Nutrition Therapy and Pathophysiology Past Paper PDF

CHAPTER 5 Source: istock.com/Yobro10 Enteral and Parenteral Nutrition Support Kristen Roberts, PhD, RDN, LD, CNSC Marcia Nahikian-Nelms, PhD, RDN, LD, FAND The Ohio State University LEA RNING O B JE...

CHAPTER 5 Source: istock.com/Yobro10 Enteral and Parenteral Nutrition Support Kristen Roberts, PhD, RDN, LD, CNSC Marcia Nahikian-Nelms, PhD, RDN, LD, FAND The Ohio State University LEA RNING O B JECTIV ES LO 5.1 List consequences of LO 5.6 Explain refeeding syndrome, LO 5.9 Calculate estimated nutrient malnutrition. how it can be avoided, and which needs for parenteral and enteral patients are at highest risk. ­nutrition prescriptions. LO 5.2 Discuss the difference between enteral and parenteral nutrition. LO 5.7 Apply the nutrition care LO 5.10 Determine amounts of process to develop enteral and ­calories and macronutrients provided LO 5.3 Identify disadvantages and parenteral nutrition prescriptions. by ­parenteral and enteral prescriptions. possible complications of enteral and parenteral nutrition. LO 5.8 Explain the steps involved in LO 5.11 Determine criteria for determining the enteral and parenteral ­monitoring and evaluating enteral and LO 5.4 Describe the types of enteral nutrition prescriptions. parenteral feedings. nutrition and their indications. LO 5.5 Describe the three types of enteral feeding delivery methods. 92 GLO SSARY aspiration—inspiration of foreign matter into jejunostomy—an opening into the jejunum peripherally inserted central catheter the lung nasogastric feeding tube—a tube that is (PICC)—vascular access device inserted into bolus feedings—rapid administration of inserted nasally (through the nose) into the the arm and threaded into the subclavian vein 250–500 mL of formula several times daily stomach to the vena cava central venous catheter (CVC)— vascular nasointestinal feeding tube—a tube that propofol—lipid-based drug that is used access device inserted into large veins such as is inserted nasally (through the nose) past the to maintain sedation during mechanical the subclavian, jugular, or femoral veins in the stomach into the intestine ventilation center of the body NPO—nil per os, which is Latin meaning refeeding syndrome—metabolic alterations colonocyte—epithelial cell of the large “nothing by mouth” that may occur during nutritional repletion of ­intestine or colon starved patients orogastric feeding tube—a tube that is continuous feedings—administration of inserted orally (through the mouth) into the specialized nutrition support (SNS)—provi- ­formula for 10–24 hours daily, using a pump stomach sion of nutrients orally, enterally, or parenter- to control the feeding rate ally with therapeutic intent. osmolality—number of water-attracting enteral nutrition (EN)—feeding through the particles per weight of water in kilograms stoma—an opening gastrointestinal tract using a tube, catheter, (expressed as mOsm/kg) structured lipid—commercially produced or stoma that delivers nutrients distal to (or osmolarity—number of millimoles of liquid or lipid that alters fatty acids to allow for beyond) the oral cavity solid in a liter of solution ­absorption as a medium-chain triglyceride gastrostomy—an opening into the stomach ostomy—an artificial opening created by stylet—wire guide within the enteral tube hydrophilic—water loving, or attracting ­surgical procedure that assists with insertion water parenteral nutrition (PN)—administration surgical gastrostomy—an opening into implantable port—vascular access device of nutrition directly into the circulatory system the stomach that requires a surgical that is completely under the skin, is placed (formally known as total parenteral nutrition procedure in the vein on the upper chest wall, and exits [TPN] and intravenous hyperalimentation [IVH], tunneled catheter—intravenous access the body near the xyphoid process, axilla, or which has been replaced by central parenteral device that is placed in the vein on the abdominal wall nutrition [CPN]) upper chest wall and exits the body near intermittent feedings—administration percutaneous endoscopic gastrostomy the xyphoid process, axilla, or abdominal of formula several times daily, over 20–30 (PEG)—a procedure used by a physician to wall minutes insert a feeding tube through the skin and into vascular access device—a device intravenously (IV)—by vein, in reference to the stomach using an endoscope inserted into a vein, which permits administration of drugs or nutrients peripheral parenteral nutrition (PPN)— ­administration of intermittent or continuous intravenous lipid emulsion (ILE)—the type administration of nutrition into a small vein in infusion of ­parenteral solutions of of fat that is administered as part of a paren- the arm or back of the hand (also known as medications teral nutrition solution peripheral venous nutrition [PVN]) viscosity—thickness of a liquid 5.1 INTRODUCTION: PLANNING AND The consequences of inadequate nutrition and subse- quent malnutrition include increased risk of infection, delayed IMPLEMENTATION OF NUTRITION wound healing, and delayed return to home, work, or baseline INTERVENTIONS WITH ENTERAL AND activities of daily living following hospitalization.1,2,5,7–11,12 All PARENTERAL NUTRITION SUPPORT these consequences contribute to increased health care costs With increased focus on the issues of overweight, obesity, and diminished quality of life. Health care institutions—and in and chronic disease in health care, it is important not to lose particular, interdisciplinary clinicians (such as the physician, sight of the fact that insufficient food intake and the result- nurse, registered dietitian nutritionist [RDN], and pharma- ing protein-energy malnutrition are of significant concern. cist)—work to prevent or treat malnutrition and other diseases As many as 30%–50% of hospitalized patients and up to 95% by providing the patient with appropriate specialized nutri- of nursing home patients exhibit some signs of malnutrition. tional support. As discussed in Chapter 4, this support can be Furthermore, almost 70% of hospitalized patients will exhibit provided through an oral diet designed to meet the patient’s a decline in nutritional status during hospitalization and up to specific nutritional requirements and modified to meet his or one-third of these patients will become malnourished.1–4 The her specific physical needs. This might include modification Healthcare Cost and Utilization Project (HCUP) analyzed of the type or amount of food and nutrients within meals or U.S. hospitalizations that involved a diagnosis of malnutrition. at specified times between meals, or the addition of medical This group estimated approximately 2 million admissions food supplements and/or vitamin and mineral supplements. that involved the diagnosis of malnutrition.5 In the United Recent data collected in 56 countries for the nutrition survey, Kingdom, costs associated with malnutrition are as high as nutritionDays 2006–2014, identified factors associated with $13 billion, which is twice the cost of health care associated placing a patient at risk for malnutrition that were associated with obesity.6 Estimations for malnutrition in children admit- with inadequate oral intake during hospitalizations. World- ted to acute care hospitals range from 6% to 14% in G ­ ermany, wide, factors that placed a patient at risk were older women France, the United Kingdom, and the United States.7 with low body mass index (BMI) who were confined to bed Chapter 5 Enteral and Parenteral Nutrition Support   93 and who had reduced dietary intake the previous week. 13 and the patient’s individual needs, each intervention begins Any time that individuals cannot meet their nutritional needs with the foundational principles presented here. through an oral diet, they should be evaluated for enteral Ethical considerations impact decisions related to SNS, nutrition (EN) (or tube feeding) and/or parenteral nutrition as discussed further in Box 5.2. Patients and their families (PN) administration. Building on the nutrition intervention should be involved in making these decisions. Furthermore, principles discussed in Chapter 4, this chapter focuses on food options for nutrition support therapy should be consistent and nutrient delivery for the primary purpose of preventing or with the level of medical care that the patient is receiving.15 treating malnutrition when nutrient needs cannot be met with an oral diet. The use of nutrition support (in particular, EN 5.2 ENTERAL NUTRITION support) is now recognized as an integral component of the medical care for patients that can blunt the stress response, Enteral nutrition (EN; from the Greek enteron, meaning reduce infections and other medical complications.12 “intestine”) refers to delivery of nutrients distal to (or beyond) Nutrition support via enteral and parenteral nutrition the oral cavity of the GI tract via a tube, catheter, or stoma. is a life-sustaining alternative for patients who are unable to The terms “enteral feeding” and “tube feeding” are used inter- maintain their nutritional status using oral diets or supple- changeably in the clinical setting. Medical and nutritional ments. PN support became an important nutrition inter- research has increased understanding of the need for GI tract vention in the 1970s, as methods were developed to provide stimulation and the overall health benefits of continuing to adequate feedings by vein. Since then, research and economic provide nutrition via the GI tract, especially in the critically necessity have yielded significant technical advancements. ill. The 2016 ASPEN/SCCM Critical Care guidelines recom- Nutrition support has developed rapidly, and practice is chal- mend that: “…nutrition support therapy in the form of early lenging as clinicians strive to keep up with changes in the EN be initiated within 24–48 hours in the critically ill patient field. See Box 5.1 for a brief history of nutrition support. who is unable to maintain volitional intake” (p. 165) and is at A comprehensive nutrition assessment is the first step to nutritional risk.12 determine not only the extent of inadequate nutrition but also the underlying cause of poor oral intake (if present). Com- Indications mon nutrition diagnoses that may necessitate alternate routes EN is indicated for adult patients who have a functioning GI for nutrition interventions include the following: inadequate tract and who present with inadequate oral intake for 7–14 energy intake, inadequate oral intake, inadequate EN infu- days, or in whom inadequate oral intake is expected to con- sion, inadequate PN infusion, inadequate bioactive substance tinue over a 7- to 14-day period.16 The recommended crite- intake, increased nutrient needs, malnutrition, inadequate ria for use of EN in pediatrics include the following: unable protein-energy intake, swallowing difficulty, altered gastro- to obtain >80% of caloric needs by mouth or requiring an intestinal (GI) function, impaired nutrient utilization, unin- extended time period to eat (>4 hours/day) and/or malnu- tended