AIM LEARNING CYCLE · STUDENT MEMORY SUPPORT
Topic 3 — Clinical Nutritional Support
Enteral & Parenteral Nutrition
Final Year MBBS · MS Module · KMU Curriculum · High-yield revision
1. High-Yield Flashcards
Tap each question to reveal the answer.
Which clues can reveal malnutrition even when BMI is normal or high?
Unintentional weight loss, reduced intake and muscle wasting.
What is the preferred first route when swallowing and gut function are adequate?
Optimized oral food intake, with supplements if needed.
When is enteral tube feeding preferred to parenteral nutrition?
When oral intake is inadequate but the gastrointestinal tract works.
When is parenteral nutrition appropriate?
When the gut cannot safely deliver or absorb adequate nutrition.
Which tube is commonly used for short-term gastric enteral feeding?
Nasogastric (NG) tube.
Which access is considered when long-term gastric feeding is anticipated?
Percutaneous endoscopic gastrostomy (PEG).
What must be established before NG feeding begins?
Correct tube position, using approved confirmation methods.
Is air-insufflation auscultation sufficient to confirm NG tube placement?
No. The “whoosh” test is unreliable.
What is an important NG insertion precaution after major facial trauma?
Avoid blind nasal insertion if a basal skull fracture is suspected.
What PEG complication is suggested by severe pain and peritoneal signs?
Possible peritonitis; urgent assessment is required.
Why is central venous access used for concentrated parenteral feeds?
High blood flow dilutes hyperosmolar solutions.
Which vascular complication may cause catheter-side arm swelling?
Catheter-associated venous thrombosis.
Which electrolytes commonly fall in refeeding syndrome?
Phosphate, potassium and magnesium.
Can refeeding syndrome occur with oral nutrition?
Yes. It can occur with oral, enteral or parenteral feeding.
How is recorded fluid balance calculated?
Total measured intake minus total measured output.
What should counselling before PEG placement include?
Purpose, alternatives, consent, complications, stoma care and warning signs.
2. Mnemonics
Mnemonic Title
Choosing the feeding route
Mnemonic Word: O–E–P
Meaning: Oral if safe and adequate → Enteral if the gut works but oral intake fails → Parenteral if adequate gut feeding is not possible.
Mnemonic Title
Refeeding electrolyte pattern
Mnemonic Word: P–K–Mg
Meaning: Phosphate, K (potassium) and Mg (magnesium) may fall after restarting nutrition.
Mnemonic Title
PEG-site danger clues
Mnemonic Word: P–B–L–I
Meaning: Pain, Bleeding, Leakage and Infection are important findings to assess after PEG insertion.
3. Memory Tables
Oral, enteral and parenteral nutrition
| Feature | Oral | Enteral | Parenteral |
|---|---|---|---|
| Delivery | Mouth | Feeding tube into gut | Intravenous vein |
| When useful | Safe swallowing | Gut works; oral intake inadequate | Gut unusable or insufficient |
| Notable concern | Intake may remain low | Aspiration / tube issues | Catheter / metabolic issues |
NG tube versus PEG
| Feature | Nasogastric tube | PEG |
|---|---|---|
| Typical duration | Short-term | Longer-term |
| Route | Nose → stomach | Abdominal wall → stomach |
| Major care focus | Position and fixation | Stoma and tube care |
| Important risks | Displacement / aspiration | Infection / leakage / peritonitis |
4. Rapid Revision Points — Last-Minute Revision
Must Remember:
- Malnutrition assessment includes recent weight change, intake and muscle loss—not BMI alone.
- Escalate from oral support according to swallowing safety and ability to meet requirements.
- Dysphagia with a functioning gut does not automatically justify parenteral nutrition.
- Possible ileus or obstruction warrants reassessment before gastrointestinal feeding.
- NG displacement may follow vomiting, coughing or a changed external tube marking.
- PEG does not abolish aspiration risk.
- Peripheral veins poorly tolerate concentrated parenteral formulations.
- Unexpected fever on central parenteral nutrition raises concern for line infection.
- Refeeding syndrome requires early risk recognition and electrolyte monitoring.
- Positive fluid balance must be interpreted with oedema, weight, urine output and other findings.
5. Clinical Memory Hooks
Normal BMI + substantial recent weight loss → Malnutrition remains possible
Unable to swallow + functional intestine → Enteral feeding can use the gut
Coughing after possible NG displacement → Stop feeding and verify tube position
Severely malnourished + falling phosphate after feeding → Suspect refeeding syndrome
6. Starred High-Yield Exam Points
- Use the gut when it can deliver adequate nutrition; oral or enteral support comes before parenteral support when appropriate.
- NG placement must be confirmed reliably before feed, water or medication—never by the “whoosh” test alone.
- NG is generally short-term; PEG is considered for prolonged gastric access.
- Parenteral nutrition requires monitoring for catheter infection, thrombosis and metabolic disturbances.
- Refeeding syndrome may follow any feeding route: phosphate, potassium and magnesium can decrease.
- Fluid balance = measured intake − measured output; the number alone does not diagnose overload.