How I assess nutritional requirements and prescribe TPN
•Download as PPTX, PDF•
19 likes•8,235 views
How I assess nutritional requirements and prescribe TPN
Recommended
More Related Content
What's hot
What's hot (20)
Similar to How I assess nutritional requirements and prescribe TPN
Similar to How I assess nutritional requirements and prescribe TPN (20)
More from SMACC Conference
More from SMACC Conference (20)
Recently uploaded
Recently uploaded (20)
How I assess nutritional requirements and prescribe TPN
- 1. Prescribing TPN in the ICU & The Important Questions YASMINE ALI ABDELHAMID MBBS FRACP FCICM Doctoral Candidate, Discipline of Acute Care Medicine, University of Adelaide, Australia Staff Specialist, Intensive Care Unit, Royal Adelaide Hospital, Australia
- 2. Disclosures • Royal Adelaide Hospital Research Committee A.R. Clarkson Scholarship
- 3. Adult Vitamin for Parenteral Nutrition Guidelines
- 5. Why feed? • Hypercatabolism • Muscle wasting & weakness • mortality with calorie & protein deficit Chapple et al., Crit Care Resus, 2017; Puthucheary et al., JAMA, 2013; Heyland et al., Crit Care Med, 2011
- 7. Studies comparing EN vs PN Limited evidence • Overfeeding in PN & underfeeding in EN groups • Protein & energy not standardised • Underpowered • Preceded modern glycaemic control • Early generation lipids
- 8. • 2400 ICU patients • Randomised to early EN or PN • No difference in 30-day mortality Harvey et al., NEJM, 2014
- 9. No difference in mortality Elke et al., Crit Care, 2016 More infectious complications with PN
- 10. EN vs PN? EN is…. • Associated with less infections • Preserves integrity of GI epithelium • Simpler • Cheaper Casaer et al. NEJM, 2014
- 11. Who should receive TPN? • EN contraindicated or unable to tolerate • Malnourished • Surgical patients with impaired GI function – high output fistula – bowel not in continuity – bowel obstruction – short bowel – prolonged ileus
- 12. How much energy? Normocaloric feeding Match caloric intake to 80-100% of energy expenditure Singer et al., Clinical Nutrition, 2009 McClave et al., JPEN, 2016
- 13. How much energy? • Indirect calorimetry often impractical • Not always available • Needs to be repeated frequently • Not superior to formula-based feeding Singer et al. Intensive Care Med, 2011
- 14. • 130 ICU patients: IC vs formula-based feeding • No difference in hospital mortality • ICU LOS & ventilation increased with IC Singer et al., Intensive Care Med, 2011
- 15. How much energy? • Predictive equations (e.g. Harris-Benedict, Schofield) inaccurate developed in healthy individuals Schofield et al., Clinical Nutrition, 1985
- 16. How much energy? • Fixed equations Inaccurate and not evidence-based Many favour simplistic weight-based equation Cerra et al., Chest, 1997
- 17. How much energy? • Fixed equations Inaccurate and not evidence-based Many favour simplistic weight-based equation ACCP recommendation: 25 kcal/kg/day Cerra et al., Chest, 1997
- 18. How much protein? • Limit to dietary protein used for synthesis • Recommendations: 1.2-2 g/kg/day • 2g/kg/day if catabolic e.g. burns • Hypocaloric high protein feeding in obesity controversial Cerra et al., Chest, 1997
- 19. Davies et al., Crit Care Med, in press
- 20. What is in a ~2L bag of TPN?