weight loss, suboptimal growth rate, and self-feeding trition or poor growth demonstrated by a decrease of two or difficulty.14 Nutrition support is a significant and extremely more weight or height growth channels or persistent triceps important component of nutrition interventions within the skinfold (TSF) 80% of goal calories should be made in receiving enteral feedings may develop hyperosmolar, non-­ order to achieve the clinical benefit of EN over the first week ketotic dehydration over a short 2- to 4-day period. This con- of hospitalization” (p. 169).12 Overfeeding may lead to a con- dition may be prevented by providing sufficient fluid (about dition called refeeding syndrome. This is discussed in more 1 mL/kcal) with the feeding. Patients receiving less fluid detail below. Overfeeding, on the other hand, may result in Chapter 5 Enteral and Parenteral Nutrition Support   107 Table 5.4 Electrolyte Requirements ill patients. Typically, insulin is initiated when blood glucose is greater than 180mg/dL, and it is recommended to have an Dietary Reference established protocol for insulin management as well as pre- Intake for Oral/ Recommendations for vention of hypoglycemia.43,44 Enteral Feedings Parenteral Intake Refeeding Syndrome Refeeding syndrome is a term Potassium used to describe several common metabolic alterations that. 14 years 4700 mg 1–2 mEq/kg may occur during nutritional repletion of patients who are Sodium malnourished or in a state of starvation.45,46 This syndrome 14–50 years 1500 mg 1–2 mEq/kg has been observed in the surviving victims of famine since the beginning of medical history. With the advent of PN, refeed- 51–70 years 1300 mg ing syndrome gained attention because of its often dramatic. 70 years 1200 mg and sometimes fatal presentation. With starvation lasting Chloride more than a few days, liver gluconeogenesis slows, free fatty 14–50 years 2300 mg To maintain acid–base acids are used to produce energy in the form of ketones, and 51–70 years 2000 mg balance basal metabolic rate declines. The reintroduction of carbohy-. 70 years 1800 mg drate, whether in oral, enteral, or parenteral form, results in a shift from ketones to glucose as the primary energy source. Acetate — To maintain acid–base balance Glucose metabolism requires large quantities of phosphorus. Magnesium, potassium, and thiamin requirements may also Calcium increase to meet anabolic needs. The result is a drop in serum 14–18 years 1300 mg 10–15 mEq levels of phosphorus, which, if severe, may result in hemoly- 19–50 years 1000 mg sis, impaired cardiac function, impaired respiratory function,. 51 years 1200 mg and even death. Hypomagnesemia (low serum magnesium) Magnesium may result in tremor, muscle twitching, cardiac arrhythmias, and even paralysis (see Chapter 7). Hypokalemia (low serum Males 14–18 years 410 mg 8–20 mEq potassium) is also associated with cardiac abnormalities. Thi- 19–30 years 400 mg amin deficiency has been documented infrequently, but may. 31 years 420 mg result in Wernicke’s encephalopathy (see Chapter 16). Patients Females 14–18 years 360 mg 8–20 mEq at risk for refeeding syndrome include those who present with 19–30 years 310 mg malnutrition, those who have a history of long-term inade-. 31 years 320 mg quate oral intake, and those who have had minimal intake for several days as a result of NPO status or poor appetite. It is Phosphorus critical to monitor serum levels of phosphorus, magnesium, 14–18 years 1250 mg 20–40 mmol and potassium and to provide supplementation as needed.. 18 years 700 mg Clinicians begin feedings slowly and avoid overfeeding as Note: These are standard intake ranges for generally healthy people with strategies to prevent refeeding syndrome. See Chapter 7 for essentially normal organ function who do not have abnormal needs or additional information. losses. 5.3 PARENTERAL NUTRITION hyperglycemia, hypertriglyceridemia, and hepatic steatosis The word parenteral means “alongside” or “outside” the (fatty liver), but in reality this is most often associated with GI tract and is now used to describe the administration of poorly monitored, home PN. drugs or nutrients by vein (intravenously [IV]). ­Parenteral While many clinicians prefer to feed hospitalized patients ­nutrition (PN) developed in the 1960s to sustain the lives 25–30 kcal per kg, there are others who prefer to consider of individuals with severe GI impairment and includes IV lower amounts (18–20 kcal/kg) for overweight patients. Cur- ­nutrients delivered through a peripheral vein (PPN) or a rent ASPEN guidelines state: “For all classes of obesity where central vein (CPN). PN was previously referred to as central BMI is >30, the goal of the EN regimen should not exceed venous nutrition (CVN) or intravenous hyperalimentation 60%–70% of target energy requirements or 11–14 kcal/kg (IVH), but PN is now used to encompass all IV delivery of actual body weight per day for patients with BMI 30–50 (or nutrients. The term “hyperalimentation” originally described 22–25 kcal/kg ideal body weight per day for patients with the practice of “hyperalimenting” or overfeeding patients. BMI>50” (p. 198).12 Although deliberately overfeeding or “hyperalimenting” Hyperglycemia During periods of physiological stress, patients is no longer common clinical practice, the term per- such as that caused by severe illness or severe infection sists in many institutions. The distinguishing feature of PN ­(sepsis), hyperglycemia can appear even in patients with no is administration of concentrated