NLE Gastrointestinal Nursing — Nutritional & Metabolic SupportSummary

Comprehensive nutritional assessment integrates three domains: (1) Anthropometric measurements—weight, height, and Body Mass Index (BMI). BMI is calculated as weight in kilograms divided by height in meters squared (BMI = kg ÷ m²). WHO categories apply universally but Southeast Asian populations, including Filipinos, have lower risk thresholds: underweight <18.5, normal 18.5–22.9, overweight 23–27.4, and obese ≥27.5 kg/m² (compared to WHO's obese ≥30). Unintentional weight loss >5% in 1 month or >10% in 6 months is significant. (2) Biochemical markers—serum albumin (half-life ~3 weeks, reflects long-term nutritional status) and prealbumin/transthyretin (half-life ~2 days, more sensitive to recent dietary intake). Both are synthesized by the liver and decline in malnutrition, illness, and infection. Normal albumin is 3.5–5.5 g/dL; normal prealbumin is 20–40 mg/dL. Additional markers include transferrin, total lymphocyte count, and electrolytes. (3) Clinical/dietary findings—visual inspection for muscle wasting, edema, skin changes (pallor, poor healing), hair loss, and oral mucosa changes; detailed dietary history; and assessment of functional capacity. Integration of all three domains prevents misclassification (e.g., edematous malnutrition can mask weight loss).

Malnutrition exists on a spectrum ranging from marasmus (chronic, total energy deficit with severe wasting, muscle loss, and deceptively low weight) to kwashiorkor (primary protein deficit with hepatic synthesis failure, resulting in edema, ascites, and maintained or increased body weight that masks protein loss). In hospitalized adults, mixed or intermediate forms predominate—acute illness superimposed on chronic poor intake. Manifestations include: progressive unintentional weight loss; visible muscle wasting (particularly temporalis, trapezius, and limbs); weakness and fatigue limiting activities of daily living; delayed wound healing and poor skin integrity (related to collagen synthesis); peripheral edema and ascites (from hypoalbuminemia); immunosuppression (reduced cell-mediated immunity and complement function) leading to increased infection risk; and micronutrient deficiencies (iron, vitamin B12, folate, vitamin D, zinc, thiamine). In the Philippine context, PEM is common in rural and low-income populations and is exacerbated by infectious diseases (tuberculosis, enteric infections) and chronic conditions (diabetes, chronic kidney disease).

Refeeding syndrome is a life-threatening constellation of metabolic derangements that occurs when a severely malnourished or starved patient is fed (orally, enterally, or parenterally) too rapidly or in excessive quantities. During starvation, the body shifts to catabolism and mobilizes fat and protein for energy; intracellular phosphate, potassium, and magnesium deplete. Upon refeeding, insulin surges in response to glucose and amino acids, driving these electrolytes intracellularly for anabolism—causing severe extracellular (serum) HYPOphosphatemia, HYPOkalemia, and HYPOmagnesemia. Simultaneously, thiamine (vitamin B1) is consumed rapidly in carbohydrate metabolism and becomes depleted if not supplemented, risking Wernicke encephalopathy. Consequences include: cardiac arrhythmias (from hypokalemia and hypophosphatemia), seizures, tetany (from hypophosphatemia and hypomagnesemia), respiratory muscle weakness and failure, rhabdomyolysis, encephalopathy, coma, and death. Prevention requires: (1) identification of at-risk patients—those with BMI <16, unintentional weight loss >15% in 3 months, minimal oral intake for >10 days, or history of anorexia nervosa; (2) thiamine supplementation (100 mg IV or PO daily) before or concurrent with feeding; (3) slow initiation of feeding at 50% of estimated caloric needs, advancing gradually over 3–7 days; (4) frequent electrolyte monitoring (phosphate, potassium, magnesium, calcium) in the first 3–5 days; (5) aggressive electrolyte replacement; and (6) monitoring for signs of organ dysfunction (arrhythmias, confusion, weakness).