- 21. Lipid 100g • Olive & soybean oils • Glycerol & egg phosphatides • Provides essential fatty acids (linoleic & linolenic acids) • 9 kcal/g
- 22. TPN lipids • Immune and inflammatory effects • No clear answer on best lipid formulation Calder et al., Am J Clin Nutr, 2006 Singer et al., Clinical Nutrition, 2009
- 23. Protein 100g • As L-amino acids • Preparations vary in amino acids • 5 kcal/g • With or without electrolytes • 70mmol Na • Up to 60mmol K • 5mmol Mg • 30mmol PO4
- 24. Carbohydrate 250g • As glucose • 4.1 kcal/g Energy • Total 2350 kcal • Non-nitrogen 1950 kcal • 1.1-1.2 kcal/mL
- 25. How to prescribe? Optimal balance between carbohydrate & lipid unknown • 30-40% of non-protein energy as lipid • Alternative approaches • Care with glucose > 4mg/kg/min
- 26. How to prescribe? • Daily requirements infused over 24h • Start slowly & titrate up if at risk of refeeding • Administer as an all-in-one bag Singer et al., Clinical Nutrition, 2009
- 27. How to prescribe? EXAMPLE: 70kg ICU patient with severe ileus
- 28. How to prescribe? EXAMPLE: 70kg ICU patient with severe ileus 1. Determine total caloric requirement 70kg x 25kcal = 1750 kcal/day Or use alternative equation
- 29. How to prescribe? EXAMPLE: 70kg ICU patient with severe ileus 1. Determine total caloric requirement 70kg x 25kcal = 1750 kcal/day Or use alternative equation 2. Infuse TPN at… 1750 kcal/day ÷ 1.1 kcal/mL = 1590 mL/day = 66 mL/h
- 30. How to prescribe? EXAMPLE: 70kg ICU patient with severe ileus 1. Determine total caloric requirement 70kg x 25kcal = 1750 kcal/day Or use alternative equation 2. Infuse TPN at… 1750 kcal/day ÷ 1.1 kcal/mL = 1590 mL/day = 66 mL/h 3. Protein requirement 70kg x 1.2g = 84 g/day 1590mL/2000mL x 100g protein = 79.5 g/day received
- 31. How to prescribe? EXAMPLE: 70kg ICU patient with severe ileus 4. CHO 1590 mL/2000mL x 250g glucose = 199 g/day received x 4.1 kcal/g = 816 kcal/day received
- 32. How to prescribe? EXAMPLE: 70kg ICU patient with severe ileus 4. CHO 1590 mL/2000mL x 250g glucose = 199 g/day received x 4.1 kcal/g = 816 kcal/day received 5. Fat emulsion 1590 mL/2000mL x 100g fat = 80 g/day received x 9 kcal/g = 720 kcal/day; CHO:fat 55:45
- 33. How to prescribe? EXAMPLE: 70kg ICU patient with severe ileus 4. CHO 1590 mL/2000mL x 250g glucose = 199 g/day received x 4.1 kcal/g = 816 kcal/day received 5. Fat emulsion 1590 mL/2000mL x 100g fat = 80 g/day received x 9 kcal/g = 720 kcal/day; CHO:fat 55:45 6. Estimate fluid and electrolyte requirements Additional water to be added if needed: 30-40 mL/kg/day Additional electrolytes as needed
- 34. Don’t Forget… • Vitamins and trace elements Thiamine Folate Vitamin K • Daily IV multivitamin & trace elements • Thiamine in at risk • Lab monitoring not routine except vitamin D • Ensure light protection Adult Vitamin for Parenteral Nutrition Guidelines
- 35. Practicalities • Needs central venous line • Dedicated lumen • Daily bag & infusion set changes • Sterile conditions if adding to TPN (not ward) vitamins, trace elements, insulin • Care when ceasing
- 36. Monitoring Complications • Infection • Electrolytes & refeeding syndrome • Glucose • Hyperchloraemic metabolic acidosis • Liver dysfunction • Lipids • Nutritional intake • Fluid balance • Trace element & vitamin deficiency
- 37. When do we start PN? Doig et al., JAMA, 2013 • 1372 patients: early PN vs standard care • No difference in 60-day mortality or LOS
- 38. Is there a role for supplemental PN? • 4640 patients: early supplementation of EN with PN vs waiting 1 week • Shorter ICU & hospital LOS in late PN group • Less organ support in late PN group • Less infections in late PN group Casaer et al., NEJM, 2011
- 39. Is there a role for immunonutrition? • Glutamine • Omega 3 fatty acids • Arginine • Selenium • Other
- 40. Gunst et al., Curr Opin Crit Care, 2017
- 41. Gunst et al., Curr Opin Crit Care, 2017
- 42. Gunst et al., Curr Opin Crit Care, 2017
- 43. Summary • Nutrition is important - feed enterally early • Enteral route is preferred when possible • Benefit from TPN mainly when EN is delayed • Safe to wait for TPN if not malnourished • Aim for 25 kcal/kg/day • Immunonutrition not routine
- 45. How to prescribe? EXAMPLE: 70kg ICU patient with severe ileus
- 46. How to prescribe? EXAMPLE: 70kg ICU patient with severe ileus 1. Determine total caloric requirement 70kg x 25kcal = 1750kcal/day Or use alternative equation
- 47. How to prescribe? EXAMPLE: 70kg ICU patient with severe ileus 1. Determine total caloric requirement 70kg x 25kcal = 1750kcal/day Or use alternative equation 2. Determine protein requirement 70kg x 1.25g = 87.5 g/day 350kcal