macronutrients, vitamins, previous history of diabetes. The hyperglycemia associated minerals, and electrolytes into a large central vein so that the with stress usually resolves as the stress response subsides, volume of blood flow is sufficient to immediately dilute the and nondiabetic patients do not experience long-term compli- concentrated parenteral solutions. cations. Guidelines for the treatment of hyperglycemia during The term peripheral parenteral nutrition (PPN) refers nutrition support vary between critically ill and noncritically to the administration of large-volume, dilute solutions of 108  Part 2 The Nutrition Care Process nutrients into a small vein in the arm or back of the hand. days. Therefore, the osmolarity of the PPN solution should PPN is prescribed for short-term use and is most commonly be confirmed to be 10 days. A ­ ccording to accurate in acute care but this patient 3–5 mg/kg/min. ASPEN guidelines for the Provision and unit does not have access to the Assessment of Nutrition Support Therapy 70 kg × 3 mg/kg/min × 1440 min/day ÷ needed equipment. Many acute care in the Adult Critically Ill Patient,1 “in the 1000 mg/g = 302 g dextrose/day settings and intensive care units use patient at high nutritional risk exclusive the American College of Chest Physi- B. More Critical Thinking: When writing parenteral nutrition (PN) should be initi- cians recommendations for 25–35 kcal the first bag of PN, remember to start ated as soon as possible following ICU × weight (kg). The patient is within the with 10 days. Ht. 5’9”, Wt. 155#, 70 kg × 25 kcal/kg = 1750 kcal additional kcal to be provided by lipid. UBW 165# (6 months ago). 70 kg × 30 kcal/kg = 2100 kcal 302 g dextrose × 3.4 kcal/g = 1028 kcal Nutrition Diagnosis Range: 1750–2100 kcal Predicted inadequate energy intake 105 g protein × 4 kcal/g = 420 kcal C. More Critical Thinking: If indirect related to small bowel resection and diag- calorimetry is not available, use your Total: 1448 kcal from dextrose nosis of Crohn’s disease as evidenced by estimated requirements of EER = and amino acids is our goal. prolonged post-op NPO status. 1750–2100 kcal Use the minimum estimated energy Determine the Parenteral Nutri- STEP 3: CALCULATE A PROTEIN GOAL requirement for the patient. tion Prescription A. Critical Thinking: There is minimal 1750 kcal − 1448 kcal drainage from the surgical wound STEP 1: DETERMINE A “DOSING” WEIGHT = 302 kcal from lipid (100 mL over the last two shifts), A. Critical Thinking: The hospital which would not result in significant B. More Critical Thinking: You know that bed has a built-in scale, so you can protein loss. To support postoperative a 20% lipid emulsion provides 2 kcal/ easily weigh the patient. Physical wound healing, 1.5–1.8 g/kg of pro- mL. Divide the estimated amount of exam reveals no fluid retention. His tein is appropriate. kcal needed to meet the patient’s mini- current BMI of 22.9 is within the B. Calculations for the Nutrient mum energy requirement by the 2 kcal/ healthy weight range so his actual ­Prescription: Multiply the protein mL provided by the lipid emulsion. body weight is recommended for requirement by the patient’s weight. dosing weight in calculating energy 302 kcal ÷ 2 kcal/mL = 151 mL of 20% requirements. 70 × 1.5–1.8 = 105–126 g protein/day lipid emulsion Chapter 5 Enteral and Parenteral Nutrition Support   109  Applying the Nutrition Care Process to Develop a Parenteral Nutrition Prescription (continued) C. More Critical Thinking: Remember, 70 mEq of potassium, 20 mmol of daily to run at 87 mL/hour over 24 hours ASPEN guidelines recommend with- phosphorus, 16 mEq of magnesium, each day. holding soybean-oil-based fat emulsion and 10 mEq of calcium with chloride Total: 1440 kcal from dextrose and amino for the first week of ICU admission. and acetate to balance, with 1 vial of acids and 450 kcals from lipid = 1890 We will assume he is within week 1 ­multiple vitamin infusion and 1 vial of kcal/day or 27 kcal/kg. of admission. Therefore, we would multiple trace element infusion in a vol- wait to start the 151 ml of 20% lipid ume of 2.1 L daily to run at 87 mL/hour A. Critical Thinking: Assess that this emulsion. Therefore, the patient will over 24 hours each day. final solution will meet the patient’s be underfed the first week on PN. On day 2 (the patient is metaboli- nutritional needs: cally stable): increase dextrose to 300 g STEP 7: CONSIDER ELECTROLYTE NEEDS 1890 kcal from PN solution ÷ 70 kg = dextrose/day (rounded from 302 g/day) A. Calculation for Nutrient Prescrip- 27 kcal/kg and 105 g protein/ day. If electrolytes tion: Consult Table 5.4 to identify sug- are stable, continue with 70 mEq of 105 g pro from PN solution ÷ 70 kg = gestions for electrolyte concentration sodium, 70 mEq of potassium, 20 mmol 1.5 g pro/kg in the PN. Based on his dosing weight, of phosphorus, 16 mEq of magnesium, this patient would need about 70 This meets the minimum estimated and 10 mEq of calcium with chloride and mEq of sodium, 70 mEq of potassium, needs for your patient and is within acetate to balance, with 1 vial of multiple 16 mEq of magnesium, 20 mmol of the target amounts for macro- and vitamin infusion and 1 vial of multiple phosphorus, and 10 mEq of calcium micronutrients. trace element infusion in a volume of with chloride and acetate as needed to 2.1 L daily to run at 87 mL/hour over maintain acid–base balance. Reference 24 hours each day. McClave SA, Taylor BE, Martindale RG, et al.; STEP 8: CONSIDER VITAMIN AND MINERAL On day 8 of ICU admission: Reas- A.S.P.E.N. Board of