The principle 'if the gut works, use it' underpins enteral nutrition's primacy: enteral feeding preserves intestinal mucosal integrity, maintains the gut barrier, reduces bacterial translocation, is less expensive, and carries lower rates of infectious and metabolic complications than TPN. Routes include: (1) Short-term (days to weeks)—nasogastric tube (NGT, passed through the naris into the stomach) or nasointestinal tube (placed in the duodenum or jejunum for high-aspiration-risk patients). (2) Long-term (≥4–6 weeks)—percutaneous endoscopic gastrostomy (PEG, surgically or endoscopically placed into the stomach) or percutaneous endoscopic jejunostomy (PEJ). Tube verification is essential: before every feed or medication administration, (a) aspirate gastric contents and test pH—gastric pH is ≤5.5 (acidic); if pH >6, the tube may be in the small intestine, and further confirmation is needed; (b) obtain abdominal X-ray to confirm initial placement (is the tube tip in the desired location?). Auscultation alone ('whoosh' test) is no longer recommended as it lacks sensitivity and specificity. Aspiration—pulmonary inhalation of gastric contents—is the most serious complication, leading to aspiration pneumonia, acute respiratory distress, and death. Prevention strategies: (1) Keep the head of bed elevated 30–45° during feeding and for at least 30–60 minutes after feeding. (2) Assess gastric residual volume (GRV) per institutional protocol; volumes >250–500 mL may indicate delayed gastric emptying and warrant slowing the infusion or adding prokinetic agents. (3) Flush the tube with 20–30 mL of water before and after each feed and each medication to maintain patency and prevent clogging; use sterile or boiled cooled water if immunocompromised. (4) Administer medications separately, never crushing enteric-coated or sustained-release tablets, as this destroys their designed absorption profile. Formulas range from polymeric (intact nutrients—standard, for normal absorption) to elemental/semi-elemental (predigested amino acids and simple sugars—for impaired digestion or absorption, e.g., pancreatitis, short-bowel syndrome) to disease-specific (renal, hepatic, diabetic, pulmonary—tailored electrolyte, protein, carbohydrate, and fat ratios). Delivery methods: bolus/intermittent (gravity or syringe, multiple times daily—most physiologic, closest to normal meals, suitable for gastric feeding) versus continuous (pump-regulated over many hours—better tolerated, preferred for jejunal feeding and critically ill patients). Complications include aspiration (most serious), diarrhea (from hyperosmolar formula, rapid rate, or infectious causes), tube malposition or clogging, abdominal distension, dumping-like symptoms (rapid small-intestine filling), and refeeding syndrome if initiated too aggressively in malnourished patients.

