Parenteral Nutrition Management for Adult Patients
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NUTRITION ISSUES IN GASTROENTEROLOGY, SERIES #40 Carol Rees Parrish, R.D., M.S., Series Editor The Hitchhiker’s Guide to Parenteral Nutrition Management for Adult Patients Howard Madsen Eric H. Frankel While parenteral nutrition is a life-saving modality for people with intestinal failure, it is not without significant risk. In the hospital setting, under certain clinical circum- stances, patients will also benefit from the use of parenteral nutrition. The purpose of this article is to aid the clinician in the safe provision of parenteral nutrition support, including development of the prescription, appropriate monitoring, and awareness of the issues involved in the preparation and stability of commonly used additives. Frequently asked questions and challenges that arise with the use of parenteral nutri- tion are also addressed. INTRODUCTION cians ordering parenteral nutrition. eeding nutritionally compromised patients has never been as easy, or as hard, as it is today. We INDICATIONS Fare able to provide nutrients parenterally and enterally to patients who once would have been con- The guiding principle of nutrition support is to use the sidered “unfeedable.” Today’s inpatient population is least invasive and most physiologic method of feeding. sicker than patients in the past; the same may be said Infusing chemicals directly into the bloodstream is the for patients needing specialized nutrition support. This least preferred method of providing nutrition support results in challenges to clinicians caring for these (1). Yet, for a select subset of the population, intra- patients. Our goal in writing this article is to provide a venous infusion of central parenteral nutrition (PN) or succinct and easy to follow guide for practicing clini- peripheral parenteral nutrition (PPN) is the only viable means to provide substrates for metabolism. PN carries Howard Madsen, RD, Pharm.D., Nutrition Support with it inherent risks associated with the placement of a Pharmacy Practice Resident and Eric H. Frankel, central venous catheter. Due to the increased risk of MSE, Pharm.D., BCNSP, Nutrition Support Coordina- complications with PN therapy, including thrombosis tor, Covenant Health System, Lubbock, Texas. and infection, a careful assessment of PN appropriate- 46 PRACTICAL GASTROENTEROLOGY • JULY 2006 The Hitchhiker’s Guide to Parenteral Nutrition Management NUTRITION ISSUES IN GASTROENTEROLOGY, SERIES #40 Table 1 Table 2 Indications, Relative Indications and Contraindications Important Factors to Consider when Assessing a Patient for Parenteral Nutrition for Parenteral Nutrition Parenteral nutrition is usually indicated in the • Anthropometric Data – include: following situations – Recent weight changes • Documented inability to absorb adequate nutrients via the – Current height and weight GI tract such as: • Lab values – including: – Massive small-bowel resection/short bowel syndrome – Comprehensive metabolic panel (at least initially) – Serum magnesium level – Radiation enteritis – Serum phosphorus level – Severe diarrhea – Serum triglycerides as indicated (Table 18) – Untreatable steatorrhea/malabsorption (i.e., not pancre- • Medical/Surgical History atic insufficiency, small bowel bacterial overgrowth, or – Anatomy (resections)/ostomies celiac disease) – Pre-existing conditions such as diabetes, renal failure, • Complete bowel obstruction, or intestinal pseudo-obstruction liver disease, etc. • Severe catabolism with or without malnutrition when GI tract • Diet/Medication History – include: is not usable within 5–7 days – Food/drug allergies • Inability to obtain enteral access – Diet intake prior to admission • Inability to provide sufficient nutrients/fluids enterally – Special diets • Pancreatitis accompanied by abdominal pain with jejunal – Herbal/supplement use delivery of nutrients – Home and current medications • Persistent GI hemorrhage • Acute abdomen/ileus • Lengthy GI work-up requiring NPO status for several days in ness should precede placement of a central venous a malnourished patient catheter (1,2). Table 1 lists indications and contraindi- • High output enterocutaneous fistula (>500 mL) and inability cations for PN. to gain enteral access distal to the fistula site • Trauma requiring repeat surgical procedures Parenteral nutrition may be indicated in the following situations PATIENT ASSESSMENT • Enterocutaneous fistula Prior to initiating PN, a nutrition assessment is neces- • Inflammatory bowel disease not responding to medical therapy • Hyperemesis gravidarum when nausea and vomiting persist sary to determine nutrient needs and to anticipate any longer than 5–7 days and enteral nutrition is not possible metabolic changes that may occur due to the