Directors; American Col- NEEDS sess lipid needs and add to PN to meet lege of Critical Care Medicine; Society of Critical Care Medicine. ­Guidelines for the A. Critical Thinking: Consult Tables 5.7 100% estimated nutritional needs. Due Provision and Assessment of Nutrition Sup- and 5.8 to identify appropriate vitamin to compatibility requirements of a 3-in-1 port Therapy in the Adult Critically Ill Patient: and mineral requirements. Remember solution, the pharmacist determines that Society of Critical Care Medicine (SCCM) and to check the package insert for the vita- ­American Society for Parenteral and Enteral a minimum of 225 mL of 20% lipid/day Nutrition (A.S.P.E.N.). J Parenter Enteral Nutr. min and mineral preparations so that is required*, 300 g dextrose/day, 105 g 2016; 40(2): 159–211. you will know how much the patient is protein/ day, and 225 mL of 20% lipid/ getting. All patients will require a multi- day with 70 mEq of sodium, 70 mEq *Compatibility is affected by order of com- pounding, the concentration of macronutrients, vitamin preparation in their PN to avoid of potassium, 20 mmol of phosphorus, pH, and temperature. Generally, 20–60 g lipid/L micronutrient deficiencies. 16 mEq of magnesium, and 10 mEq of (200–600 kcals/L), 40–250 g dextrose/L (136–850 STEP 9: THE FINAL PRESCRIPTION FOR THE calcium with chloride and acetate to kcals/L), and 20–60 g amino acid/L (80–240 balance, with 1 vial of multiple vitamin kcals/L) are standard compatibility requirements for PN SOLUTION ­macronutrients. On day 1: 200 g dextrose/day, 105 g infusion and 1 vial of multiple trace protein/ day with 70 mEq of sodium, element infusion in a volume of 2.1 L Indications necessity for PN must be established in order to ensure that PN is indicated in those clinical situations where the patient the patient’s care is financially feasible. is unable to meet nutritional needs either by an oral diet or through the use of EN. The clinical conditions that may Venous Access Devices require PN include an inability to digest and absorb nutrients, The primary difference between enteral and parenteral such as in massive bowel resection or short bowel syndrome ­feedings is that nutrients are provided via the veins through a (SBS); intractable vomiting, as in hyperemesis gravidarum; vascular access device (VAD) rather than the GI tract in PN. GI tract obstruction; impaired GI motility; and abdominal Feeding directly into the venous system and large-­diameter trauma, injury, or infection. Nutrition diagnoses associated veins allows for use of high-osmolality solutions of >900 with candidates for PN are the same as those for EN. mOsm/L to allow delivery of 100% of the estimated nutrition Decisions related to PN, like those for EN, are based on requirements. The location of the catheter tip determines if the nutrition care process. The patient’s nutrition assessment, a PPN or CPN solution can be infused. Therefore, prior to the length of time the patient will require nutrition support, starting PN confirmation that the catheter tip is located in and the patient’s diagnosis and current medical condition will the vena cava adjacent to the right atrium is critical.47 VADs assist the clinician in making the decisions that are required are available in single-, double-, or triple-lumen models. The to build the PN prescription. Certification of medical lumen of the catheter refers to the interior of the tube through 110  Part 2 The Nutrition Care Process Figure 5.11 Sites for Parenteral Access IV solution Right subclavian vein Internal jugular vein Catheter External jugular vein Left subclavian Hub of vein catheter Right Left cephalic Filter superior vein vena cava Left basilic vein IV tubing Catheter Peripherally Central venous inserted central catheter catheter Source: S. Rolfes, K. Pinna and E. Whitney, Understanding Normal and Clinical Nutrition. 7th ed. Copyright © 2006, p. 677. which the PN solution passes. The number of lumens should Figure 5.12 Types of Venous Access Devices correspond to the number of therapies the patient is requir- Examples of venous access devices that are used for delivery of ing. For example, medications, fluids, and nutrients can all be intravenous nutrients. From left to right: PICC line; tunneled infused through these lumens. Figures 5.11 and 5.12 may be catheter; implanted port that has been accessed; central venous of assistance in visualizing the types and locations of VADs catheter. used for PN. Short-Term VADs The most common VAD is a ­central venous catheter (CVC) or central line inserted ­percutaneously (through the skin) at the bedside while the patient is under local anesthesia. Central catheters are inserted into large veins such as the subclavian, jugular, or femoral veins. Ultimately, these catheters reside in the superior vena cava, or in the infe- rior vena cava, in the case of femoral placement. The use of a CVC placed in the femoral vein should be avoided for admin- istration of PN solutions unless no other vein can be accessed due to the higher rate of infectious complications.47 CVCs are usually changed every few days to help decrease the risk of infection inherent with an opening from the skin into a large, central vein. These catheters are reserved for hospitalized patients and are not considered safe for long-term use. The peripherally inserted central catheter (PICC) is also frequently used. Unlike the CVC, which requires a ­b edside surgical procedure by a physician for insertion, Source: Courtesy of Kristen Roberts, PhD, RDN, LD. the PICC can be inserted by