TPN is complete intravenous nutrition reserved for when the GI tract cannot be used for ≥5–7 days: massive bowel resection or short-bowel syndrome, prolonged paralytic ileus unresponsive to medical therapy, severe acute pancreatitis, intractable vomiting, high-output enterocutaneous fistula, or severe malabsorption. TPN composition includes: (1) Dextrose (5–35% concentration)—the primary energy source and highly osmolar; (2) Amino acids (3.5–15%)—for protein synthesis; (3) Lipid emulsion (10–20%)—providing essential fatty acids and additional calories; (4) Electrolytes (sodium, potassium, chloride, calcium, magnesium, phosphate)—tailored to patient needs; (5) Vitamins (fat- and water-soluble) and trace elements (zinc, copper, chromium, manganese, selenium, iodine). The dextrose concentration (20–35%) is hyperosmolar (>600 mOsm/L) and MUST be infused through a CENTRAL venous catheter (subclavian, internal jugular, or PICC line with the tip in the superior vena cava). Peripheral infusion of hypertonic TPN causes thrombophlebitis and tissue necrosis. A lower-osmolarity peripheral PN exists but is limited to short-term use and lower caloric provision. Administration safety (NLE critical): (1) Use an electronic infusion pump to maintain precise, consistent flow and prevent rapid fluctuations in glucose. (2) Employ strict aseptic technique during preparation, handling, tubing changes, and dressing changes—TPN is an ideal culture medium (rich in glucose, amino acids, lipids) for bacterial and fungal overgrowth. Catheter-related bloodstream infection (CRBSI) is the most common infectious complication and manifests as fever, chills, leukocytosis, and positive blood cultures from the central line. (3) NEVER stop TPN abruptly—the infusing high-concentration glucose stimulates sustained pancreatic insulin secretion; sudden cessation causes rebound HYPOGLYCEMIA within 1–2 hours, risking seizures, coma, and cardiac arrhythmias. Instead: taper the infusion rate downward over several hours, or if the next bag is unavailable/delayed, hang D10W (10% dextrose) at the same rate as the ordered TPN rate to prevent hypoglycemia. Never substitute plain saline or normal saline. (4) Blood glucose must be monitored every 4–6 hours initially, then daily once stable; hyperglycemia is common early (from the glucose load and stress response) and is managed with sliding-scale regular insulin per protocol. (5) Do NOT adjust the infusion rate to 'catch up' if behind schedule—this destabilizes glucose control and risks hypoglycemia or hyperglycemia. Maintain the prescribed rate; if behind, extend the duration over the next interval rather than speeding up. (6) The TPN line is dedicated to TPN only; do not use it for other IV medications, blood draws, CVP monitoring, or blood transfusions unless the catheter has multiple lumens with one designated for TPN. Mixed-use ports increase infection risk. (7) Tubing and dressing changes follow institutional protocol (typically tubing every 24 hours, dressing every 2–3 days or when soiled/loose). (8) Complications: CRBSI (fever, positive blood cultures), air embolism (during tubing changes—risk is reduced by having the patient perform Valsalva maneuver during line connection and positioning the patient left side in Trendelenburg to trap air in the right atrium away from the pulmonary artery), pneumothorax (during central-line insertion), catheter malposition or migration, thrombosis (catheter-related or TPN-induced), hyperglycemia (managed with insulin), rebound hypoglycemia (managed by tapering), refeeding syndrome (if nutritional needs are rapidly escalated in a malnourished patient), and metabolic bone disease and hepatic dysfunction with prolonged TPN use (from micronutrient imbalances and metabolic stress). Monitoring includes daily weight, strict intake and output, blood glucose, electrolytes (sodium, potassium, chloride, bicarbonate), phosphate, magnesium, calcium, liver function tests (bilirubin, transaminases, alkaline phosphatase), and triglycerides (target <200 mg/dL on lipid-containing TPN).

Obesity is excess adiposity resulting from sustained energy intake exceeding expenditure; it is multifactorial, involving genetic predisposition, behavioral factors (dietary habits, physical inactivity), environmental influences (food environment, food costs in the Philippines), and metabolic factors (insulin resistance, leptin dysfunction). BMI ≥30 kg/m² defines obesity globally; however, Southeast Asian populations (including Filipinos) show increased cardiometabolic risk at lower BMI thresholds, so overweight is defined as BMI 23–27.4 and obese as ≥27.5. Obesity is associated with type 2 diabetes mellitus, hypertension, dyslipidemia, coronary artery disease, obstructive sleep apnea, non-alcoholic fatty liver disease (NAFLD), osteoarthritis (from excess joint loading), certain cancers (breast, endometrial, colorectal, prostate), and psychological/social burden (stigma, discrimination, reduced quality of life). Management follows a stepped approach: (1) Lifestyle—sustained caloric deficit (typically 500–750 kcal/day deficit for ~0.5–1 kg/week weight loss, considered safe and sustainable), increased physical activity (150 minutes/week moderate-intensity aerobic exercise), and behavioral modification (self-monitoring, stress management, sleep hygiene, support groups). This is first-line and should be offered to all. (2) Pharmacotherapy—for selected patients (BMI ≥30 or ≥27 with comorbidities) who have failed or plateaued on lifestyle measures: orlistat (a pancreatic/gastric lipase inhibitor reducing fat absorption by 30%, with GI side effects); GLP-1 receptor agonists such as liraglutide or semaglutide (which enhance satiety and reduce appetite, with evidence of cardiovascular benefit); other agents under investigation. (3) Bariatric surgery—for severe obesity (BMI ≥40 or ≥35 with significant comorbidity) unresponsive to conservative measures. Nursing role: assess readiness for change, set realistic goals (weight loss ≥5% reduces cardiometabolic risk; very slow loss is more sustainable than crash dieting), screen for comorbidities (blood pressure, fasting glucose, lipid panel, sleep apnea symptoms), provide non-judgmental, weight-inclusive care (stigma reduces health-seeking and worsens outcomes), and coordinate interdisciplinary management (nutritionist, physician, mental health provider if indicated).