- 48. How to prescribe? EXAMPLE: 70kg ICU patient with severe ileus 1. Determine total caloric requirement 70kg x 25kcal = 1750kcal/day Or use alternative equation 2. Determine protein requirement 70kg x 1.25g = 87.5 g/day 350kcal 3. Divide remaining caloric requirement between CHO:fat (60:40 or 70:30) If 60:40 1400kcal x 0.6 = 840kcal CHO 1400kcal x 0.4 = 560kcal lipid
- 49. How to prescribe? EXAMPLE: 70kg ICU patient with severe ileus 4. Calculate amount of CHO needed If using 50% dextrose solution (2kcal/mL) 840kcal CHO = 420mL
- 50. How to prescribe? EXAMPLE: 70kg ICU patient with severe ileus 4. Calculate amount of CHO needed If using 50% dextrose solution (2kcal/mL) 840kcal CHO = 420mL 5. Calculate amount of fat emulsion If using 20% clinoleic (2kcal/ml) 560kcal lipid = 280mL
- 51. How to prescribe? EXAMPLE: 70kg ICU patient with severe ileus 4. Calculate amount of CHO needed If using 50% dextrose solution (2kcal/mL) 840kcal CHO = 420mL 5. Calculate amount of fat emulsion If using 20% clinoleic (2kcal/ml) 560kcal lipid = 280mL 6. Estimate fluid and electrolyte requirements Additional water to be added to meet fluid requirement if needed: 30-40 mL/kg/day Additional electrolytes as needed
- 53. • The order of admixing of the above components should be approached by minimising a sudden change in the negative charge of the emulsion. Firstly, mix the glucose infusion with the amino acid infusion. ClinOleic 20% emulsion can then be added into this admixture. Finally the electrolyte complements then trace elements can be added. • As the lipid emulsion is negatively charged, do not add electrolytes or trace elements directly into ClinOleic 20% emulsion as they destabilise the emulsion. The recommended sequence for adding electrolytes is monovalent, divalent, and trivalent ions. Phosphates salts must always be added prior to calcium salts as discussed below.
- 56. Is underfeeding safe? • Trophic feeding
- 57. Other Questions • Peripheral PN – fat based, avoids high concentration/osmolarity glucose, used in paeds • Paeds • Long-term TPN – Essential and non-essential amino acids – Vitamins – Closer monitoring
Editor's Notes
- A wide variety of studies, conflicting evidence, and clinical practice guidelines. Keep it simple/practical but also focus a bit on the key studies. Not just a recipe book.
- No grants of relevance to this presentation.
- ESPEN guidelines older 2009. ASPEN 2016. Europeans are more pro-TPN. ASPEN guidelines don’t just focus on TPN.
- Observational studies have associated caloric and/or protein deficit with increased mortality. Association does not prove causation. Work done by Lee-anne Chapple at our centre – US of quadriceps in ICU patients with TBI. These two images are 4 weeks apart. Significant muscle loss. 53yo man TBI, 2.58cm vs 1.28cm.
- Hard to talk about PN if we don’t know where it fits in relation to EN.
- Clinical practice guidelines generally recommend early EN over PN. But…
- CALORIES trial: 2400 ICU patients who could be fed through either route randomised to early (~24h) EN or PN. Achieved similar caloric intake (~20kcal/kg/day). Primary outcome (30-day mortality) no different. No difference in secondary endpoints but more vomiting in EN group. Study used older lipids – n6 polyunsaturated fatty acids.
- A large number of meta-analyses with conflicting results. Recent meta-analysis comparing early EN vs PN found no mortality difference, but reduced infectious complications with EN. ?due to overfeeding in PN groups and poor blood glucose control. Also significant publication bias.
- Less infections may be due to poor glycaemic control and overfeeding in older studies. While there may be no difference between EN and PN when an isocaloric and isonitrogenous dose is given, EN is simpler, cheaper and preserves GI mucosa.
- Will discuss timing later. Malnourished group – difficult to know what to do. Many excluded from lots of studies e.g. EDEN. Might actually do worse if overfed – refeeding. No one knows. Should generally avoid fasting in this group.
- Feeding guidelines recommend…. Normocaloric feeding. Either estimated or measured energy expenditure.
- Indirect calorimetry measures resting energy expenditure by calculating the metabolic rate through measurements of O2 consumption (VO2) and CO2 production (VCO2). No clear data to relate measured REE to total energy expenditure. I don’t use it in my practice.