specially trained nurses; this increases the availability of the procedure and decreases costs. PICC lines are inserted into the arm and threaded into Long-Term VAD For long-term use, or for home PN, a cath- the subclavian vein to the vena cava where the tip resides eter is tunneled under the skin during a surgical procedure. adjacent to the right atrium.47 These catheters can be used for Tunneled catheters (such as Hickman®, Broviac®, and Gro- both hospitalized and home PN patients. shong®) most often enter the vein on the upper chest wall and Chapter 5 Enteral and Parenteral Nutrition Support   111 exit the body near the xyphoid process, axilla, or ­abdominal formulas that are adjusted daily to meet the rapidly changing wall. They are considered permanent, and with proper care can needs of critically ill patients. An automated compounder is be left in place for several years. If a tunneled catheter contains used to combine all nutrients needed for a 24-hour infusion more than one lumen, it can accommodate infusions of medi- into a single container. When an automated compounder cations, fluids, or blood products in a­ ddition to PN. Thus, it is is available, the PN prescription may include ingredients in useful for patients who receive IV medications in addition to as small as 1-mL increments. If an automated compounder PN. The number of lumens on the VAD is correlated with risk is not available, formula changes and manufacture are more of developing a catheter line-associated bloodstream infection time consuming for the pharmacist. (CLABSI), and therefore it is critical to minimize the number Automated compounders can be used to manufacture of lumens on the VAD. Therefore, the pharmacist determines nutrient solutions that combine dextrose and amino acids the compatibilty of medications with the PN prescription to (two-in-one formulas) or dextrose, amino acids, and lip- inform the number of lumens required on the VAD. ids (three-in-one formulas). PN can be provided in either Implantable ports are similar to tunneled catheters in a two-in-one or three-in-one system, and each system has that they must be placed in the operating room by a surgeon. both advantages and disadvantages. Typically in the two- They are available with single or double ports and are suit- in-one, lipids are added separately based on the available able for long-term access. Unlike tunneled catheters, they lie container sizes (100 mL, 250 mL, or 500 mL). This system completely under the skin and are more acceptable to patients provides a greater degree of flexibility in the amounts of with body image concerns. Because they are usually placed dextrose and amino acids that can be given since compat- just below the clavicle on the chest wall, they may be diffi- ibility requirements with lipid emulsions are eliminated. cult for the patient to access. Nursing intervention may be Another advantage of the two-in-one system is that formu- required to change needles used to gain access to these ports. las containing only dextrose and amino acids are clear, and any precipitate can be observed. A disadvantage of the two- Solutions in-one system is the need for an additional administration set (IV tubing and other devices required for the delivery of Unlike enteral formulas, which are most often purchased in PN) for the lipids. a form appropriate for patient administration, parenteral for- The three-in-one system requires a single ­administration mulas are mixed or “compounded” in the hospital pharmacy. set, which saves nursing time and reduces costs. On the The method the pharmacy uses to compound PN prepara- other hand, the addition of lipids with the three-in-one tions is critical to development of PN prescriptions. In some ­system results in an opaque solution, which obscures precip- institutions, a standardized approach includes not only stan- itate and increases the risk of particulate being infused into dard ordering and monitoring but also standardized solu- the patient. Addition of lipid into the three-in-one solution tions. Advantages of this approach include improvements ­limits the electrolytes and final concentration of amino acids in efficiency and cost-effectiveness.48 The use of automated in s­ olution, which minimizes the flexibility of dextrose and compounding equipment (see Figure 5.13) and bulk packag- amino acids in the final solution. ing of concentrated macronutrients allows for individualized PN solutions are compounded from as many as 40 ­different items under the supervision of a licensed ­pharmacist. Figure 5.13 A Pharmacy Compounder In order to maintain sterility, compounding is completed in a “clean room” under a laminar flow hood. Because PN Parenteral nutrition is compounded within the pharmacy under aseptic ­conditions. An automated compounder like is ­compounded from amino acid, dextrose, and lipid solu- the one shown here minimizes risks and errors in parenteral tions, solubility is an important consideration ­affecting the nutrition. ­maximum amount of both nutrients and fluid that can be incorporated. Precipitates may form in PN solutions if greater than recommended maximum amounts of electrolytes and minerals are added, especially when PN is subjected to changes in temperature or pH. Likewise, minimum ­volumes are impacted by the concentration of amino acids, dextrose, and lipid that are available for compounding. PN Substrates Protein Protein is included in PN in the form of individual amino acids in amounts consistent with the recommenda- tions of the Food and Agriculture Organization and the World Health Organization. Modified products have been developed and marketed for renal failure, hepatic failure, and stress. Commercial amino acids are available from various manu- facturers in concentrations of 3.5% (35 g/L) to 20% (200 g/L). Lower concentrations (3.5%–5.5%) are used for peripheral administration, while higher concentrations (8.5%, 10%, 11%, Source: Courtesy of Marcia Nelms. 