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Parenteral Nutrition: Assessment & Management Techniques Kris M. Mogensen, MS, RD, LDN, CNSC Team Leader Dietitian Department of Nutrition Brigham and Women’s Hospital December 8, 2014 Overview • • • • • • • • • • Deciding who needs parenteral nutrition Peripheral vs. central parenteral nutrition Nutrition assessment Protein Carbohydrate Fat Fluid requirements Additives Calculating the PN prescription Monitoring/complications Overview • • • • • • • • • • Deciding who needs parenteral nutrition Peripheral vs. central parenteral nutrition Nutrition assessment Protein Carbohydrate Fat Fluid requirements Additives Calculating the PN prescription Monitoring/complications Who needs PN? • PN carries a fair amount of risk – Inserting a central line, infections, metabolic complications… • If the gut works, and can be used safely, use it! Typical Indications for PN • • • • • • • Diffuse peritonitis Intestinal ischemia Intestinal obstruction Paralytic ileus Severe diarrhea (> 1 liter/day) Severe malabsorption Intestinal failure Other Indications • Failed enteral trial or inability to obtain enteral access – Severe pancreatitis – Prolonged severe mucositis – Multi-organ system failure A.S.P.E.N. Board of Directors and The Clinical Guidelines Task Force. Guidelines for the use of parenteral and enteral nutrition in adult and pediatric patients. JPEN 2002 BWH Algorithm for Determining Route of Nutrition Support Consider nutritional support if any of the following conditions are present: • Patient has been without nutrition for 5-7 days • Expected duration of illness > 10 days • Patient is malnourished (weight loss > 10% of usual weight) Initiate nutritional support only if tissue perfusion is adequate and electrolytes and acid-base balance are near normal Is GI output > 600 ml/24 hr, massive GI hemorrhage, prolonged ileus or other contraindication to enteral feeding? NO YES Administer Parenteral Nutrition Initiate Enteral Feedings Enteral Feeding Tolerated Enteral feeding not tolerated Initiate CPN Initiate PPN Reassess PN need Overview • • • • • • • • • • Deciding who needs parenteral nutrition Peripheral vs. central parenteral nutrition Nutrition assessment Protein Carbohydrate Fat Fluid requirements Additives Calculating the PN prescription Monitoring/complications Peripheral vs. Central PN • Decision process – Duration of therapy – Type of venous access – Status of peripheral veins – Energy and protein needs – Volume required Peripheral PN Safety Point Boullata JI et al. A.S.P.E.N. clinical guidelines: parenteral nutrition ordering, order review, compounding, labeling, and dispensing. JPEN 2014 Peripheral PN • • • • Safety concern: thrombophlebitis High osmolarity increases risk Need good peripheral access Amino acid and dextrose concentrations are low to keep osmolarity ≤ 900 mOsm/L • This typically means a solution that is < 10% dextrose and < 5% amino acids, with most of the energy delivery from fat • Need large volume (up to 2-3 L/day) Peripheral PN • Practical safety concern: – If large volume is required to provide a substantial amount of energy and protein, are there patients who should not be peripheral PN candidates? Central PN • Hyperosmolar solution, > 900 mOsm/L • Can meet energy and protein needs in a concentrated volume • Requires central venous access • Tip of the catheter must be in the superior vena cava Mirtallo J et al. Safe practices for parenteral nutrition. JPEN. 2004 Preferred catheter tip location for PN From Nelms, Nutrition Therapy and Pathophysiology, 2nd ed, 2011. Overview • • • • • • • • • • Deciding who needs parenteral nutrition Peripheral vs. central parenteral nutrition Nutrition assessment Protein Carbohydrate Fat Fluid requirements Additives Calculating the PN prescription Monitoring/complications Nutrition Assessment • Your PN prescription is driven by your nutritional assessment – Is the patient malnourished? – Is there risk of the refeeding syndrome? – What are the patient’s energy, protein, and fluid requirements? – Does the patient need specialized nutrients or