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Total Parenteral Nutrition


Total Parenteral Nutrition

Article Author:
Marah Hamdan
Article Editor:
Yana Puckett
Updated:
6/28/2020 9:40:49 PM
For CME on this topic:
Total Parenteral Nutrition CME
PubMed Link:
Total Parenteral Nutrition

Indications

Parenteral nutrition is the intravenous administration of nutrition outside of the gastrointestinal tract. Total parenteral nutrition (TPN) is when the IV administered nutrition is the only source of nutrition the patient is receiving. Total parenteral nutrition is indicated when there is an inadequate gastrointestinal function and contraindications to enteral nutrition. Enteral diet intake is preferred over parenteral as it is inexpensive and associated with fewer complications such as infection and blood clots but requires a functional GI system.[1]
According to Chowdary and Reddy (2010), TPN indications include [2]:

  • Chronic intestinal obstruction as in intestinal cancer [3]
  • Bowel pseudo-obstruction with food intolerance. 
  • TPN can also be used to rest the bowel in cases of GI fistulas with high flow [4]
  • When an infant’s gastrointestinal system is immature or has a congenital gastrointestinal malformation
  • When there is a post-operative bowel anastomosis leak
  • When the patient is unable to maintain nutritional status due to severe diarrhea or vomiting
  • Small bowel obstruction
  • Hypercatabolic states due to sepsis, polytrauma, and major fractures [5]
  • An anticipated period of nothing by mouth (NPO) status greater than seven days as in patients with inflammatory bowel disease exacerbations as well as critically ill patients [6]

Mechanism of Action

TPN is a mixture of separate components which contain lipid emulsions, dextrose, amino acids, vitamins, electrolytes, minerals, and trace elements.[7][8] TPN composition should be adjusted to fulfill individual patients' needs. The main three macronutrients are lipids emulsions, proteins, and dextrose. 

Lipid emulsions:

  • It provides calories and prevents fatty acid deficiency. Essential fatty acid deficiency may develop within three weeks of fat-free TPN.[2]
  • 25% to 30% of the total calories are in the form of lipids.

Proteins:

  • A solution that contains essential and non-essential amino acids except arginine and glutamine
    • Healthy adult requirements are 0.8 to 1 gm of protein/kg/day.
  • This change based on the condition of the patient. Critically ill patients require 1.5 gm/kg/day, patients with chronic renal failure are given 0.6 to .0.8 gm/kg/day, and patients with acute hepatic encephalopathy need temporary protein restriction to 0.8 gm/kg/day, patients on hemodialysis need 1.2 to 1.3 gm/kg/day.[2]

Carbohydrate:

  • Provided through dextrose monohydrate in a variety of concentrations, most commonly 40,50, and 70%
  • Glucose utilization maximum rate is 5 to 7 mg/kg/min.
  • Excess carbohydrate supplementation can result in hyperglycemia and hypertriglyceridemia.

Electrolytes, trace elements, and vitamins are micro-nutrients.

  • Trace elements and vitamins dosing can be according to recommended daily requirements.
  • Electrolytes recommendation per liter of parenteral nutrition:
    • Sodium: 100 to 150 mEq
    • Magnesium: 8 to 24 mEq
    • Calcium: 10 to 20 mEq
    • Potassium: 50 to 100 mEq
    • Phosphorus: 15 to 30 mEq

Total nutrition is an admixture, a 3-in-1 solution of the three macronutrients (dextrose, amino acids, lipid emulsions).

  • A 3-in-1 solution and intravenous lipid emulsions) mixed with electrolytes, trace elements, vitamins, and water. Parenteral solution with only dextrose and amino acids with a separate intravenous lipid emulsions infusion, the 2-in-1 solution has also been previously used.[7] Research has shown TNA to be the standard of care for adult TPN.

