TOTAL PARENTERAL NUTRITION (TPN)

·         Supply all daily nutritional requirements parenterally (i.v. only)

·         Indications- (either disorders causing complete bowel rest/presence of non-functioning GI tract)

o   Enterocutaneous fistulas

o   Short Bowel Syndrome

o   Intestinal obstruction

o   Prolonged ileus

o   Refractory chronic intestinal pseudo-obstruction (refractory Ogilvie syndrome)

o   Some non-responding cases of chylous ascites

o   Some stages of Crohn's disease or ulcerative colitis

o   In Pediatric GI disorder- congenital GI anomalies, prolonged diarrhea regardless of its cause

·         Solutions types- (variation are done in certain co-morbid conditions)

o   Renal/Liver insufficiency -

§  ↓protein but ↑ free essential amino acids containing TPN

o   Cardiac/Renal failure-

§  Limited volume TPN intake

o   Respiratory failure-

§  Lipid emulsion- because fat releases more amount of energy/CO₂ molecule generated than carbohydrate.

o   Neonates- ↓dextrose concentration (17-18%)

·         Monitoring- following need to be monitored-

o   Weight

o   Complete Blood Count

o   Glucose

o   Liver function tests

o   BUN & Serum electrolytes

o   Plasma proteins (serum albumin, transthyretin)

o   Nutritional assessment

·         Complications

o   Glucose abnormalities- (>90% cases)

§  Hyperglycemia- prevented by monitoring glucose levels & adjusting insulin dosage accordingly in TPN

§  Hypoglycemia-

·         degree of hypoglycemia dictates the treatment.

·         i.v. Dextrose solution is used.

o   Hepatic complications- (>90% cases)

§  Liver dysfunction (↑liver enzymes & bilirubin)- due to TPN/ ↑circulating amino acids resulting from ↑ protein in TPN

§  Painful Hepatomegaly-

·         Due to accumulation of fat

·         Avoided by ↓carbohydrate in TPN

§  Hyperammonemia-

·         Infants more susceptible

·         Lethargy, twitching & generalized seizures

·         Rx- Arginine supplementation

§  Liver Failure-

·         Transplantation required

o   Catheter related sepsis (>50%)

o   Volume overload (due to ↑ energy requirements thus requiring more TPN)

o   Serum electrolyte abnormalities & kidney dysfunction- (↑BUN)

o   Metabolic Bone Disease- Osteoporosis/Osteomalacia (in prolonged TPN)

§  Severe pain in periarticular region/lower extremity/back

§  Rx- permanently stop TPN

o   Gall Bladder complications-

§  Prolonged gallbladder stasis leads to gallbladder sludge formation, cholelithiasis & cholecystitis.

§  Metronidazole/cholecystokinin/ursodeoxycholic acid maybe required.

o   Venous thrombosis-

§  Since TPN solutions are concentrated, therefore they have a potential to cause venous thrombosis.

§  If TPN delivered via peripheral veins, then risk of peripheral venous thrombosis ↑↑, therefore, a central venous catheter preferred.

o   Nutritional deficiencies-

§  Virtually, any nutrient deficiency may develop.

§  Fat-soluble vitamins, folate, Vit B₁₂, calcium, iron, magnesium, and zinc require monitoring as they are critical substances.

o   Adverse reactions due to lipid component-

§  Early- allergic reactions

§  Late- liver dysfunction, splenomegaly, leucopenia, thrombocytopenia.