A patient's TPN infusion is complete, but the next bag has not arrived from pharmacy. The nurse should:

Hang D10W at the same rate as the TPN. When TPN must be interrupted or runs out, hang D10W at the same rate to prevent rebound hypoglycemia. The high dextrose content of TPN stimulates insulin release; abruptly stopping the dextrose source causes hypoglycemia. Never abruptly discontinue TPN without providing an alternative glucose source.

TPN is administered through a central venous catheter primarily because:

TPN has high osmolarity that would cause peripheral vein damage. TPN has a very high osmolarity (> 900 mOsm/L) due to concentrated dextrose. This would cause severe phlebitis and tissue damage if infused through a peripheral vein. Central veins have higher blood flow that dilutes the solution immediately, making administration safe.

A malnourished patient has just started TPN. Within 48 hours, the nurse notes muscle weakness, respiratory difficulty, and a potassium level of 2.8 mEq/L. The nurse recognizes these as signs of:

Refeeding syndrome. Refeeding syndrome occurs when severely malnourished patients receive nutrition (including TPN). Glucose stimulates insulin, which drives potassium, phosphorus, and magnesium into cells, causing dangerous electrolyte deficiencies. Signs include weakness, arrhythmias, and respiratory failure. Prevention involves starting TPN slowly and supplementing electrolytes.

Which nursing action is appropriate when administering TPN?

Use a dedicated lumen exclusively for TPN. TPN should infuse through a dedicated lumen to prevent contamination and incompatibility reactions. Never piggyback medications, draw blood, or infuse other solutions through the TPN line. TPN tubing should be changed every 24 hours (every 12 hours for lipid-containing formulations) due to infection risk.

7.9 Total Parenteral Nutrition (TPN) | NCLEX-RN (Registered Nurse) | Free Exam Prep

Total Parenteral Nutrition (TPN)

Total Parenteral Nutrition provides complete nutrition intravenously when the gastrointestinal tract cannot be used. Understanding TPN administration, monitoring, and complications is essential for safe nursing practice.

Indications for TPN

Condition	Rationale
Bowel obstruction	Cannot absorb nutrients enterally
Short bowel syndrome	Insufficient intestinal length
Severe pancreatitis	Bowel rest required
Prolonged ileus	GI tract non-functional
Severe malabsorption	Cannot absorb nutrients
High-output fistulas	GI contents bypassing absorption
NPO > 7 days	Nutrition required but enteral not possible
Severe burns	High metabolic needs, GI dysfunction

TPN Components

Component	Purpose	Considerations
Dextrose (Glucose)	Primary calorie source	Causes hyperglycemia; 50-70% of calories
Amino Acids	Protein for tissue repair	Renal monitoring needed
Lipid Emulsion	Essential fatty acids, calories	Given separately or as 3-in-1
Electrolytes	Fluid/electrolyte balance	Individualized based on labs
Vitamins	Metabolic cofactors	Added daily
Trace Elements	Zinc, copper, chromium, etc.	Essential for metabolism

Central vs. Peripheral Parenteral Nutrition

Feature	Central TPN	Peripheral PN (PPN)
Dextrose concentration	Up to 70%	Maximum 10%
Osmolarity	> 900 mOsm/L	< 900 mOsm/L
Access	Central line required	Peripheral IV acceptable
Duration	Long-term (weeks to months)	Short-term (< 2 weeks)
Calories	Full nutritional support	Supplemental nutrition

Critical Point: High-concentration TPN causes severe phlebitis if given through a peripheral line. Central venous access is required for standard TPN.