patient’s • Partial small bowel obstruction underlying condition, medications or concurrent thera- • Intensive chemotherapy/severe mucositis pies, etc. Table 2 provides a list of factors to consider • Major surgery/stress when enteral nutrition not expected to when assessing a patient’s nutritional status. Deter- resume within 7–10 days • Intractable vomiting when jejunal feeding is not possible mining energy and protein needs in the severely mal- • Chylous ascites or chylothorax when low fat/fat free EN does nourished patient under physical stress, often ventila- not adequately decrease output tor-dependent with little mobility, can be difficult. Critical illness brings further challenges in determin- Contraindications for Parenteral Nutrition • Functioning gastrointestinal tract ing the appropriate calorie level, as matching caloric • Treatment anticipated for less than 5 days in patients without expenditure to caloric provision may be detrimental— severe malnutrition providing lower calorie levels initially has been advo- • Inability to obtain venous access cated (3,4). Calorie requirements often increase in • A prognosis that does not warrant aggressive nutrition support relation to stress, fever, and seizures, while a decrease • When the risks of PN are judged to exceed the potential benefits in needs may be seen in the setting of sedation or Used with permission from the University of Virginia Health System reduced mobility. While indirect calorimetry is consid- Nutrition Support Traineeship Syllabus (Parrish CR, Krenitsky J, ered the “gold standard” to determine caloric expendi- McCray S). Parenteral Module. University of Virginia Health System Nutrition Support Traineeship Syllabus, 2003. ture, formulas and calculations are frequently used. Unfortunately, no studies to date have demonstrated PRACTICAL GASTROENTEROLOGY • JULY 2006 47 The Hitchhiker’s Guide to Parenteral Nutrition Management NUTRITION ISSUES IN GASTROENTEROLOGY, SERIES #40 Table 3 Daily Energy and Substrate Guidelines for Adult PN (5–8) Nutrient Acute Care Critical Care Energy 25–30 total kcals/kg/d 25 total kcals/kg/d • Refeeding 15–25 kcal/kg/d 15–25 kcal/kg/d • Obesity (≥130% IBW) 15–20 kcal/kg/d adjusted weight * 15–20 kcal/kg/d adjusted weight * Protein 0.8–1.0 g/kg/d maintenance 1.5–2.2 g/kg/d 1.2–2.0 g/kg/d catabolism Dextrose <7 g/kg/d <5 g/kg/d Lipid** <2.5 g/kg/d 0.4–0.75 g/kg/d *Adjusted weight based on a 50% correction factor ([usual weight – ideal body weight] × 0.50) **If a patient is to be on PN for greater than 3 weeks, a minimum of 2%–4% of total calories should come from IV fat emulsion (IVFE) including linoleic acid to prevent essential fatty acid deficiency (EFAD) (9) benefit by comparing the use of metabolic cart results mal renal, cardiac, hepatic, and pulmonary function. with various formulas in terms of clinical outcomes. Due to the risk of thrombophlebitis, these solutions are Regardless of which calculation is used to estimate generally limited to an osmolarity of <600–900 nutrient requirements, it is important to note that there is mOsm/L (12,14). See Table 5 and Table 6 for calcula- a lack of evidence correlating a given calorie and pro- tion of mOsm in parenteral solutions. Even at 600–900 tein level to clinical outcomes, and the controversy over mOsm, these solutions are hypertonic, hence any which formula is “best” is ongoing. Guidelines for patient with poor peripheral access should not receive designing PN formulations have been developed by var- PPN. Instead, alternatives should be considered, based ious organizations and experts in the field of specialized on the individual patient’s circumstances. These nutrition support, some of which are listed on Table 3. include the use of Central PN or provision of peripheral protein-sparing IV fluids containing 5% dextrose. The anticipated duration of parenteral support and how VENOUS ACCESS soon the patient may be transitioned to enteral nutrition Line type, nutrition formulation and other medication will factor into this decision. Patients with rapid or fre- needs are inter-related and need to be approached in a quent loss of peripheral access with IV fluids (D5, etc.) unified manner. Table 4 describes the advantages and are poor candidates for PPN. As a rule of thumb, if the disadvantages of intravenous access typically used for patient’s peripheral access has been changed 2–3 times parenteral nutrition support. Nutritional limitations within the first 48 hours following admission on stan- associated with those lines are also provided. Further dard IV fluids, PPN should not be attempted. Combi- details on these topics have been included in the follow- nations of heparin and hydrocortisone added to the PPN ing paragraphs. formulation, with or without the use of a nitroglycerin patch placed proximal, and as close as