How To Treat A Diabetic Coma With Tpn

Transcription

1 GUIDELINES FOR TOTAL PARENTERAL NUTRITION (TPN) IN ADULT BONE MARROW TRANSPLANT PATIENTS TPN Indications TPN is indicated for any patient who is not expected to eat sufficiently for 3-5 days in severe malnutrition, 5-7 days in mild or moderate malnutrition, and 7-10 days in well-nourished patients. The most important causes leading to malnutrition in BMT patients are: 1. Nausea, vomiting, and diarrhea, catabolism and malabsorption associated with cytoreduction. 2. Taste alterations, electrolyte derangements, protein loosing associated with the course of GVHD. 3. Cachexia due to the primary disease (recent weight loss & poor oral intake). 4. Poor nutritional intake due to mucositis associated with cytoreduction. How much calories with TPN All patients should receive Kcal/kg/day based on the degree of malnutrition and tolerance to different macronutrients. Hypercatabolic patients i.e. sepsis, may not tolerate more than Kcal/kg/day due to pre-existing glucose intolerance, uremia, and/or hypertriglyceridemia. The goal of TPN therapy is to preserve the patient s muscle mass. Weight gain with TPN is almost impossible due to production of catabolic hormones associated with BMT stress. Clinical and biochemical monitoring are necessary to reduce the chance of mechanical, septic, metabolic, and hepatic complications of TPN. Dextrose Dose Day 1: Start with 2mg/kg/min (2.5-3g/kg/day). Day 2: Increase to 3mg/kg/min (4-4.5g/kg/day). Day 3 and thereafter: Increase to 4 mg/kg/min (5.5-6g/kg/day). Do not advance dextrose doses until Potassium and Phosphates levels are corrected. (Due to intracellular shifts) Minimum dextrose dose per day (even in glucose intolerant patients) is g/day to avoid catabolism. Always take in consideration the dextrose load from the side IV maintenance and IVPBs when calculating the total dextrose load.

2 The preferred IV maintenance with TPN is D5W 1/2NS, D5W 1/4NS, or D5W NS. Presence of dextrose with IV fluid will prevent the risk of hypoglycemia if TPN is stopped abruptly or accidentally (line leaking, accidental removal, bag leaking, going for procedure, etc.) Do not allow glucose levels more than 11 mmol/l. Glucose intolerant patients should be prescribed IV insulin sliding scale: Example: Mix by adding 100 units of regular insulin to 100ml Normal Saline: Blood Glucose: (Do fingerstix q 6 hours) 10.1 to 12 mmol/l: 1 unit (1ml)/hour 12.1 to 14 mmol/l: 2 units (2ml)/hour 14.1 to 16 mmol/l: 3 units (3ml)/hour 16.1 to 18 mmol/l: 4 units (4ml)/hour 18.1 to 20 mmol/l: 6 units (6ml)/hour More than 20 mmol/l: Call MD Insulin may be added to TPN 1-2 days after starting sliding scale. Start by adding 2/3 of insulin dose from sliding scale. Reduction of steroid doses, and/or resolved sepsis are indications for random reduction of insulin doses with TPN. Try to limit insulin requirement to 50 units per day. More Potassium, Phosphates, and Magnesium are required during insulin therapy due to intracellular shift of these ions. Elevated transaminases levels days after starting TPN is an indication to reduce dextrose doses in TPN (dextrose-induced liponeogenesis leading to fatty liver). Protein (Amino Acids) Day 1: 0.5g/kg/d Day 2: 1 g/kg/d Day 3 and thereafter: g/kg/d Advance protein as tolerated while monitoring BUN level. Reduce the dose to 0.5g/kg/day with elevated BUN (more than 30 mmol/l) unless on dialysis therapy. Protein dose is guided by monitoring BUN (daily), Nitrogen Balance (once weekly), Prealbumin, and Transferrin (q sat). Elevated LFTs and bilirubin may necessitate limiting protein dose to 1-1.2g/kg/day. 2

