or Lactated Ringer's — while you watch every isotonic and hypertonic infusion for fluid overload signaled by crackles, jugular venous distension, and a bounding pulse.

For blood, the protocol is non-negotiable: verify with a second licensed nurse, run with 0.9% NS only, stay for the first 15 minutes, and stop the transfusion at the first sign of any acute reaction, keeping the saline line open. For nutrition, remember that TPN is a hyperosmolar central-line therapy that demands glucose monitoring and a controlled taper, never an abrupt stop. The thread tying these together is anticipation — the safe nurse predicts the most likely complication of each therapy and is ready to act before it becomes an emergency, which is exactly the clinical judgment the NCLEX-PN is built to measure.