additives to the PN? Energy Requirements • In the good old days, PN was referred to “hyperalimentation” – This is a misnomer; the current practice is to avoid overfeeding – Provide what your patient needs to prevent complications such as hyperglycemia & fatty liver • Bottom line: – Estimate energy requirements carefully or measure when you can – Avoid overfeeding! Mirtallo J et al. Safe practices for parenteral nutrition. JPEN. 2004 Overview • • • • • • • • • • Deciding who needs parenteral nutrition Peripheral vs. central parenteral nutrition Nutrition assessment Protein Carbohydrate Fat Fluid requirements Additives Calculating the PN prescription Monitoring/complications Protein • Protein in PN is provided as crystalline amino acids • Parenteral amino acids provide 4 kcal/g • Various concentrations are available – 8.5% up to 20% as a base solution • Total amino acid delivery depends on your assessment of protein requirements Protein (continued) • Safety point: – For a total nutrient admixture (3-in-1): • At least ≥ 4% amino acid concentration for appropriate stability – However, lots of considerations for stability, so it’s important to work with your pharmacist on this! Boullata JI et al. A.S.P.E.N. clinical guidelines: parenteral nutrition ordering, order review, compounding, labeling, and dispensing. JPEN 2014 Overview • • • • • • • • • • Deciding who needs parenteral nutrition Peripheral vs. central parenteral nutrition Nutrition assessment Protein Carbohydrate Fat Fluid requirements Additives Calculating the PN prescription Monitoring/complications Carbohydrate • Parenteral CHO is dextrose • Provides 3.4 kcal/g • Total dextrose delivery depends on energy requirements – 50-60% kcals from dextrose for CPN – ~ 30% kcals from dextrose for PPN • Base solutions range from 50-70% dextrose • Final dextrose concentration depends on – Peripheral vs. central infusion – Volume requirements • Concentrated PN = higher dextrose concentration • Safety point: for a 3-in-1 PN, dextrose concentration should be ≥ 10% Boullata JI et al. A.S.P.E.N. clinical guidelines: parenteral nutrition ordering, order review, compounding, labeling, and dispensing. JPEN 2014 Carbohydrate (continued) • CHO safety point: avoid overfeeding! • Maximum oxidative rate: – 5 mg/kg/minute • Example calculation: – 70 kg pt x 5 mg x 1440 minutes/day = 504,000 mg dextrose = 504 grams Mirtallo J et al. Safe practices for parenteral nutrition. JPEN. 2004 Carbohydrate (continued) • Consequences of short-term overfeeding: – – – – Hyperglycemia CO2 retention Increased respiratory drive Respiratory distress • Long-term overfeeding of dextrose can lead to fatty liver – Overfeeding total calories from all macronutrients can lead to a fatty liver! Overview • • • • • • • • • • • Deciding who needs parenteral nutrition IV access Peripheral vs. central parenteral nutrition Nutrition assessment Protein Carbohydrate Fat Fluid requirements Additives Calculating the PN prescription Monitoring/complications Fat • IV fat emulsion (IVFE) is an important source of calories and essential fatty acids • IVFE is comprised of: – Soybean oil or a blend of soybean & safflower oil – Also includes phospholipids and glycerol Fat (continued) • Safety points: – For a 3-in-1 PN, lipid concentration should be ≥ 2% – Provide enough fat to meet essential fatty acid requirements • 4% - 6% of total calories – Avoid too much fat • Generally restrict to ~ 1 g/kg • Some give 20% - 30% of total calories as fat • Maximum 2.5 g/kg Boullata JI et al. A.S.P.E.N. clinical guidelines: parenteral nutrition ordering, order review, compounding, labeling, and dispensing. JPEN 2014 Mirtallo J et al. Safe practices for parenteral nutrition. JPEN. 2004 Comparison of IV Fat Emulsions Concentration 10% 20% 30% kcal/mL Fat g/L (9.3 kcal/g) Phospholipid g/L (6 kcal/g) 1.1 100 12 2 200 12 2.9 300 12 Glycerol g/L (4.2 kcal/g) 22.5 22.5 17 Example: 250 mL 20% IVFE = 500 kcals, 50 g fat, 3 g phospholipid, 5.625 g glycerol Parenteral fat does NOT provide 10 kcal/gram!!!! Fat (continued) • Monitor triglycerides to assess lipid clearance – Pancreatitis