NLE Gastrointestinal Nursing — Nutritional & Metabolic SupportRevision Notes

Formulas

Exam Tips

• Memorize the BMI formula and both sets of cut-offs (global WHO and Asian/Filipino).
• NLE questions often test: 'Which lab value reflects recent nutritional status?' → Answer: PREALBUMIN.
• When a question mentions 'long-term nutritional assessment,' the answer involves ALBUMIN.
• Know that low albumin = edema risk (reduced oncotic pressure) — connects to fluid balance questions.

Key Points

• Nutritional assessment uses four domains: Anthropometric, Biochemical, Clinical, and Dietary (ABCD).
• BMI = weight in kg ÷ height in meters squared (m²). WHO global cut-offs: underweight <18.5, normal 18.5–24.9, overweight 25–29.9, obese ≥30 kg/m².
• Asian/Filipino-specific cut-offs (used in Philippine clinical practice): overweight ≥23 kg/m², obese ≥27.5 kg/m² — because cardiometabolic risk rises earlier in Asian populations.
• Significant unintentional weight loss: >5% in 1 month OR >10% in 6 months — this is a red flag for malnutrition.
• Prealbumin (transthyretin): half-life ~2 days — reflects RECENT nutritional intake; most sensitive early marker.
• Albumin: half-life ~3 weeks — reflects LONG-TERM nutritional status; low albumin also causes edema (hypoalbuminemia).
• Other biochemical markers: transferrin, total lymphocyte count (TLC), electrolytes (phosphate, potassium, magnesium are key in refeeding risk).
• Clinical signs of malnutrition: muscle wasting, temporal wasting, peripheral edema, poor skin turgor, brittle hair, poor wound healing.
• Dietary assessment: 24-hour recall, food frequency, appetite and intake history, food security status (relevant in Philippine community settings).

Definitions

Section Title

Nutritional Assessment

Common Mistakes

• Using global WHO BMI cut-offs for Filipino patients — always apply Asian cut-offs (overweight ≥23, obese ≥27.5) in clinical and NLE Philippine context.
• Confusing prealbumin with albumin — prealbumin is for RECENT status (days), albumin is for LONG-TERM status (weeks).
• Overlooking unintentional weight loss as a malnutrition indicator — significant even if BMI appears normal.
• Relying on albumin alone for acute nutritional monitoring — it is too slow to reflect recent changes.

Exam Tips

• Obesity management always starts with lifestyle modification (diet + exercise + behavior change) before moving to pharmacotherapy or surgery.
• Know the criteria for bariatric surgery: BMI ≥40, or BMI ≥35 with serious comorbidities (e.g., T2DM, hypertension).
• NLE may ask the FIRST nursing priority for an obese patient: assess comorbidities and establish realistic goals.

Key Points

• Obesity is defined as BMI ≥30 (global) or ≥27.5 (Asian/Filipino cut-off). Morbid/severe obesity = BMI ≥40.
• Pathophysiology: chronic energy surplus stored as adipose tissue, compounded by genetic, hormonal (leptin resistance, insulin resistance), behavioral, and environmental factors.
• Health risks: Type 2 diabetes mellitus (T2DM), hypertension, dyslipidemia, coronary artery disease (CAD), obstructive sleep apnea (OSA), non-alcoholic fatty liver disease (NAFLD), osteoarthritis, and increased risk of endometrial, breast, and colon cancers.
• Management ladder (stepwise approach): (1) Diet + physical activity + behavioral change → (2) Pharmacotherapy (orlistat, GLP-1 agonists: liraglutide, semaglutide) → (3) Bariatric surgery for severe obesity.
• Safe rate of weight loss: 0.5–1 kg per week — sustainable loss, not crash dieting.
• Nursing role: screen for comorbidities (BP, fasting blood glucose, lipid profile, sleep apnea screening), set realistic goals, provide non-judgmental care, motivational interviewing.
• AVOID weight stigma: stigma is a barrier to health-seeking behavior and worsens outcomes. Weight-inclusive, respectful care is an ethical and professional obligation under RA 9173 (Code of Ethics for Filipino Nurses).