Currently used TPN amino acid mixture continues to be incomplete with only 19 amino acids.[9] The non-essential amino acid glutamine has been used as a complement to TPN to complete the amino acid content of TPN (Glutamine 8 to 10% in PN is a compliment). Surgical critical care patients have decreased glutamine levels on admission, which continues to decline until the third hospital ICU day. Per a study by Tsuji, both high ≥700 nmol/mL and low  <400 nmol/mL of glutamine levels in ICU patients showed a statistical correlation with increased mortality than those patients with a range between 400 to 700 nmol/mL.[10] Glutamine should serve as a complement to TPN rather than pharmaco-nutrition at supra nutritional doses. Patients who should not receive glutamine complementation above what may be present in basal TPN, as referenced by Heyland et al., include patients in septic shock, hemodynamic instability with increased vasopressor doses, patients with renal failure.[11]

Administration

Total parenteral nutrition administration is through a central venous catheter. A central venous catheter is an access device that terminates in the superior vena cava or the right atrium and is used to administer nutrition, medication, chemotherapy, etc. Establishing this access could be through a peripheral inserted central catheter (PICC), central venous catheter, or an implanted port.[12]

PICC line insertion can be through the basilic, cephalic, brachial, or median cubital vein of the arm. The basilic vein is preferable due to its larger size and superficial location. The catheter courses through the basilic into the axillary vein, to the subclavian vein, to settle in the superior vena cava.[13] PICC lines could be used when TPN is administered for several weeks to months.

The insertion of central venous catheters can be through one of the large three central veins: femoral vein, subclavian vein, and internal jugular vein. Central venous catheters are used when administering TPN for several months to years.[14]

An implanted port is a device that is implanted under the skin in the chest with an attached catheter inserted into the superior vena cava. Implantable ports are used when administering TPN for years.[14]

Total parenteral nutrition is not administered through a peripheral intravenous catheter (Peripheral Parenteral Nutrition, PPN) because it has high osmolarity. PPN osmolarity needs to be less than 900 mOsm. The lower concentration necessitates larger volume feedings, and high-fat content is necessary. High osmolarity irritates peripheral veins; hence TPN is given through central venous access. PPN is used to provide additional nutrition to patients with functional gut and enteral feedings.

Adverse Effects

The main adverse effects can be due to metabolic abnormalities, infection risk, or venous access associated.

Venous access: It is associated with the insertion of the central line catheter. 

  • Pneumothorax
  • Air embolism
  • Bleeding
  • Venous thrombosis
  • Vascular injury [15][2]

Catheter site infections:

  • Bloodstream infection, known as sepsis
  • Local skin infection at insertion or exit site

Metabolic abnormalities:

  • Refeeding syndrome in chronic alcoholic patients, and in patients who have nothing-by-mouth status (NPO) for more than 7 to 10 days
  • Hyperglycemia
  • Sudden discontinuation can lead to hypoglycemia. Hypoglycemia is correctable with 50% dextrose. 
  • Serum electrolyte abnormalities
  • Wernicke’s encephalopathy [16][2]
  • Parenteral associated cholestasis cholestasis

Contraindications

According to Maudar (2017), TPN is generally contraindicated in the following conditions:

  • Infants with less than 8 cm of the small bowel
  • Irreversibly decerebrate patients
  • Patients with critical cardiovascular instability or metabolic instabilities. Such instabilities require correction before administering intravenous nutrition. 
  • When gastrointestinal feeding is possible
  • When the nutritional status is good and, only short-term TPN is needed
  • The lack of a therapeutic goal, as TPN should not be used to prolong life when death is unescapable.[5]

Monitoring

Per Maudar 2017, several variables require monitoring while on TPN[5]:

  • Intake and output 12-hour charts
  • Urine sugar estimate every 8 hours
  • Serum electrolytes: daily sodium, potassium, bicarbonate, calcium, and chloride values
  • Serum creatinine and blood urea daily values
  • Serum protein levels twice daily
  • Liver function tests twice daily


The American Society for Parenteral and Enteral Nutrition (ASPEN) guidelines include[17]:

  • Patients who recently received TPN should be monitored daily until stable. They require more frequent monitoring if metabolic abnormalities are detected or if the patient has a risk of refeeding syndrome. Refeeding syndrome can occur in severely malnourished and cachectic individuals when feeding is reintroduced and can lead to severe electrolyte instabilities. Refeeding syndrome can correlate with hypophosphatemia, respiratory distress, rhabdomyolysis, and acute kidney injury. Prevention of refeeding syndrome is critical and achievable with a slower initial infusion of TPN than would be exected.[18]
  • Unstable and critically ill patients should be monitored daily until stable.
  • Stable hospital patients with no formulation changes for one week should be monitored every 2 to 7 days.
  • Stable hospital, home, or long-term care setting patients with no formulation changes for one week should be monitored every 1 to 4 weeks if clinically stable.