Bariatric surgery is definitive treatment for severe obesity (typically BMI ≥40, or ≥35 with comorbidities like diabetes, sleep apnea, or cardiovascular disease) when lifestyle and medical measures have failed. Common procedures: (1) Sleeve gastrectomy—vertical removal of ~75% of the stomach, reducing capacity to ~150 mL; preserves the pyloric sphincter and small-bowel anatomy. (2) Roux-en-Y gastric bypass—creation of a small gastric pouch (~20–30 mL) connected directly to the jejunum, bypassing the distal stomach and duodenum; induces early satiety and reduced nutrient absorption. (3) Adjustable gastric banding (less common now)—a silicone band placed around the proximal stomach, limiting intake. (4) Biliopancreatic diversion—more complex, combining gastric reduction with partial intestinal bypass; reserved for very severe obesity. Weight loss results from reduced caloric intake (mechanical restriction), altered satiety signals (from GLP-1 and other hormonal changes), and (in bypass procedures) reduced calorie absorption. Weight loss is typically 50–70% of excess body weight over 1–2 years. Post-operative nursing priorities: (1) Monitor for anastomotic leak—separation of the surgical anastomosis (junction between the gastric pouch and jejunum in bypass, or the gastric sleeve edge) leading to peritoneal contamination. Early signs (within 24–48 hours) include tachycardia, fever, severe abdominal pain that is out of proportion to exam findings, restlessness, and hemodynamic instability. This is an emergency requiring immediate surgical intervention. (2) Maintain small frequent feeds progressing per protocol (clear liquids → full liquids → puree → soft solid over weeks to months), avoiding stretching the small pouch. (3) Prevent venous thromboembolism (VTE) with early ambulation, mechanical prophylaxis, and pharmacologic prophylaxis if indicated (many obese patients have additional VTE risk factors). (4) Manage comorbidities—many obese patients have hypertension, sleep apnea, and diabetes; continue monitoring and medication adjustment as weight decreases. (5) Support the airway—obese patients with sleep apnea are at high risk for post-operative respiratory compromise; oxygen therapy, positioning, and close monitoring are essential. Complications: anastomotic leak (as above), acute pancreatitis, bowel obstruction, internal herniation, VTE, and dumping syndrome (see below). Dumping syndrome occurs in 10–15% of bypass patients and manifests as cramping, diarrhea, tachycardia, palpitations, sweating, tremor, flushing, and dizziness 15–30 minutes after eating (early dumping) or 1–3 hours after (late dumping from reactive hypoglycemia). Pathophysiology: rapid gastric emptying of hyperosmolar chyme into the small intestine triggers fluid shifts into the bowel lumen (osmotic diarrhea) and sympathetic activation; late dumping results from rapid glucose absorption and insulin-induced hypoglycemia. Prevention: small frequent meals (¼–½ cup per sitting), limit simple carbohydrates and concentrated sweets, increase protein and fat (slower to empty), drink fluids only between meals (not with food to avoid volume distension), and lie down 30 minutes after eating (delays gastric emptying). Severe dumping may require acarbose (α-glucosidase inhibitor slowing carbohydrate absorption) or octreotide (somatostatin analog reducing GI motility). Lifelong nutritional monitoring and supplementation: bypass and banding procedures reduce nutrient absorption and stomach capacity, increasing risk of deficiencies in iron, vitamin B12, folate, calcium, vitamin D, and thiamine (especially if vomiting occurs). Patients must take lifelong oral supplements (iron, B12 injections or sublingual, folate, vitamin D, calcium citrate, thiamine, and a multivitamin). Failure to supplement results in microcytic or macrocytic anemia, neuropathy, osteomalacia, tetany, and Wernicke encephalopathy. Sleeve gastrectomy reduces absorption risk somewhat but still requires supplementation.