Definitions

Section Title

Obesity: Assessment, Risks, and Nursing Management

Common Mistakes

• Setting unrealistic weight loss targets — patients should aim for 0.5–1 kg/week, not rapid crash-diet weight loss.
• Not screening obese patients for comorbidities like OSA, hypertension, and T2DM.
• Using stigmatizing language ('fat,' 'lazy') — this is unprofessional and violates nursing ethical standards under RA 9173.

Exam Tips

• NLE questions may present a child or adult with edema, normal or slightly elevated weight, skin changes — think KWASHIORKOR (protein deficiency).
• A patient who appears as 'skin and bones' with no edema = MARASMUS (total energy + protein deficit).
• Management priority for malnutrition: address the cause, start oral supplementation, monitor for refeeding syndrome.

Key Points

• Protein-energy malnutrition (PEM) has two classic forms: MARASMUS and KWASHIORKOR.
• MARASMUS: chronic total energy AND protein deficit → severe muscle and fat wasting, very low weight, no edema. The body 'consumes itself.'
• KWASHIORKOR: primarily protein deficit (may have adequate calories) → edema (hypoalbuminemia), distended abdomen, skin/hair changes (flag sign), but weight may appear deceptively normal or even high due to edema.
• Hospitalized patients often present with MIXED malnutrition (combined marasmus + kwashiorkor features) due to illness-related catabolism plus inadequate intake.
• Clinical signs: temporal and interosseous muscle wasting, peripheral edema, brittle/sparse hair, poor skin integrity, delayed wound healing, repeated infections (immunosuppression).
• Assessment criteria for significant malnutrition: BMI <18.5, unintentional weight loss >5% in 1 month or >10% in 6 months, low prealbumin and albumin.
• Management principle: ORAL ROUTE FIRST — small, frequent, energy-dense and protein-rich meals; oral nutritional supplements (ONS). Use enteral or parenteral feeding only when oral intake is insufficient.
• Treat the underlying cause of malnutrition (e.g., dysphagia, infection, poverty, depression).
• REFEEDING SYNDROME is the most critical complication of nutritional repletion in severely malnourished patients — see the next section.

Definitions

Section Title

Malnutrition: Types, Assessment, and Management

Common Mistakes

• Confusing marasmus and kwashiorkor — remember: Kwashiorkor = edema (K for edema/swelling); Marasmus = emaciation/wasting.
• Starting aggressive nutritional repletion in a malnourished patient without monitoring electrolytes — this triggers refeeding syndrome.
• Skipping oral supplementation and jumping straight to tube feeding — oral route is always preferred if the gut is functional.

Exam Tips

• NLE FAVORITE: 'A malnourished patient started on TPN develops arrhythmias and muscle weakness — what electrolyte is most likely abnormal?' → PHOSPHATE (hypophosphatemia).
• Remember the mnemonic PHKM for refeeding: PHosphatemia (hypo), Hypokalemia, hypoMagnesemia.
• Always give THIAMINE before or with initiation of carbohydrate-containing feeds in malnourished or alcoholic patients.
• Prevention = 'Start LOW and go SLOW' — this phrase directly answers NLE questions about refeeding syndrome prevention.