Toxicity

Generally, the toxicity of TPN is related to the individual toxicity of its components. Increased caloric amounts due to TPN glucose and lipid excess can lead to hepatic toxicity; this risk can decrease by using decreased glucose content and greater lipid content. A glucose infusion rate greater than 5 mg/Kg/min can result in fatty liver; this is because increase glucose in the blood induces hepatic lipogenesis, and increased glucose levels trigger increased insulin levels leading to more lipogenesis.[19] This effect is preventable by decreased dextrose dosage to under 5 g/kg day, less than 5mg/kg min, cyclic PN for 8 hours as it decreases hyper-insulin, and substituting 30% of dextrose energy with lipids.

Parenteral nutrition supplementation rather than total parenteral nutrition is harmful to pediatric patients in the pediatric intensive care unit (PICU). Parenteral nutrition supplementation should be withheld in the first week in the PICU independent of age or nutritional status; this is because amino acids in the PN suppress the autophagy process needed for cellular damage removal. Excess amino acids a shuttled to urea production. Increased urea levels can pose harm to the kidney and liver.[20]

Long term usage of TPN ranging from weeks to months can be associated with the rare complication of manganese toxicity. Manganese exposure via TPN is characterized by high bioavailability due to bypassing the GI tract regulatory mechanisms. This high concentration of manganese over time leads to its deposition in the liver, brain, and bone. However, the brain is most likely to be affected as manganese will deposit and affect the globus pallidus and striatum of the basal ganglia. Manganese preferentially affects dopaminergic neurons in the basal ganglia resulting in extrapyramidal symptoms that present in a similar way to  Parkinson disease. Idiopathic Parkinson disease can be differentiated based on the location of neurons affected, i.e., in the substantia nigra.[21]

Enhancing Healthcare Team Outcomes

Managing the administration of TPN need s a well-coordinated health care team with an interprofessional approach.

The team includes:

  • Clinician
  • Pharmacist
  • Dietician
  • Nutrition nurse specialist

The clinician determines the treatment and the form of needed nutrition. The clinician coordinates care with the patient's primary health care team.

The pharmacist provides sterile parenteral nutrition. The pharmacists' advice on the stability of the compound and any drug/nutrient interactions that may arise.

The dietician assesses the nutritional status of the patient, calculates the daily requirement, and designs the feeding regiment.

The nutrition nurse specialist supervises catheters and tube care. They are the patient's advocate and trains the patient/caretaker to manage the tubes at home.

Extended staff includes: social workers, occupational therapists, and wound management nurses.[22]