Micronutrient deficiencies arise from malnutrition, malabsorption (celiac disease, Crohn's disease, short-bowel syndrome, bariatric surgery), chronic diarrhea, or inadequate supplementation. Key deficiencies and their manifestations: (1) Iron deficiency—microcytic, hypochromic anemia; fatigue; dyspnea on exertion; pallor; glossitis (inflamed tongue); koilonychia (spoon-shaped nails); increased infection risk. Women of childbearing age and those with chronic blood loss (GI bleeding, heavy menstruation) are at high risk. (2) Vitamin B12 (cobalamin) deficiency—from pernicious anemia (autoimmune intrinsic factor loss), dietary insufficiency (vegans), terminal ileum disease/resection, or metformin use. Results in macrocytic anemia and potentially irreversible neurologic damage: paresthesia, ataxia (loss of coordination), dementia, and subacute combined degeneration of the spinal cord. B12 is stored in the liver (2–5 year supply), so deficiency develops slowly. (3) Folate deficiency—from poor dietary intake, malabsorption, or increased demand (pregnancy, hemolysis); causes macrocytic anemia, glossitis, and neural tube defect risk in pregnancy. Unlike B12, folate stores are limited (~3 months), so deficiency emerges quickly with poor intake. (4) Vitamin A deficiency—impairs vision (night blindness is the earliest sign), causes dry skin, increases infection risk, and impairs wound healing. Common in developing regions with malnutrition. (5) Vitamin C (ascorbic acid) deficiency—causes scurvy: poor wound healing, bleeding gums, petechiae, anemia (from impaired iron absorption), and weakness. Develops within weeks of zero intake. (6) Vitamin D and calcium deficiency—impairs bone mineralization, causing bone pain, osteomalacia (soft bones), increased fracture risk, muscle weakness, hypocalcemia with tetany and seizures, and secondary hyperparathyroidism. Filipinos have high vitamin D deficiency rates due to limited sun exposure (particularly in urban areas), dietary insufficiency, and darker skin pigmentation in tropical climates. (7) Thiamine (vitamin B1) deficiency—from alcoholism, diarrhea, or refeeding syndrome; causes Wernicke encephalopathy (confusion, ophthalmoplegia, ataxia—a medical emergency) and wet beriberi (high-output cardiac failure). Thiamine is rapidly depleted when carbohydrates are metabolized and must be supplemented before/with feeding in at-risk patients. (8) Zinc deficiency—slows wound healing, impairs taste and smell (hypogeusia, hyposmia), causes dermatitis (perioral and perianal), alopecia, diarrhea, and immunosuppression. At-risk populations: bariatric surgery patients, chronic diarrhea, parenteral nutrition, and elderly with poor intake.

The nursing process and NANDA-I taxonomy guide care planning for patients with nutritional/metabolic concerns. Common diagnoses include: (1) Imbalanced nutrition: less than body requirements—related to inadequate oral intake (dysphagia, anorexia, NPO status), increased metabolic demand (fever, wound healing, critical illness), or malabsorption. Priority interventions: assess appetite and barriers; encourage small frequent nutrient-dense meals; administer oral supplements; place on NPO appropriately; refer to dietitian; monitor weight and lab markers; prepare for enteral/parenteral nutrition if oral intake fails. (2) Imbalanced nutrition: more than body requirements—related to excessive caloric intake, sedentary lifestyle, or metabolic dysfunction. Interventions: assess eating patterns and triggers; teach portion control and healthy food choices; encourage physical activity; provide behavioral support; monitor weight and comorbidities; consider pharmacotherapy or surgery if indicated. (3) Risk for refeeding syndrome—applies to patients with severe malnutrition or starvation about to receive nutrition. Interventions: identify at-risk patients; give thiamine before feeding; start feeds at 50% of estimated needs; advance gradually; monitor electrolytes closely; replace phosphate, potassium, magnesium aggressively; watch for signs of organ dysfunction. (4) Aspiration risk—related to impaired swallowing, artificial airway, depressed consciousness, or gastroesophageal reflux. Interventions: assess swallowing; position HOB elevated; slow feeding rate; verify tube placement; assess gastric residual; teach patient to report cough/fever. (5) Ineffective airway clearance (related to aspiration)—manifests as cough, dyspnea, crackles, hypoxia. Interventions: suction airway; oxygen therapy; monitor respiratory status; notify physician; consider chest imaging. (6) Infection risk (related to central line for TPN or enteral tube)—Interventions: strict aseptic technique during line/tube care; assess for fever, leukocytosis, positive cultures; maintain catheter integrity; appropriate tubing/dressing changes; educate patient on signs of infection. Prioritization using Maslow's hierarchy: physiologic needs (nutrition, breathing—address aspiration risk and airway patency first) supersede safety (infection prevention through aseptic technique) and love/belonging (social support for adherence). In the Philippine healthcare context (often resource-limited), nurses must prioritize interventions based on available resources while advocating for optimal care.