Key Points

• Refeeding syndrome occurs when a severely malnourished/starved patient is fed too rapidly — it is a LIFE-THREATENING metabolic emergency.
• During starvation, the body depletes intracellular phosphate, potassium, and magnesium but maintains relatively normal SERUM levels by pulling from cells.
• When feeding is restarted → insulin is released in response to carbohydrates → insulin drives glucose, phosphate, potassium, and magnesium INTO cells → sudden DROP in serum electrolytes.
• Key electrolyte disturbances: HYPOPHOSPHATEMIA (most dangerous and hallmark), HYPOKALEMIA, HYPOMAGNESEMIA.
• THIAMINE (Vitamin B1) is also rapidly depleted when carbohydrate metabolism is restarted — Wernicke encephalopathy can result.
• Clinical consequences: cardiac arrhythmias, respiratory failure (diaphragm weakness), neurological changes, cardiac failure, and DEATH if untreated.
• At-risk patients: prolonged starvation/fasting, anorexia nervosa, chronic alcoholism, post-operative patients with prolonged NPO, patients starting TPN or enteral feeding after long periods of no intake.
• PREVENTION — The 4 Rules of Refeeding Safety: (1) Start LOW and go SLOW — begin at 10–20 kcal/kg/day and advance gradually over days; (2) Give THIAMINE (Vitamin B1) BEFORE or WITH the initiation of feeding; (3) Monitor and REPLACE phosphate, potassium, and magnesium closely in the first days; (4) Limit simple carbohydrates initially to reduce insulin surge.
• Monitoring: serum phosphate, potassium, magnesium, and glucose daily (or more frequently in high-risk patients) during the first week of refeeding.

Definitions

Section Title

Refeeding Syndrome — High-Yield Safety Topic

Common Mistakes

• Starting aggressive high-calorie feeds immediately in a starved patient without electrolyte monitoring.
• Forgetting to give THIAMINE before restarting feeds — this can precipitate Wernicke encephalopathy.
• Not monitoring phosphate — this is the MOST CRITICAL electrolyte in refeeding syndrome, yet often overlooked.
• Attributing cardiac arrhythmias or respiratory failure in a malnourished patient to other causes without checking electrolytes.

Exam Tips

• NLE COMMON SCENARIO: Patient on NGT feeding develops fever, cough, increased respiratory rate — ASPIRATION PNEUMONIA. Priority intervention = stop feeding, suction, notify physician, position upright.
• Remember the sequence: Verify placement → Elevate HOB → Check GRV → Flush → Feed → Flush.
• pH ≤5.5 = gastric placement confirmed. pH >5.5 = may be in the lungs or intestine — do NOT feed, confirm with X-ray.
• Jejunal feeding (PEJ) → use CONTINUOUS method (not bolus) because the jejunum cannot accommodate large bolus volumes.

Key Points

• GOLDEN RULE: 'If the gut works, USE IT.' Enteral feeding is ALWAYS preferred over TPN — it preserves gut mucosal integrity (prevents bacterial translocation), is cheaper, and has fewer serious complications.
• Routes: SHORT-TERM (<4–6 weeks) — Nasogastric tube (NGT), Nasoduodenal, Nasojejunal. LONG-TERM (>4–6 weeks) — Percutaneous Endoscopic Gastrostomy (PEG), Jejunostomy.
• TUBE PLACEMENT VERIFICATION (mandatory before every feeding and medication administration): (1) Aspirate gastric contents — pH ≤5.5 confirms gastric placement; (2) Chest/abdominal X-ray is the GOLD STANDARD for confirming initial placement. Auscultation ('whoosh' test) ALONE is UNRELIABLE and should NOT be the sole method.
• ASPIRATION PREVENTION (priority safety intervention): Maintain head of bed (HOB) elevation at 30–45 degrees DURING feeding and for 30–60 minutes AFTER feeding.
• Check gastric residual volume (GRV) per institutional policy — high GRV indicates delayed gastric emptying and increased aspiration risk.
• FLUSH the tube with water: BEFORE and AFTER each feeding, and BEFORE and AFTER each medication to prevent clogging.
• Medications via NGT: give each medication SEPARATELY, flush between each drug, and NEVER crush enteric-coated (EC) or sustained-release (SR) medications — this destroys their protective mechanism.
• FORMULA TYPES: Polymeric (intact protein, standard — for functional gut), Elemental/Semi-elemental (pre-digested, hydrolyzed — for impaired absorption, e.g., Crohn's, short bowel), Disease-specific (renal, hepatic, diabetic, pulmonary).
• DELIVERY METHODS: Bolus/intermittent (gravity or syringe, several times daily — closest to normal eating, for gastric feeding in stable patients) vs. Continuous (pump-controlled over hours — better tolerated, preferred for jejunal feeding, critically ill or unstable patients).
• CONTAMINATION PREVENTION: Hang time for open feeding systems is typically 4–8 hours; use closed systems when available; refrigerate unused formula; use clean/aseptic technique.
• COMPLICATIONS: Aspiration pneumonia (most serious — prevention by HOB elevation), Diarrhea (from too-fast rate or hyperosmolar formula — slow the rate), Tube displacement/dislodgement, Tube clogging (flush regularly), Dumping-type symptoms (too-fast delivery).

