Gastroenterology In Critical Care

Nutritional Support In Critical Care

Parenteral Nutritional Support (TPN)

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Parenteral Nutritional Support

INDICATIONS

When the enteral route is contraindicated (GI disorders)

When the enteral route is ineffective (high calorie demands)

ROUTES

Central vein
Peripheral vein

TYPE OF CATHETER

· Short-term: peripheral or central venous catheter
· Long-term: Hickman, Broviac, or Groshong catheter
· If multiple-lumen catheter used, infusion through the distal lumen

SOLUTION
· Hypertonic glucose (peripheral 10%; central 25%)
· Enough calories in carbohydrates (or fats) for maximal protein-sparing effect
· Crystalline amino acids 2.5%-8.5% (essential and nonessential)
· Electrolytes: sodium, chloride, potassium, calcium, magnesium, phosphorus
· Buffer: acetate or bicarbonate
· Minerals: iron, zinc, copper, manganese, chromium, selenium
Multivitamins Multivitamins
· Lipids: 30% of nonprotein calories or at least 4% to 6% of total calories should be provided by linoleic acid to prevent deficiency of
essential fatty acids

POSSIBLE ADDITIONS

Insulin (sliding scale insulin still must be administered as needed)
Heparin
Metoclopramide (Reglan)
H2 receptor antagonists
NOTE: All additives added under laminar hood (in pharmacy department), not on nursing unit

GUIDELINES

- insertion and management under strict sterile technique
- Use of a line that has been previously used for CVP measurements or the prolonged administration of a crystalloid solution or blood products is prohibited
- Port (or lumen) not to be used for drawing blood samples or infusing any other fluids
- Discarding of cloudy solutions
- If hanging 3-in-1 solution (also called total nutrient admixture}, necessary to monitor closely for emulsion crack; solution not to be hung if layer of fat is seen separated at top of bag
- Use of an inline filter necessary
- Starting rate 1200 to 2400 kcal/day and increased to desired caloric intake
- Constant rate (volumetric pump is essential)
- Dressing changes every 48 hours

MONITOR
· Vital signs and infusion rate at least every 4 hours (depending on the acuity of the patient's condition)
· Intake and output
· Weight daily
· Serum glucose q 6 hours
· CBC, electrolytes, calcium, magnesium, phosphorus, BUN, creatinine, total bilirubin, ALT, AST, uric acid, total protein, albumin, plate
count, prothrombin time as indicated
· Catheter site

COMPLICATIONS

· Infection and sepsis = Use strict sterile dressing change technique, Monitor for fever and other signs of infection
· Hyperglycemia = Decrease rate of infusion, Administer insulin therapy, Monitor serum glucose levels
· Hyperosmolar nonketotic dehydration = Provide insulin therapy as indicated, · Administer 5% dextrose and hypotonic saline (0.25-0.45) to correct free water deficit, Discontinue TPN until patient is stable
· Hypoglycemia= This usually occurs with interruption of TPN infusion (e.g., catheter occlusion or accidental removal)
· An infusion pump is mandatory
· TPN should never be discontinued abruptly unless for HHNK
· Electrolyte imbalances: hyperchloremic metabolic acidosis; hypophosphatemia; hyperammonia, hypokalemia, hyponatremia
· The usual treatment is adjustment of TPN solution concentration and/or alteration of infusion rate
· Increased CO, production
· This may cause ventilatory distress or make weaning from mechanical ventilation difficult
· Decrease the percentage of calories supplied by CHO and increase the percentage of calories supplied by fats
· Subclavian thrombosis (rare)
· Remove catheter
· Thrombolytic or anticoagulation therapy may be indicated
· The first sign is swelling of involved arm, face, and neck