When a client cannot eat enough by mouth, nutrition is given by tube into the gut (enteral nutrition) or into a vein (parenteral nutrition). The rule is "if the gut works, use it": enteral feeding maintains the intestinal barrier and immune function, costs less, and causes fewer infections than parenteral nutrition.

Enteral access

Parenteral nutrition (PN)

• Given when the GI tract cannot be used or cannot meet needs: bowel obstruction, prolonged ileus, severe short bowel syndrome, high-output fistula, severe malabsorption
• Central PN is hypertonic and must go through a central venous catheter (including a PICC) with the tip in the superior vena cava
• Peripheral PN is limited to lower osmolarity (about 900 mOsm/L or less) and short-term use

Refeeding syndrome — when feeding restarts after starvation, insulin release drives phosphate, potassium, and magnesium into cells. Severe hypophosphatemia can cause muscle weakness, respiratory failure, heart failure, dysrhythmias, and death. Thiamine deficiency may be unmasked. High-risk clients include those with very low BMI, little intake for more than 5–10 days, alcohol use disorder, and significant recent weight loss. The risk applies to enteral and oral refeeding as well as PN. In high-risk clients, start at about 10–20 kcal/kg/day (or 100–150 g dextrose) for the first 24 hours and advance slowly, give thiamine 100 mg before feeding and daily for 5–7 days, and check potassium, magnesium, and phosphate every 12 hours for the first 3 days, replacing as ordered.

Before feeding

• Tube position (see Diagnostics); external tube length at the nares or skin level compared with the documented mark
• Abdomen: distension, firmness, bowel sounds, flatus, pain
• Nausea, vomiting, stool pattern
• Head-of-bed elevation, level of consciousness, cough and gag reflex

During feeding

• Tolerance: abdominal distension, cramping, nausea, vomiting, diarrhea
• Aspiration: coughing, dyspnea, falling SpO₂, new crackles, fever
• Fluid status: daily weight, intake and output, edema
• Blood glucose (enteral and especially parenteral nutrition)
• Skin at the nares or stoma site: redness, drainage, pressure, leakage

Verifying feeding tube placement

• Radiograph (X-ray) confirmation is required after blind insertion of a small-bore feeding tube and before the first feeding or medication — it is the only reliable method.
• Auscultation of injected air is not a reliable method — air injected into a tube in the lung or esophagus can sound the same as air in the stomach. Do not use it to confirm placement.
• Bubbling in water and the client's ability to speak are also unreliable.
• After X-ray confirmation, mark the tube's exit point and check position before each feeding or medication and at least every 4 hours during continuous feeding using:
  • The external length compared with the documented mark
  • Aspirate pH — gastric fluid usually has a pH of 5 or less (higher with acid-suppressing drugs or continuous feeding); a pH above 6 may indicate intestinal or respiratory placement
  • Aspirate appearance (gastric: grassy green, clear, or tan)
• If there is any doubt — coughing, respiratory distress, change in external length, or unexpected aspirate — stop and obtain an X-ray.
• Capnography or a colorimetric CO₂ detector during insertion can detect airway entry, but it does not replace X-ray confirmation.

Monitoring labs: electrolytes, phosphate, magnesium, glucose, BUN, creatinine, liver function tests, triglycerides (with lipid emulsions), prealbumin and CRP trends, and weight.

Enteral formulas and methods

Gastric residual volume (GRV): routine GRV checks are no longer recommended by US critical care nutrition guidelines because they do not reliably predict aspiration and cause unnecessary interruptions. Where facility policy still uses GRV, feeding is not held for GRV below 500 mL unless there are other signs of intolerance (vomiting, distension). Return aspirate to the stomach per policy. Older textbook cutoffs of 100–250 mL are outdated.