Definitions

Section Title

Enteral Nutrition (Tube Feeding)

Common Mistakes

• Using auscultation alone to confirm NGT placement — this is UNSAFE; always confirm with pH test or X-ray.
• Forgetting to elevate the HOB during and after tube feeding — this is the NUMBER ONE aspiration prevention measure.
• Crushing enteric-coated or sustained-release medications for tube administration — destroys drug protection and alters pharmacokinetics.
• Not flushing the tube before and after medications/feedings — causes clogging and medication interactions.
• Mixing all medications together before administration through the tube — always give separately with flushes between each drug.

Exam Tips

• MOST COMMON NLE TPN TRAP: 'The TPN bag is empty and the next one is not ready — what do you do?' → Answer: Hang D10W (10% Dextrose in Water) at the SAME RATE. NEVER hang NSS.
• TPN complication questions: (1) Infection/sepsis = most common overall complication; (2) Hyperglycemia = most common early metabolic complication; (3) Rebound hypoglycemia = if stopped abruptly; (4) Pneumothorax = during insertion; (5) Air embolism = during tubing changes.
• Air embolism position: LEFT side + TRENDELENBURG + VALSALVA — this traps air in the right atrium away from the pulmonary circulation.
• The ONLY reason to not use enteral feeding is a NON-FUNCTIONAL gut — if the gut works, ALWAYS use it.

Key Points

• TPN delivers ALL nutritional needs INTRAVENOUSLY when the GI tract CANNOT BE USED (not just when it is inconvenient to use it).
• INDICATIONS for TPN: massive bowel resection/short-bowel syndrome, prolonged paralytic ileus (>7 days), severe pancreatitis with enteral intolerance, high-output enterocutaneous fistula, intractable vomiting/severe malabsorption, severe inflammatory bowel disease.
• TPN CONTENTS: Hypertonic dextrose (high concentration, e.g., 20–70%) + crystalline amino acids + lipid emulsion (fat) + electrolytes (Na, K, Mg, Ca, Phos) + vitamins + trace elements (zinc, selenium, copper).
• CENTRAL LINE ONLY: TPN MUST be administered through a CENTRAL venous catheter (subclavian, internal jugular, or PICC line) because the high dextrose concentration is HYPEROSMOLAR (>900 mOsm/L) and will SCLEROSE/DAMAGE peripheral veins. EXCEPTION: Peripheral Parenteral Nutrition (PPN) uses lower concentration and is only for short-term use.
• USE AN INFUSION PUMP: ALWAYS. Never gravity-drip TPN.
• STRICT ASEPTIC TECHNIQUE: TPN is a rich growth medium for bacteria and fungi. CATHETER-RELATED BLOODSTREAM INFECTION (CRBSI) / SEPSIS is the MOST COMMON and MOST DANGEROUS complication of TPN.
• NEVER STOP TPN ABRUPTLY: Sudden cessation causes REBOUND HYPOGLYCEMIA — the pancreas is still secreting high insulin levels against the high-glucose load. TAPER the rate down over hours. If the next TPN bag is unavailable or delayed, HANG 10% DEXTROSE (D10W) at the SAME RATE as the TPN was running. NEVER substitute plain normal saline (NSS).
• MONITOR BLOOD GLUCOSE every 4–6 hours: HYPERGLYCEMIA is the most common early metabolic complication. Use sliding-scale or protocol-based insulin as ordered. Target glucose 140–180 mg/dL in most ICU patients.
• DO NOT SPEED UP OR SLOW DOWN TPN to 'catch up' if behind schedule — this destabilizes blood glucose. Keep the ORDERED RATE.
• DEDICATED LINE RULE: Do NOT use the TPN port/lumen for other IV medications, blood products, or CVP measurements UNLESS a dedicated separate lumen is designated for TPN.
• Change TPN tubing every 24 hours (per most Philippine hospital protocols); change dressing over central line insertion site per protocol (usually every 48–72 hours for transparent dressings).
• AIR EMBOLISM prevention during tubing changes: Position patient in LEFT LATERAL DECUBITUS + TRENDELENBURG (head down); have patient perform VALSALVA MANEUVER during disconnection/reconnection.
• TRANSITIONING OFF TPN: As gut function returns, advance to enteral/oral feeding simultaneously while TAPERING TPN gradually over hours. Continue glucose monitoring during and after transition because insulin secretion lags behind the falling glucose infusion.