References

[1] Braunschweig C,Liang H,Sheean P, Indications for administration of parenteral nutrition in adults. Nutrition in clinical practice : official publication of the American Society for Parenteral and Enteral Nutrition. 2004 Jun;     [PubMed PMID: 16215113]
[2] Chowdary KV,Reddy PN, Parenteral nutrition: Revisited. Indian journal of anaesthesia. 2010 Mar;     [PubMed PMID: 20661345]
[3] Weimann A,Ebener Ch,Holland-Cunz S,Jauch KW,Hausser L,Kemen M,Kraehenbuehl L,Kuse ER,Laengle F, Surgery and transplantation - Guidelines on Parenteral Nutrition, Chapter 18. German medical science : GMS e-journal. 2009 Nov 18;     [PubMed PMID: 20049072]
[4] Messing B, [Parenteral nutrition: indications and techniques]. Annales de medecine interne. 2000 Dec;     [PubMed PMID: 11173709]
[5] Maudar KK, TOTAL PARENTERAL NUTRITION. Medical journal, Armed Forces India. 1995 Apr;     [PubMed PMID: 28769264]
[6] Gotthardt DN,Gauss A,Zech U,Mehrabi A,Weiss KH,Sauer P,Stremmel W,Büchler MW,Schemmer P, Indications for intestinal transplantation: recognizing the scope and limits of total parenteral nutrition. Clinical transplantation. 2013 Jul-Aug;     [PubMed PMID: 23909502]
[7] Slattery E,Rumore MM,Douglas JS,Seres DS, 3-in-1 vs 2-in-1 parenteral nutrition in adults: a review. Nutrition in clinical practice : official publication of the American Society for Parenteral and Enteral Nutrition. 2014 Oct;     [PubMed PMID: 25606645]
[8] Mohandas KM,Shastri YM,Shirodkar M, Total parenteral nutrition. The National medical journal of India. 2003 Jan-Feb;     [PubMed PMID: 12715955]
[9] Wischmeyer PE, The glutamine debate in surgery and critical care. Current opinion in critical care. 2019 Aug     [PubMed PMID: 31247630]
[10] Tsujimoto T,Shimizu K,Hata N,Takagi T,Uejima E,Ogura H,Wasa M,Shimazu T, Both high and low plasma glutamine levels predict mortality in critically ill patients. Surgery today. 2017 Nov     [PubMed PMID: 28374265]
[11] Heyland D,Muscedere J,Wischmeyer PE,Cook D,Jones G,Albert M,Elke G,Berger MM,Day AG, A randomized trial of glutamine and antioxidants in critically ill patients. The New England journal of medicine. 2013 Apr 18     [PubMed PMID: 23594003]
[12] Kovacevich DS,Corrigan M,Ross VM,McKeever L,Hall AM,Braunschweig C, American Society for Parenteral and Enteral Nutrition Guidelines for the Selection and Care of Central Venous Access Devices for Adult Home Parenteral Nutrition Administration. JPEN. Journal of parenteral and enteral nutrition. 2019 Jan;     [PubMed PMID: 30339287]
[13] Gonzalez R,Cassaro S, Percutaneous Central Catheter (PICC) 2019 Jan;     [PubMed PMID: 29083596]
[14] Leib AD,England BS,Kiel J, Central Line 2019 Jan;     [PubMed PMID: 30137796]
[15] Parienti JJ,Mongardon N,Mégarbane B,Mira JP,Kalfon P,Gros A,Marqué S,Thuong M,Pottier V,Ramakers M,Savary B,Seguin A,Valette X,Terzi N,Sauneuf B,Cattoir V,Mermel LA,du Cheyron D, Intravascular Complications of Central Venous Catheterization by Insertion Site. The New England journal of medicine. 2015 Sep 24;     [PubMed PMID: 26398070]
[16] Mattioli S,Miglioli M,Montagna P,Lerro MF,Pilotti V,Gozzetti G, Wernicke's encephalopathy during total parenteral nutrition: observation in one case. JPEN. Journal of parenteral and enteral nutrition. 1988 Nov-Dec;     [PubMed PMID: 3148047]
[17] Ayers P,Adams S,Boullata J,Gervasio J,Holcombe B,Kraft MD,Marshall N,Neal A,Sacks G,Seres DS,Worthington P, A.S.P.E.N. parenteral nutrition safety consensus recommendations. JPEN. Journal of parenteral and enteral nutrition. 2014 Mar-Apr;     [PubMed PMID: 24280129]
[18] Lakananurak N,Gramlich L, The Role of Preoperative Parenteral Nutrition. Nutrients. 2020 May 6     [PubMed PMID: 32384662]
[19] Guglielmi FW,Boggio-Bertinet D,Federico A,Forte GB,Guglielmi A,Loguercio C,Mazzuoli S,Merli M,Palmo A,Panella C,Pironi L,Francavilla A, Total parenteral nutrition-related gastroenterological complications. Digestive and liver disease : official journal of the Italian Society of Gastroenterology and the Italian Association for the Study of the Liver. 2006 Sep;     [PubMed PMID: 16766237]
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