- Formula-based feeding targeted 25 kcal/kg/day. EN+/-PN. IC performed every 48 hours. IC group received 600kcal/day more. Trend to improved mortality.
- Predictive equations: predict BMR on basis of weight, sex and age. Correction factors to convert predicted BMR into estimated energy expenditure by adjusting for diagnosis, fever, activity. Correction factors can be excessive and contribute to overfeeding.
- Simplistic weight-based equation 20-30kcal/kg/day. American College of Chest Physicians.
- Simplistic weight-based equation 20-30kcal/kg/day. American College of Chest Physicians, proposed in 1997. Adjust with stress factors sometimes. Recent interest in hypocaloric feeding in acute illness. Recent studies looking at EN. EDEN study (JAMA 2012): ARDS patients - full (1300kcal/d) vs trophic (400kcal/d) EN in first 6 day. No difference in ventilator free days, mortality or infections. Less GI intolerance with trophic feeds. 2 recent meta-analyses (Marik, Intensive Care Med, 2016 & Al-Dorzi, Crit Care, 2016): intentional and unintentional enteral hypcaloric or trophic feeding not associated with increased mortality. Caution in meta-analysis which included RCTs in which underfeeding was not intentional. No evidence overall that a certain caloric intake improves mortality.
- ASPEN guidelines recommend 1.2-2g/kg/day protein. Limited basis for this recommendation. Lots of protein zealots. Can’t find benefit with calories, so look to protein. This type of feeding in obesity is suggested but not proven.
- From 14 RCTs involving >3000 critically ill patients No demonstrable effect of protein on mortality. First meta-analysis of protein delivery in critical care nutrition Statistical power (3238 patients and 844 mortality events) Inclusion of only randomized trials Inclusion of trials of nutrition by any route Relatively low amount of protein delivered - Still under guideline recommendations Various study designs Only one specifically designed to assess the impact of protein delivery Statistical (and clinical) heterogeneity Confounding by calorie delivery Risk of bias
- Commercially available, sterile. Who uses all in one bags?
- In a 2.1L bag of TPN:….. Can just be soybean oil, or soybean and coconut oil. Clinoleic in my hospital is a combination 80% olive oil, 20% soya oil.. Emulsified with… Many hospital pharmacies purchase premixed ready-to-use PN products that are either dual-chamber (amino acids and dextrose, with or without electrolytes) or triple-chamber (amino acids, dextrose and lipid). Shortly prior to infusion, the internal membranes separating the chambers are broken, their contents intermixed and vitamins, trace minerals and additional electrolytes added. These products are convenient and potentially cost-effective, but their fixed nutrient composition is a drawback. They are commonly provided in volumes calculated to match the patient’s calorie requirement, with resulting under-provision of amino acids. A variety of dual-chamber amino acid/dextrose products are available, so—at least when the protein requirement does not exceed ~1.5 g/kg per day—it is possible to meet a patient’s protein requirement and avoid calorie overfeeding by selecting an appropriate fixed-composition product. The downside of this approach is the inconvenience of stocking the pharmacy with many different premixed products. In some situations—especially critical illness, in which 2.5 g/kg protein substrate per day may be required—a computer-controlled sterile compounder is necessary. This instrument combines stock amino acid solutions (15 to 20 g/100 mL) and dextrose (70 g/100 mL) to create mixtures of amino acids and dextrose that precisely meet both the protein and calorie requirements of individual patients, and in a much smaller volume. A later section of this article illustrates the advantages of this approach.
- Fatty acids Effects on cell membrane structure and function Alter gene expression Modify inflammatory mediator profile Old n6-polyunsaturated fatty acids from soybean lipids could affect white cell activity. Olive oil based/unsaturated fats may be better – not proven, signal in vitro sudies.
- In a 2.1L bag of TPN:….. Protein from egg or potato. Synthamin Amino acid solutions are sterile, nonpyrogenic, hypertonic, clear and colourless to slightly yellow solutions of essential and non-essential L-amino acids. Electrolytes: Na, K, Mg
- In a 2.1L bag of TPN:…..
- Lipid can be infused once or twice a week, with glucose relied upon for almost all energy. But can have hyperglycaemia, lipogenesis, fatty liver, and excess CO2. While lipid might modify/suppress immune function, so does hyperglycaemia. Some commercial preparations are closer to 50:50 CHO:lipid.