Definitions

Section Title

Total Parenteral Nutrition (TPN)

Common Mistakes

• Administering TPN through a peripheral IV — will cause severe phlebitis and vein sclerosis.
• Stopping TPN abruptly — causes rebound hypoglycemia; always taper and replace with D10W if the next bag is delayed.
• Substituting normal saline for TPN when the bag is unavailable — NSS has NO dextrose and will not prevent hypoglycemia.
• Speeding up TPN to 'catch up' missed hours — causes hyperglycemia and metabolic instability.
• Piggybacking IV medications or blood into the TPN line — risk of contamination, precipitation, and infection.
• Failing to monitor blood glucose regularly while patient is on TPN.
• Not changing tubing at required intervals — increases infection risk.

Exam Tips

• Dumping syndrome teaching: 'Small meals, low carbs, fluids BETWEEN not WITH meals, lie down after eating.' This is a direct NLE answer.
• Anastomotic leak = TACHYCARDIA is the first sign — before fever and pain become severe.
• Lifelong supplements after bariatric surgery: Iron, B12, Folate, Calcium, Vit D, Thiamine, Zinc — memorize this list.
• Bariatric surgery criteria: BMI ≥40, or BMI ≥35 with comorbidities — these numbers are commonly tested.

Key Points

• INDICATIONS for bariatric surgery: BMI ≥40 kg/m², OR BMI ≥35 kg/m² with serious obesity-related comorbidities (T2DM, hypertension, OSA, severe dyslipidemia).
• COMMON PROCEDURES: (1) Sleeve Gastrectomy — removes ~80% of stomach, creating a sleeve-shaped stomach; restrictive only. (2) Roux-en-Y Gastric Bypass (RYGB) — creates a small gastric pouch and bypasses part of the small intestine; both restrictive AND malabsorptive.
• MOST CRITICAL POST-OP COMPLICATION to monitor: ANASTOMOTIC LEAK — occurs when the surgical join between bowel segments breaks down, allowing GI contents to leak into the abdominal cavity. EARLY SIGNS: Tachycardia (first and most sensitive sign), fever, increasing abdominal pain, restlessness, and anxiety. TREAT AS AN EMERGENCY.
• Other post-op concerns: VTE (DVT/pulmonary embolism) — prevent with early ambulation, sequential compression devices (SCD), and pharmacological prophylaxis (LMWH). Airway issues — many bariatric patients have OSA; monitor oxygen saturation and use CPAP if indicated.
• DUMPING SYNDROME: Most common after Roux-en-Y gastric bypass due to rapid emptying of hyperosmolar gastric contents into the small bowel. TWO TYPES: (1) Early dumping (15–30 minutes after eating): GI symptoms — cramping, nausea, explosive diarrhea; AND vasomotor symptoms — tachycardia, flushing, diaphoresis, dizziness (from fluid shift into the gut). (2) Late dumping (1–3 hours after eating): hypoglycemia from reactive insulin surge.
• DUMPING SYNDROME PREVENTION (patient teaching): (1) Eat SMALL, FREQUENT meals (5–6 small meals/day); (2) Choose LOW simple carbohydrate, HIGHER protein and fat foods; (3) Drink fluids BETWEEN meals, NOT with meals; (4) Eat SLOWLY and chew thoroughly; (5) LIE DOWN or rest after eating to slow gastric emptying.
• LIFELONG NUTRITIONAL SUPPLEMENTATION is MANDATORY after bariatric surgery due to reduced gastric acid, bypassed absorptive surfaces, and reduced food intake.
• Required lifelong supplements: Iron, Vitamin B12, Folate, Calcium (calcium citrate preferred, not carbonate — better absorbed without acid), Vitamin D, Thiamine (B1), and Zinc.
• Post-op diet progression: Clear liquids → Full liquids → Pureed foods → Soft foods → Regular diet (over 4–8 weeks per protocol).