15%, and 20%) are used for CPN administration. Details for 112  Part 2 The Nutrition Care Process Table 5.5 Amino Acid Solutions Used in Parenteral Nutrition Brand Name/Manufacturer Type/Indication Stock Concentrations Aminosyn II™/Hospira Standard 3.5%, 5.2%, 7%, 8.5%, 10% Travasol™/Baxter Standard 10% FreAmine® III/B. Braun Standard 10% ™ Aminosyn II /Hospira Standard/fluid restriction 15% Clinisol™/Baxter Standard/fluid restriction 15% Plenamine/B. Braun Standard/Fluid restrictions 15% Prosol™/Baxter Standard/fluid restrictions 20% ® ProcalAmine /B. Braun Metabolic stress 3% HepatAmine™/B. Braun Hepatic failure 8% ™ Aminosyn HBC /Hospira Metabolic stress 7% FreAmine HBC™/B. Braun Metabolic stress 6.9% ® Trophamine. B. Braun Pediatric 6%, 10% Premasol™, Baxter Pediatric 6%, 10% NephrAmine™ (essential amino acids plus Renal 5.4% histidine)/B. Braun Source: www.bbraunusa.com, hospira.com, www.baxtermedicationdeliveryproducts.com these products are available on Web sites of the major man- fatty acids have been developed but were unavailable in the ufacturers and summarized in Table 5.5. PN is typically United States until 2013, when the FDA granted approval designed to provide individualized protein r­ equirements, for ­Clinolipid™. This ILE is a mixture of olive and soybean which range from 0.8 g/kg for adults to 1.5–2.0 g/kg for oils and is p­ referred by some due to the classification of patients with burns, trauma, or healing wounds.12 being inflammation neutral.50 Most recently, FDA approved Factors that increase protein requirements above the SMOFlipid® for use in the United States, which is the first DRI include diagnoses such as trauma, burns, sepsis, wounds, ILE approved that is characterized as anti-­inflammatory.50 and bone marrow transplant. The lower range of protein (See Figure 5.14.) SMOFlipid ® incorporates soybean oil (0.8 g/kg) may be needed for patients with acute kidney injury (30%), medium chain TGs (30%), olive oil (25%), and fish oil who are not receiving dialysis. It is important to ­remember, (15%). See ­Figure 5.14. Higher omega-3 solutions have been ­however, that without adequate energy from carbohydrate ­e valuated for their anti-inflammatory effects, whereas the and lipid, the subsequent catabolism of lean body mass omega-6 fatty acid profile is considered to be pro-inflam- defeats the effort to control uremia in this manner.49 matory.50 The ILE provides essential fatty acids and vitamin K, as well as a concentrated source of energy—an avenue Carbohydrate The primary function of parenteral to meet energy needs if the patient is unable to tolerate a c­ arbohydrate is to serve as an energy source. In the United higher carbohydrate load. Available formulations contain 10% States, dextrose monohydrate is used as the c­ arbohydrate (1.1 kcal/mL), 20% (2 kcal/mL), or 30% (3 kcal/mL) lipids. source for PN. This particular form of carbohydrate Caloric values per gram depend on the energy provided by ­p rovides 3.4 kcal/g. The minimum carbohydrate intake glycerol, so 10% ­solutions provide 11 kcal/g and the others ­s pecified by the DRI is 130 g/day, and it is known that provide 10 kcal/g. See Table 5.6 for nutrient profiles of rep- ­approximately 100 g of carbohydrate is required daily to allow resentative ILEs. An estimated 2%–4% of energy from linoleic for protein sparing. The amount of 1 mg/kg/min is often used acid is recommended to prevent essential fatty acid deficiency as the reference for the minimal amount of carbohydrate (EFAD). Complications of ILEs, including hyperlipidemia needed to spare protein. The maximum for glucose ­oxidation and impaired immune response, support a more conserva- was originally studied in burn patients and found to be 7 g/ tive ­prescription of lipids. The medication propofol, which is kg/day (5 mg/kg/minute). In practice, lower figures of 3–4 often administered to the critically ill, is lipid based and thus mg/kg/min have been recommended.12 Dextrose is commer- must be considered as a source of energy.12,49 cially available in 5%, 10%, 50%, and 70% concentrations, but other concentrations may also be available. Electrolytes Using the standards established by the DRI as Excessive carbohydrate may contribute to hyperglycemia, the beginning benchmark, electrolyte requirements in PN are hepatic steatosis, and excessive carbon dioxide production. based on body weight, existing electrolyte deficiencies, ongo- The elevated carbon dioxide that occurs with overfeeding ing electrolyte losses, and changes in organ function. Because may jeopardize respiratory status and result in difficulty electrolyte requirements are also inextricably linked with the weaning from mechanical ventilation (see Chapter 21). amount of macronutrients provided in the PN, it is impossi- Lipid The intravenous lipid emulsion (ILE) in most ble to manage PN without a thorough understanding of these ­ arenteral solutions available in the United States since 1972 p complex relationships (see Chapter 8). Recommendations for is an emulsion of soybean oil. Other sources of lipid that standard electrolyte intake are found in Table 5.4. Note, how- contain fewer