may occur with TG > 500 mg/dL – Hold IVFE if TG > 400 mg/dL • Other possible complications – Hypersensitivity reaction • Fever, chills, chest or back pain, dyspnea, cyanosis – True allergic reaction • Hives, anaphylaxis Overview • • • • • • • • • • Deciding who needs parenteral nutrition Peripheral vs. central parenteral nutrition Nutrition assessment Protein Carbohydrate Fat Fluid requirements Additives Calculating the PN prescription Monitoring/complications Fluid • There are many ways to estimate maintenance fluid needs: – 1500 mL for the 1st 20 kg, then 20 mL/kg • For > 65 y.o., decrease to 15 mL/kg – 1500 mL/m2 – 30-40 mL/kg for an average sized adult – 30-40 mL/kg age 18-64 – 30 mL/kg age 55-65 – 25 mL/kg > age 65 – RDA = 1 mL/kcal Fluid Safety point: too much or too little fluid may harm your patient! • Risk of dehydration: – Severe diarrhea – Fistula – Gastrostomy tube for obstructed patients – Vomiting • Risk of volume overload – – – – CHF ESRD ESLD/ascites Anasarca Monitoring Fluid Status • In the hospital: – Input/output – Weight – Blood pressure – Orthostatics • Check BP supine, seated, standing – Physical exam – Labs: sodium, BUN:creatinine ratio Monitoring Fluid Status • At home: – – – – – Frequency of urination, color of urine Output from ostomy, fistula, or tubes Presence/absence of thirst, perspiration Fevers? Ask about orthostatics • “Are you dizzy when you stand up?” – Weight trend – Virtual physical exam • “Are your ankles puffy?” – Labs: sodium, BUN:creatinine ratio Pitting edema From: http://medicine.ucsd.edu/Clinicalimg/extremities-massive-edema.html, accessed 4/30/07 Assessing skin turgor From: http://www.nlm.nih.gov/medlineplus/ency/imagepages/17223.htm, accessed 4/30/07 Overview • • • • • • • • • • Deciding who needs parenteral nutrition Peripheral vs. central parenteral nutrition Nutrition assessment Protein Carbohydrate Fat Fluid requirements Additives Calculating the PN prescription Monitoring/complications PN Additives • Electrolytes • 10 mL MVI-13 daily – Can add additional vitamins separately if necessary • Trace elements – Can add additional trace elements separately if necessary • Carnitine • Medications Electrolytes in PN Mirtallo J et al. Safe practices for parenteral nutrition. JPEN. 2004 Electrolytes in PN Additive Usual Amt Modified Amount Condition Na (mEq/L) 60-80 30-40 120-140 Renal or liver failure Na deficit (diarrhea) K (mEq/L) 40-60 0-20 Renal failure, hyperkalemia Excess losses or increased needs 60-120 Chloride* (mEq/L) 60-80 30-40 120-140 Metabolic alkalosis Cl deficit (gastric) Acetate* (mEq/L) 20-40 100-120 Metabolic acidosis, chronic diarrhea *Adjust to maintain acid/base balance Electrolytes in PN Additive Phosphate (mMol/L) Usual Modified Condition Amount Amount 10-20 0-5 Renal failure 30-40 Malnutrition Magnesium 8-16 (mEq/L) 0-8 24-32 Renal failure Excess losses (diarrhea) Calcium (mEq/L) 0 12.5-15 Hypercalcemia Low iCa; osteoporosis 5-10 What forms of electrolytes do we use? • Sodium chloride • Sodium acetate • Sodium phosphate – Each 3 mMol NaPhos=3 mMol phos & 4 mEq Na • Potassium chloride • Potassium acetate • Potassium phosphate – Each 3 mMol KPhos=3 mMol phos & 4.4 mEq K • Magnesium sulfate • Calcium gluconate Ordering Electrolytes in PN Ayers P et al. A.S.P.E.N. Parenteral Nutrition Safety Consensus Recommendations. JPEN 2014 Order Snapshot Ayers P et al. A.S.P.E.N. Parenteral Nutrition Safety Consensus Recommendations. JPEN 2014 Electrolytes in PN • Not all institutions follow this process yet – Order “per bag/day” vs. “per liter” – Order single electrolytes vs. salts • There will be a learning curve depending on the current institution’s practice – Ordering based on salts vs. individual electrolytes – Improved knowledge of compatibilities • Working with the nutrition support pharmacist is essential to do this safely! Parenteral Vitamins Mirtallo J et al. Safe practices for parenteral nutrition. JPEN. 2004 Parenteral Trace Elements Mirtallo J et al. Safe practices for parenteral nutrition. JPEN. 2004 Vitamin/Mineral Monitoring • For long-term PN patients, check every 6 months • Copper and manganese are of particular concern for toxicity • Zinc deficiency can be an issue for patients with excessive losses • Watch iron levels - may need separate iron repletion • Yearly DEXA in long-term patients Other Additives • Carnitine – Essential for fat metabolism – Long-term PN patients are at risk for deficiency • Medications – Insulin – H2 blockers – Heparin – Steroids (hydrocortisone) Rarely added Importance of Glucose Control Blood Sugar > 200 mg/dL Impaired leukocyte phagocytic function Increased risk for infection Target Blood Glucose • A.S.P.E.N. Clinical Guidelines A.S.P.E.N. Clinical Guidelines: Nutrition Support of Adult Patients with Hyperglycemia McMahon MM et al. JPEN 2013 How to Achieve Glucose Control? • In the ICU setting – Often continuous insulin infusion • Non-ICU – Generally start with a regular insulin sliding scale, checking BGs every 6 hours – Add half to two-thirds of prior day’s insulin to the PN solution – Patients with known DM often need insulin added to PN on day one – Work with your nutrition support pharmacist or endocrinologist to determine best way to achieve glucose control Glucose Control for Home • Balance good glucose control with avoiding hypoglycemia! • It’s important to think about what is safe for the patient and work with the nutrition support pharmacist and physician to optimize glucose control Overview • • • • • • • • • • Deciding who needs parenteral nutrition Peripheral vs. central parenteral nutrition Nutrition assessment Protein Carbohydrate Fat Fluid requirements Additives Calculating the PN prescription Monitoring/complications Putting It All Together… You need to figure out how to fit all of these components into your patient’s PN solution! Sterile Water Additives IVFE Amino Acids Dextrose Writing the PN Prescription • Now, the fun part! • This is basically a lot of calculations, so it’s best done through a case study: – 55 year old woman with a bowel obstruction from ovarian cancer – Plan is for conservative management – She has a G-tube for decompression & plan is for nutrition support via PN Writing the PN Prescription • Anthropometric: – Height 66” Weight 52 kg – IBW 59 kg 88% IBW • Needs: – 1600 kcals (~ 31 kcal/kg) – 80g protein (~ 1.5 g/kg) – 1800 mL Fluid (35 mL/kg) UBW 58 kg ~ 90% UBW Do the Math! 1. Your protein is a known, so calculate calories from protein: • 80 grams/day x 4 kcal/gram = 320 kcals Do the Math! 2. Determine amount of fat you will provide the patient: • • • • • • • Let’s give 25% of calories from fat: 1600 kcals x 0.25 = 400 kcals If we use 20% IVFE, this will give us 40 grams of fat 400 kcals ÷ 2 kcal/mL = 200 mL 200 mL x 0.2 = 40 grams Cross check for safety—grams of fat/kg? 40g ÷ 52 kg = 0.77 g/kg so we are ok! Do the Math! 3. Add up kcals from protein and fat: • • 320 + 400 = 720 kcals from protein & fat So make up the rest of the kcals from dextrose: • • • • 1600 kcals – 720 = 880 kcals for dextrose 880 kcals ÷ 3.4 kcal/g = ~ 260 grams dextrose Does this exceed her maximum? Let’s find out by calculating the glucose infusion rate: • • 260 g x 1000 = 260,000 mg 260,000 mg/52 kg/1440 min = ~ 3.5 mg/kg/min Do the Math! • Sometimes I calculate the maximum glucose infusion rate, so I know what my maximum is: – 5 mg x 52 kg x 1440 minutes/day = 374,400 mg dextrose = 374.4 grams – Ok to round to 374 grams! The calculations are done…now what? • We need to come up with an order • Let’s look at that snapshot of an order again Order Snapshot Our PN: AA 80g Dextrose 260g IVFE 40g Volume 1.8 L Safety check: 80g AA ÷ 1.8L = ~ 44g/L = 4.4 g/dL 260g dex ÷ 1.8L = ~ 144 g/L = 14.4 g/dL 40g fat ÷ 1.8L = ~ 22g/L = 2.2 g/dL Ayers P et al. A.S.P.E.N. Parenteral Nutrition Safety Consensus Recommendations. JPEN 2014 But…what about the additives? • Depending on where you work, the RDs may or may not make the final recommendations for all of the electrolytes. • This often depends on experience with making electrolyte adjustments in TPN. • Do not hesitate to consult the pharmacy and/or the medical/surgical team for assistance! • But here’s what I’d do in this case: First, I’d review the labs: Lab Value Normal Range Na 138 136-142 mMol/L K 3.6 3.5-5 mMol/L Cl 95 98-108 mMol/L CO2 32 23-32 mMol/L BUN 18 9-25 mg/dL Creatinine 0.6 0.7-1.3 mg/dL BUN:Cr 30 < 20 Random Glucose 98 54-118 mg/dL Calcium 9.0 8.8-10.5 mg/dL Magnesium 1.8 1.8-2.5 mEq/L Phosphorus 2.7 2.5-4.5 mg/dL Triglycerides 77 35-150 mg/dL Then I’d come up with a “starter” order Amino Acids Dextrose IVFE 40g 100 g 20g Sodium phosphate 20 mMol Sodium chloride 60 mEq Sodium acetate 0 mEq Potassium phosphate 0 mEq Potassium chloride 40 mEq Potassium acetate 0 mEq Magnesium sulfate 10 mEq Calcium gluconate 10 mEq Total volume •Start with the lower end of the normal range for additives •Add more chloride than acetate to offset losses •Give high end of magnesium and phos 1 liter Daily additives: 10 mL MVI-13, 1 mL MTE-5 How would I initiate & advance the PN? • I typically take 3 days to get to the goal, depending on the patient and the amount of dextrose in the solution – Day 1: start with 1 liter of the solution – Day 2: increase to 1.4 liters and adjust macronutrients to get 2/3 of the way to goal – Day 3: increase to the goal – Start with no more than 100-150 g dextrose in the first day, but could start with more dextrose depending on prior IVF What if the patient is getting ready to go home? How do I “cycle” the PN? • First, what’s cycling? – Infusing only part of the day (typically over night) to allow the patient time off of the pump – Important for quality of life! • Depending on blood glucoses, I might do this over 2-3 nights: • Cycle day 1: infuse over 18 hours • Cycle day 2: infuse over 16 hours • Cycle day 3: infuse over 12 hours – Check a finger-stick blood glucose at the midpoint of the cycle to assess for hyperglycemia – The PN requires a “ramp-up” and a “ramp-down” to avoid help avoid hyper/hypoglycemia EVERYBODY PRACTICE! Practice Case • Calculate a goal PN prescription for this patient: – 85 kg patient – Needs 2500 kcals and 128g protein – You will give 30 mL/kg, which is about 2500 mL/day Overview • • • • • • • • • • Deciding who needs parenteral nutrition Peripheral vs. central parenteral nutrition Nutrition assessment Protein Carbohydrate Fat Fluid requirements Additives Calculating the PN prescription Monitoring/complications Hospital Monitoring • Prior to initiating PN, electrolyte imbalances should be corrected • Check daily: – Na, K, Cl, CO2, BUN, Cr, BG, Ca, Mg, Phos • Check prior to therapy, then weekly – CBC, LFTs (but in reality, CBC is often daily) • Monitor TG twice/wk to assess lipid clearance • Daily weights, strict I/O to monitor fluid balance • Readiness to transition to enteral or oral diet Mirtallo J et al. Safe practices for parenteral nutrition. JPEN. 2004 Home Monitoring • Check weekly: – Na, K, Cl, CO2, BUN, Cr, BG, Ca, Mg, Phos, LFTs, triglycerides, CBC with differential – As the patient stabilizes, transition to every other week labs, then monthly labs • Daily weights • Weekly nursing visit • Weekly phone call from RD to assess hydration, overall patient status – Can decrease RD follow-up calls if pt is very stable • Vitamin/mineral panel every 6 months • DEXA scan yearly Complications Associated with PN • Metabolic – Electrolyte imbalance • Hyper/hypokalemia • Hyper/hypomagnesemia • Hyper/hypophosphatemia – Hyper/hypoglycemia – Metabolic bone disease • Gastrointestinal – Cholestasis – Fatty liver – GI atrophy Complications Associated with PN (continued) • Infectious – Central line associated bloodstream infection – Central line insertion site infections • Mechanical – – – – – – – – Arterial laceration Pneumothorax Hydrothorax Air embolism Nerve injury Phlebitis (especially if using a PICC) Venous thrombosis Venous sclerosis Conclusions • PN is a complex therapy • Reserve for patients with intestinal dysfunction • Be aware of the complications associated with PN and be proactive in preventing what you can • Work closely with your nutrition support pharmacist to develop a safe PN ordering process for your institution and individual patients • The team approach is an important part of safe management of PN Thank you!