Definitions

Section Title

Bariatric Surgery: Nursing Care and Complications

Common Mistakes

• Missing the earliest sign of anastomotic leak (TACHYCARDIA) — NLE questions often present tachycardia + fever + worsening pain as the clue.
• Forgetting that lifelong supplementation is MANDATORY after bariatric surgery — deficiencies develop insidiously over months to years.
• Teaching a post-bariatric patient to drink fluids WITH meals — this is WRONG and worsens dumping syndrome.
• Using calcium carbonate supplements after bariatric surgery — calcium CITRATE is preferred because it does not require stomach acid for absorption.
• Not assessing for OSA in post-bariatric patients — many have OSA and need airway monitoring.

Exam Tips

• NLE scenario: Macrocytic anemia + peripheral neuropathy + ataxia = VITAMIN B12 deficiency (not folate — folate has NO neurological signs).
• Scurvy (Vitamin C deficiency) = bleeding gums + poor wound healing — common NLE distractor.
• Post-bariatric patient with confusion + eye movement abnormality = THIAMINE (Wernicke) — give IV thiamine immediately.
• Remember: ZINC = Wound healing + Taste + Dermatitis — the '3Ds' of zinc deficiency.

Key Points

• IRON deficiency: microcytic hypochromic anemia, fatigue, pallor, koilonychia (spoon-shaped nails), pica, angular stomatitis.
• VITAMIN B12 deficiency: macrocytic (megaloblastic) anemia + NEUROLOGICAL signs — peripheral paresthesias (numbness/tingling), ataxia, subacute combined degeneration of the spinal cord. Common after total gastrectomy or RYGB.
• FOLATE deficiency: macrocytic anemia (without neurological signs — key distinction from B12 deficiency), glossitis.
• VITAMIN A deficiency: night blindness (earliest sign), xerophthalmia, Bitot's spots, dry rough skin, impaired immune function.
• VITAMIN C (Ascorbic Acid) deficiency — SCURVY: perifollicular hemorrhages, bleeding/swollen gums, poor wound healing, corkscrew hairs, joint pain.
• VITAMIN D and CALCIUM deficiency: bone pain, osteomalacia (softening of bones in adults), rickets (children), hypocalcemic tetany (Chvostek's sign, Trousseau's sign), muscle cramps.
• THIAMINE (Vitamin B1) deficiency: (1) Wet beriberi — heart failure, peripheral edema, dilated cardiomyopathy; (2) Dry beriberi — peripheral neuropathy; (3) Wernicke encephalopathy — confusion, ophthalmoplegia, ataxia (triad); common in alcoholism and refeeding syndrome.
• ZINC deficiency: impaired wound healing, altered/loss of taste (dysgeusia/ageusia), dermatitis (especially perioral and perianal rash), alopecia, impaired immune function.
• MAGNESIUM deficiency: muscle weakness, tremors, tetany, cardiac arrhythmias — commonly co-exists with hypokalemia and hypocalcemia.

Definitions

Section Title

Micronutrient Deficiencies: Clinical Recognition

Common Mistakes

• Confusing B12 and folate deficiency — BOTH cause macrocytic anemia, but ONLY B12 deficiency causes neurological signs.
• Missing zinc deficiency as a cause of poor wound healing — zinc is often overlooked but is essential for tissue repair.
• Not associating thiamine deficiency with refeeding syndrome — thiamine must be given BEFORE carbohydrate refeeding.