total omega-6 fatty acids and more omega-3 ever, that in practice electrolytes are individualized according Chapter 5 Enteral and Parenteral Nutrition Support   113  Figure 5.14 SMOF Lipid Trace Minerals Originally, zinc, copper, SMOF lipid emulsion recently received FDA approval for use in the United States as a chromium, and manganese were added lipid source with soybean oil, medium chain triglycerides, olive oil, and fish oil. to PN. Based on reports of deficiencies, newer combination products have been introduced that contain the original trace JIRATIKARN PENGJAIYA/Shutterstock.com / Iurii Kachkovskyi/Shutterstock.com / minerals plus selenium. Trace element combination products are purchased com- Alexander Raths/Shutterstock.com / Valentyn Volkov/Shutterstock.com mercially and contain four or five trace ele- S oybean Oil ments, while iodide, molybdenum, and iron (ω-6) can be purchased as individual injections as needed. In situations where reduced ex- cretion or potential toxicities exist, trace elements are removed from the PN, and M CT individual trace minerals are added accord- 30% ing to need. As mentioned above, levels of 30% PN trace minerals may need to be adjusted to better reflect current understanding of requirements for hospitalized patients.53 Trace element additions for adult PN are 15% listed in Table 5.8. 25% Medications PN may be used to deliver F ish Oil (ω-3) medications. It is possible that albumin, aminophylline, metoclopramide, corti- O live Oil (ω-9) costeroids (i.e., methylprednisolone and hydrocortisone), histamine H2 receptor antagonists (i.e., cimetidine and famotidine, ranitidine), heparin, or regular insulin may Source: http://smoflipid.com be included in PN. Prior to recommending medications be added to PN, the clinician to patient needs and are often considered to be the most should gain a thorough understanding of the practice at his difficult component for new RDNs working with ­nutrition or her institution through observation and consultation with support. a pharmacist. Vitamins and Minerals In 1979, the American Medical Association released Table 5.6 Nutrient Content of Lipid Emulsions Used in Parenteral Nutrition recommendations for vitamin and mineral additives to PN. 51 These vitamin recom- ClinoLipid/ Component1 Intralipid Liposyn2 Omegaven ClinOleic SMOFlipid mendations were used until 2003, when they were revised to include vitamin K.52 Rather Soybean oil, % 100 50 0 20 30 than add individual amounts of vitamins to Safflower oil, % 0 50 0 0 0 PN, most pharmacies purchase commercial Medium-chain triglycerides, % 0 0 0 0 30 multiple-vitamin infusion products that Olive oil, % 0 0 0 80 25 meet the recommendations. Because the vitamins are administered intravenously, Fish Oil, % 0 0 100 0 15 there is no issue with absorption, and the Glycerol, g/100 mL 2.25 2.5 2.5 2.25 2.5 amounts administered may differ from what Egg phospholipid, g/100 mL 1.2 1.2 1.2 1.2 1.2 is recommended for oral intake. ASPEN Phytosterols, mg/100 mL 439 ± 5.7 38.3 3.66 274 ± 2.6 207 recently evaluated the currently available Vitamin E, mg/100 mL 3.8 0 15–30 3.2 16–23 vitamin and mineral parenteral solutions and recommended that the levels of vitamin LA, % 50 66 4.4 18.5 21.4 D, carnitine, choline, and trace elements be ALA, % 9 4.2 1.8 2 2.5 examined and revised. Until formulations EPA, % 0 0 19.2 0 3 are updated, ASPEN suggests individual DHA, % 0 0 12.1 0 2 supplementation may be necessary for some ARA, % 0 0 1–4 0 0.15–0.6 patients. 53 Due to the rapid development 3 of nutrient deficiencies, all PN solutions Vitamin K, mcg/dL 31–67 31–93 Present 0 Present3 should contain a multivitamin product. 1 Anez-Bustillos L, Dao DT, Baker MA, et al. Nutr Clin Prac. 2016; 31: 596–609. Table 5.7 lists daily adult parenteral vitamin 2 Meisel JA, Le HD, Meijer VE, et al. J Ped Surg. 2011; 46: 666–73. requirements. 3 Noted on manufacturer website. 114  Part 2 The Nutrition Care Process Table 5.7 Adult Daily Requirements for Parenteral Vitamins 6. Consider the electrolyte needs for this patient. C ­ orrect electrolyte abnormalities prior to infusing the PN s­ olution. Vitamin Requirement 7. Add a vitamin and mineral preparation. Thiamin 6 mg 8. Consider trace element requirements. Riboflavin 3.6 mg 9. Establish fluid requirements. Niacinamide 40 mg 10. Calculate the final parenteral prescription. Folic acid 600 mcg Pantothenic acid (dexpanthenol) 15 mg Many institutions have specific protocols for initiation, Pyridoxine 6 mg advancement, and transition of feedings. Cyanocobalamin 5 mcg Administration Biotin 60 mcg ASPEN recommends a standardized protocol for delivery of Ascorbic acid 200 mg PN.45 It is recommended that a standardized order form be Retinol 1 mg (3300 USP units) used to ensure basic nutritional needs for patients are met Ergocalciferol 5 mcg (200 USP units) and that errors are minimized. PN can be cycled or deliv- dl-alpha tocopheryl acetate 10 mg (10 USP units) ered continuously over a 24-hour period. The initial PN solution should not exceed 200 grams of dextrose to prevent Phylloquinone 150 mcg PN-­induced hyperglycemia and increased risk of infectious Source: Adapted from Journal of Parenteral and Enteral N ­ utrition by complications.54 A fasting blood glucose level of >200 mg/dL ­Mirtallo, Canada, Johnson, Kumpf, Petersen, Sacks, Seres, Guenter. ­Copyright 2004 by SAGE Publications Inc. Journals. should be corrected to 25% dietary fat [≥50 gm fat daily] found in stool) for PN, should be nonfunctioning. With disuse, a nonfunc- 10% weight loss with an albumin