Administration Guidelines

Access Requirements:

Central venous catheter (CVC)
PICC line
Implanted port

Dedicated Lumen:

TPN should have its own lumen
Do NOT use TPN line for blood draws, meds, or other infusions
Reduces infection risk

Infusion Rate:

Start at 40-50 mL/hour
Increase gradually over 24-48 hours
Goal rate achieved per order
Do NOT abruptly stop (rebound hypoglycemia)

Monitoring Parameters

Parameter	Frequency	Normal Values
Blood glucose	Every 4-6 hours initially	70-180 mg/dL
Electrolytes (K+, Na+, Mg2+, PO4)	Daily initially	Within normal limits
BUN/Creatinine	Daily to weekly	Renal function
Liver function tests	Weekly	ALT, AST, bilirubin
Triglycerides	Weekly if lipids given	< 400 mg/dL
Weight	Daily	Steady gain appropriate
I&O	Every shift	Fluid balance

Complications and Nursing Interventions

Metabolic Complications

Hyperglycemia (Most Common)

Cause	Intervention
High dextrose load	Monitor BG every 4-6 hours
Stress response	Administer insulin as ordered
Steroid use	May need insulin drip

Hypoglycemia

Cause	Intervention
Abrupt TPN discontinuation	Never stop abruptly
Excessive insulin	Taper TPN gradually
TPN bag runs out	Hang D10W immediately

Refeeding Syndrome

Cause	Signs	Prevention
Starting TPN after starvation	↓ Potassium, phosphorus, magnesium	Start TPN slowly
Cells rapidly take up electrolytes	Cardiac arrhythmias, weakness	Supplement electrolytes
	Respiratory failure	Monitor closely first 3-5 days

Fluid and Electrolyte Complications

Imbalance	Signs	Intervention
Fluid overload	Edema, crackles, JVD	Reduce rate, diuretics
Hypokalemia	Weakness, arrhythmias	Add potassium to TPN
Hypernatremia	Altered mental status	Adjust sodium content
Hypophosphatemia	Weakness, respiratory failure	Supplement phosphorus

Infection (Catheter-Related)

Signs:

Fever, chills
Redness at catheter site
Elevated WBC
Positive blood cultures

Prevention:

Strict aseptic technique
Dedicated TPN lumen
Change TPN bag and tubing every 24 hours
Change lipid tubing every 12 hours
Dressing changes per protocol

Intervention:

Obtain blood cultures
Notify provider
May need to remove catheter
Antibiotics as ordered

Critical Nursing Actions

If TPN Must Be Stopped:

NEVER stop abruptly (causes hypoglycemia)
Hang D10W at same rate to prevent rebound hypoglycemia
Taper gradually if planned discontinuation

Never Add to TPN:

No IV push medications
No piggyback infusions
No blood draws from TPN lumen
Incompatibilities can cause precipitation

Lipid Administration:

Given separately or as 3-in-1 mixture
Milky white appearance (don't confuse with contamination)
Change tubing every 12 hours (bacterial growth medium)
Monitor triglyceride levels

Cyclic TPN

Some patients receive TPN over 10-14 hours (usually overnight) instead of 24 hours:

Benefits:

More normal lifestyle
Reduces hepatic complications
Allows daytime mobility

Requirements:

Must tolerate rate increase
Gradual tapering at end of cycle
Glucose monitoring at end of cycle

Transitioning Off TPN

When transitioning to enteral nutrition:

Start tube feeding or oral diet
Decrease TPN as enteral intake increases
Taper TPN gradually over 24-48 hours
Monitor for hypoglycemia
Discontinue when enteral meets 60-75% of needs

On the Exam

Central line required for TPN (high osmolarity)
Monitor glucose frequently (hyperglycemia)
Never stop abruptly (hang D10W)
Dedicated line - no additives
Refeeding syndrome risk in malnourished patients

NCLEX-RN

1Introduction

2Chapter 2: Management of Care

3Chapter 3: Safety and Infection Prevention and Control

4Chapter 4: Health Promotion and Maintenance

5Chapter 5: Psychosocial Integrity

6Chapter 6: Basic Care and Comfort

7Chapter 7: Pharmacological and Parenteral Therapies

8Chapter 8: Reduction of Risk Potential

9Chapter 9: Physiological Adaptation

Key Takeaways