Parenteral nutrition

• Dextrose, amino acids, lipid emulsion, electrolytes, vitamins, and trace elements, prepared by pharmacy for each client
• Started slowly and advanced to goal, following the refeeding precautions above
• Hyperglycemia is common — treat with insulin (often added to the PN bag or by sliding scale); common hospital target 140–180 mg/dL (7.8–10.0 mmol/L)

Drug safety

Enteral feeding — priority actions

1. Prevent aspiration: keep the head of the bed at 30–45° during feeding and for 30–60 minutes after intermittent or bolus feeds (unless contraindicated); stop the feeding before lying the client flat. If the client vomits, stop the feeding and turn the client to the side to protect the airway, then suction as needed and notify the provider.
2. Confirm tube position before every use (see Diagnostics).
3. NG tube insertion (competency and policy dependent): high-Fowler's position; measure nose to earlobe to xiphoid (NEX) and mark; lubricate with water-soluble lubricant; ask the client to flex the head forward (chin to chest) and swallow as the tube passes the pharynx; stop if coughing, cyanosis, or inability to speak occurs; secure the tube and obtain the X-ray.
4. Flush the tube with 30 mL water every 4 hours during continuous feeding and before and after intermittent feeds and medications (sterile water in immunocompromised or critically ill clients, per policy) to prevent clogging.
5. Formula handling: give at room temperature (cold formula causes cramping); check the expiration date; open-system formula should hang no longer than about 8 hours (4 hours for reconstituted powder or neonatal feeds); closed ready-to-hang systems up to 24–48 hours per manufacturer; change administration sets per policy.
6. Diarrhea: check the rate and concentration, but also look for medications (antibiotics, sorbitol-containing liquid drugs, magnesium, laxatives) and Clostridioides difficile infection. Slowing the rate or changing to a fiber-containing formula may help; do not stop feeding automatically.
7. Oral and nasal care at least every 4 hours or per policy: tube-fed clients produce less saliva and have more oral bacteria, which increases aspiration pneumonia risk.
8. Gastrostomy (PEG) care: clean the site daily with soap and water or saline and dry it; check that the external bumper is not too tight; once the tract is healed, rotate the tube daily if the manufacturer allows, to prevent the internal bumper from embedding. Report leakage, redness, or pain with feeding. If a new tube (tract less than about 4 weeks old) dislodges, cover the site and notify the provider immediately — do not reinsert.

Parenteral nutrition

1. Aseptic central line care: dedicated lumen for PN when possible; do not draw blood from or give other drugs through the PN lumen unless compatibility is confirmed; scrub the hub before access; follow CLABSI bundles.
2. Infuse by pump at the prescribed rate; do not catch up if the infusion falls behind.
3. If PN must stop suddenly or the next bag is unavailable, hang dextrose 10% at the same rate per order to prevent rebound hypoglycemia; taper PN when discontinuing.
4. Check capillary glucose every 4–6 hours initially and as ordered.
5. Filters and tubing: use a 1.2-micron filter for PN containing lipids (total nutrient admixture) and a 0.2-micron filter for dextrose–amino acid solutions; change tubing for lipid-containing PN every 24 hours.
6. Weigh daily; monitor intake and output, electrolytes, phosphate, magnesium, and liver function.
7. Watch for air embolism during line changes or line damage: sudden dyspnea, chest pain, hypotension → clamp the catheter, place the client on the left side with head lowered (if tolerated), give oxygen, and call for help.

• Home enteral feeding: hand hygiene, checking tube position with the external mark, flushing, feeding upright, and what to do if the tube blocks or falls out.
• Do not use cranberry juice or cola to unclog tubes unless the policy allows; warm water with gentle push-pull is first-line.
• Report vomiting, abdominal swelling, persistent diarrhea, fever, or breathing trouble.
• Home PN: line care, pump use, signs of infection (fever, chills), and signs of high or low blood glucose.

• X-ray confirms initial placement of a blindly inserted feeding tube — not air auscultation
• Ongoing checks: external mark length and aspirate pH (≤ 5 suggests gastric) before each use
• Head of bed 30–45° during feeding and 30–60 minutes after intermittent feeds
• Vomiting: stop the feeding and turn the client to the side
• Aspiration pneumonia is the most serious enteral complication
• Continuous feeding has the best GI tolerance
• GRV is no longer routinely required; if used, do not hold for GRV below 500 mL without other signs
• Feeds at room temperature; open-system formula hangs about 8 hours
• Flush 30 mL water every 4 hours and before and after medications; never add drugs to formula
• PEG for long-term feeding (beyond about 4–6 weeks)
• PN: central line, pump, glucose monitoring, never stop abruptly — dextrose 10% if the bag is unavailable
• Refeeding syndrome = hypophosphatemia, hypokalemia, hypomagnesemia; start slowly and give thiamine