Nutritional assessment (anthropometrics, biochemical, clinical) determines the severity and type of malnutrition. Mild PEM may respond to oral supplementation and dietary counseling; moderate malnutrition requires enteral feeding; severe malnutrition with non-functional GI tract necessitates TPN. Additionally, assessment of at-risk patients (BMI <16, minimal intake >10 days) triggers refeeding syndrome prevention protocols. This hierarchical approach prevents both under-treatment and over-aggressive feeding that could cause harm.

The gut's ability to function determines feeding route. If the patient can swallow safely and has some gastric/intestinal function, oral or enteral feeding is preferred (fewer infections, preserves gut barrier). When the gut is non-functional (ileus, fistula, severe pancreatitis, bowel resection), TPN bridges the gap. This hierarchy minimizes complications and cost while optimizing recovery. As the GI tract heals, nutrition support is stepped back down (TPN → enteral → oral).

Severe, prolonged malnutrition depletes intracellular phosphate, potassium, and magnesium and exhausts thiamine stores. Upon re-feeding, insulin-driven intracellular electrolyte uptake causes dangerous extracellular hypoelectrolytemia and thiamine deficiency. This relationship defines prevention: identify malnutrition, start feeding slowly and low, give thiamine, and monitor electrolytes closely. Failure to recognize this relationship results in preventable deaths.

Risk of aspiration (from impaired swallowing, gastroesophageal reflux, or improper tube placement) is mitigated by confirming the tube is in the stomach (pH ≤5.5, X-ray) and elevating the head of bed 30–45°. Gravity enhances gastric emptying and reduces reflux into the esophagus and pharynx. Regular assessment of gastric residual volume and slow feeding rates further reduce risk. Understanding this relationship guides preventive interventions.

High-concentration TPN delivers ~250–300 g dextrose daily (equivalent to ~1000 kcal), triggering sustained pancreatic insulin secretion. If TPN is suddenly discontinued, the glucose load drops but insulin secretion lags, causing relative hyperinsulinemia and dangerous hypoglycemia. Tapering TPN and using D10W as a bridge allows insulin secretion to adjust gradually. This relationship explains the cardinal safety rule: never stop TPN abruptly.

Obesity increases risk of diabetes, hypertension, dyslipidemia, and sleep apnea. After bariatric surgery, weight loss reverses these conditions (blood pressure drops, glucose improves, lipids normalize), but patients are at risk for post-operative complications (anastomotic leak, dumping syndrome) and nutritional deficiencies. This relationship requires comprehensive post-operative monitoring, medication adjustments as weight decreases, and lifelong supplementation. Nurses must coordinate multiple aspects of care.

Polymeric formulas (intact nutrients) have normal osmolality (~300 mOsm/L) and are well-tolerated in a functioning GI tract. Elemental/semi-elemental formulas (hydrolyzed) have higher osmolality and may cause cramping/diarrhea if infused too rapidly but are necessary in impaired absorption (pancreatitis, short-bowel). Disease-specific formulas adjust electrolytes and macronutrient ratios for renal failure, hepatic encephalopathy, or diabetes. Selection must match the patient's absorptive capacity; inappropriate formula selection causes intolerance and feeding failure.

TPN's hyperosmolar glucose and lipid composition create an ideal growth medium for bacteria and fungi. The central line provides direct vascular access, making infection entry possible. Strict aseptic technique during placement, tubing changes, and site care, combined with regular dressing and tubing changes, reduces CRBSI incidence. Nurses are responsible for this infection prevention; failure results in sepsis, septic shock, and catheter removal. Understanding this causal chain emphasizes the importance of meticulous technique.

Gastric bypass and restrictive procedures reduce stomach capacity and nutrient absorption (iron, B12, folate, calcium, vitamin D, thiamine). Without lifelong supplementation, deficiency develops over months to years, causing anemia, neuropathy, osteomalacia, and neurologic damage. This relationship mandates patient education at discharge and long-term follow-up. Many bariatric patients fail to take supplements due to cost, compliance, or lack of understanding of their necessity; nurses must reinforce this repeatedly.