3 IV Lipid (Fat) 1. Day 1: 0.5g/kg/day 2. Day 2 and thereafter: 1g/kg/day 3. Limit the rate of infusion to 0.15g/kg/hour. 4. Limiting the dose to 1g/kg/day in BMT patients especially with febrile neutropenia may be necessary due to possible inhibition of chemotaxis and phagocytosis by high lipid doses. 5. If TG less than 2 mmol/l: 1g/kg/d 6. If TG level is mmol/l : g/kg/d. Do TG level q Sat & Wed. 7. If TG level is 4-5 mmol/l: g/kg/d. Do TG levels q Sat, Mon, Wed. 8. If TG level is more than 5 mmol/l: DC IV lipid and do TG levels q Sat, Mon, Wed. 9. The due time for IV lipid is around 0500 (after blood draw) and infused over hours. Minimum of 4 hours is required for clearance before drawing blood to avoid falsely elevated triglyceride levels. Electrolytes Electrolytes are added based on levels. Common Drugs causing electrolytes imbalances: Furosemide: Hypokalemia, hypomagnesemia, hyponatremia, metabolic alkalosis. Cyclosporine: Hypomagnesemia, Hyperkalemia, Hyperglycemia, Hypertriglyceridemia. Amphotericin B: Hypokalemia, hypomagnesemia, renal tubular acidosis. Steroids: Hypokalemia, hyperglycemia. Aminoglycosides: Hyperkalemia (2 nd to ARF). Insulin: Hypokalemia, hypophosphatemia. Spironolactone & Triamterene: Hyperkalemia, metabolic acidosis. Trace Elements: (Zinc, Selenium, Copper, Chromium) Normal dose: 0.05ml/kg/day Additional dose of zinc for all BMT patients: 3-5mg/day, and in diarrhea: 17mg/L of stool loss. Reduce the dose to half in patients with chronic renal failure as chromium, zinc, and selenium are excreted renally. Reduce the dose to half in patients with cholestasis as copper and manganese are excreted in bile. 3

4 Fluid Considerations The physician designates total fluid intake (TFI) in ml/hour. TPN and lipids are ordered at a rate much lower than TFI to allow for antibiotics, blood products, and chemotherapy to be given without exceeding maximum desired TFI. Catching up to the ordered TFI occurs with D5W 1/4NS, D5W 1/2NS, or D5W NS (as per sodium need). Plain NS, 1/2NS, 1/4NS can be ordered temporarily if patient is developing uncontrolled glucose intolerance. For peripheral parenteral nutrition, more fluid is needed to allow more calories provision as dextrose concentration will be limited to 7.5% and Amino Acids to 2.5%. Total Osmolality of the peripheral TPN should not exceed 900 mosm/l. TPN, Lipid, and IV Drugs Compatibility No drugs must be co-infused with the same lumen of TPN or lipid without referring to TPN and Medication Compatibility Guide that is posted in the nursing units. IV Fat can be temporarily turned off when co-infusing a drug that is compatible with TPN but not with lipid. Tapering and Discontinuation When the primary reason for starting TPN is resolving (i.e. mucositis, diarrhea, vomiting etc), taper TPN by reducing the rate into half for one hour then DC TPN. Discontinuation of TPN will stimulate the appetite further. TPN and Liver Dysfunction 1. Transient elevation of transaminases few days after starting TPN reflects nutritional repletion and unlikely hepatotoxicity. 2. Elevated Transminases two weeks after starting TPN is usually the first sign of hepatotoxicity. Reducing dextrose load in TPN may be indicated to reduce the chance of liponeogenesis and hepatic steatosis. If LFTs remain elevated, reduce IV lipid, then amino acids. 3. Elevated conjugated bilirubin during the TPN course is most likely due to NPO status, primary disease, sepsis, drug-induced, then TPN components. Encouraging Oral/enteral intake is recommended to stimulate bile flow and to promote gut trophic effect. Reducing amino acids and IV lipid in TPN may be recommended. 4. Discourage NPO at all times as it may lead to bacterial translocation. Minimal amount of oral/enteral intake is recommended even if not absorbed. The earlier you feed, the better the later tolerance. 5. Consider empirical Metronidazole course ( po/iv q8h x 2 weeks) if infectious workup is negative, and anaerobic intestinal bacterial overgrowth is suspected. 6. TPN may be held temporarily if suspected VOD. 4

5 Team Responsibilities Physician: Orders: Start TPN, taper TPN, DC TPN, total fluid intake in ml/hour, designates desired IV maintenance with TPN. (Note that new start TPN orders are accepted daily excluding weekends. Any TPN order written after 1600 will be processed next day). Consults with TPN Pharmacist on medical circumstances requiring special consideration in TPN nutrients. Enters ordered laboratory orders (by TPN pharmacist) into Integrated Clinical Information System (ICIS). Orders all TPN related medications: Spironolactone, Triamterene, Ranitidine, Insulin, electrolytes boluses, if required before next TPN bag arrives. TPN Pharmacist: Nutritional assessment of the patient, in conjunction with the dietitian. TPN formula design to meet nutritional needs. Daily writing of TPN orders to include lab evaluation, fluid needs, caloric and protein needs. Daily calculation of calories and protein (to include all sources of glucose from IVPB, IV fluids, etc.) Daily order of necessary laboratory orders. Monitor drug-nutrient and lab-nutrient interactions. 24-hour on call (Pager # 9261). Nursing staff: Draws blood (turn off for one full minute before drawing all labs and avoid contamination of the drawn blood with TPN). Determines adequacy of oral intake. TPN monitoring: Daily weights, intake and output, TPN infusion rates and times. Ensure safe drug administration in regard to compatibility of drugs with TPN and lipids. 5