- ESPEN guidelines: All-in-one bags recommended. Safe: associated with an decreased risk of administration errors, as well as of septic and metabolic complications. Less expensive and more time efficient. ASPEN guidelines: all-in-one commercial bags no advantage; can’t tailor to individual patients.
- Check why this often doesn’t include protein. total energy: 25 kcal/kg/day protein: 1.5g/kg/day carbohydrate: 4g/kg/day lipids: 1g/kg/day H2O: 30mL/kg/day + other losses electrolytes organic vitamins inorganic trace elements
- Average 70kg man gets 1.2g/kg/day protein – lower end of recommended protein.
- Usually need 2-4g/kg/day glucose.
- Daily fat intake 1-2g/kg/day
- Especially vulnerable to depletion. Limited evidence for any specific dose of vitamin or trace element. AUSPEN guidelines on recommended daily requirements. Commercially available vitamin & trace element solutions. Weekly vitamin K. Check vitamin D in long-term TPN. Burns patients: higher zinc and selenium. Prefer to give as a separate infusion over several hours to allow cellular uptake before renal excretion. Can interact with PN. Free radical formation in TPN: Lipid peroxidation of the polyunsaturated fatty acids occurs if they are exposed to light, accelerated by phototherapy.
- Dedicated CVC lumen for TPN only. Long-term TPN may need tunneled line. Avoid 3-way taps. Infusion set changes should be carried out daily under sterile conditions. Reduce rate slowly, don’t five insulin for a few hours. Or give IV dextrose.
- Dedicated CVC lumen for TPN only. Avoid 3-way taps. Infusion set changes should be carried out daily under sterile conditions. Long-term TPN may need tunnelled line. Phosphate, potassium, magnesium & supplement. Refeeding syndrome due increased insulin and cellular uptake of these ions. Get depletion of ATP and failure of cellular energy metabolism. Hyper and hypo (if stop suddenly) glycaemia possible. Monitor 4 hourly at start and end. Wean TPN over 12 hours minimum or use 10% dextrose. Hyper – consider more fat. Hyperchloraemia if use amino acid solutions high in chloride. Replace with acetate. Liver dysfunction – hepatic steatosis, intrahepatic cholestasis and biliary sludging from gallbladder inactivity. Consider cyclic 12-16h of TPN instead of 24h, ensure not overfeeding, try different fat emulsion, give some oral intake if can. Especially thiamine, folate and vitamin K.
- Multi-centre RCT. Patients not able to receive EN within 2 days of ICU admission. Early PN within 24h of ICU admission. Reduced ventilator days (3° outcome) – less important. Criticisms: PN use in standard care arm not standardised. More than 1/3 of patients in standard care arm also received PN. Many patients excluded. Stopped early.
- EPaNIC study: Multicentre RCT. Early supplementation of insufficient EN with PN vs late. Criticisms: use IV glucose as maintenance, tight glycaemic control protocol, 60% were cardiac surgery, high calorie/low protein feed regimen, unblinded, did not identify patients unable to receive EN. ?suppression of autophagy by more aggressive feeding: no maintenance of cellular integrity, removal of cell damage. In summary, early initiation of supplemental PN is not beneficial and may be harmful. Can wait until Day 8.
- immune dysregulation and oxidative stress that can predispose patients to infection. Parenteral supplementation with specific nutrients such as arginine, glutamine and omega-3 fatty acids may modulate inflammation and upregulate immune responses. Small studies have suggested certain nutrients with immune-modulating properties may improve outcomes for ICU patients. Not confirmed in larger trials and some have suggested harm.
- Good review article
- Several substances studied simultaneously sometimes.
- May be ok to accept low macronutrient intake during the acute phase of critical illness. E.g. EDEN study EN is cheaper, simpler. Not clearly associated with more complications than isocaloric, isonitrogenous dose of PN. Current evidence does not support use of early PN. Withholding TPN until 1 week after ICU admission is clinically superior to early institution of PN. Optimal timing of when PN can be initiated safely and effectively is unclear. European Society of Parenteral and Enteral Nutrition Guidelines on Parenteral Nutrition in Intensive Care: supplemental PN should be considered when EN is insufficient for more than 2 days to prevent energy and protein deficiency in critically ill patients
- total energy: 25 kcal/kg/day protein: 1.5g/kg/day carbohydrate: 4g/kg/day lipids: 1g/kg/day H2O: 30mL/kg/day + other losses electrolytes organic vitamins inorganic trace elements
- Grimm et al., Critical Care, 2013 Muscle magnetic resonance imaging (1.5 Tesla) of a sepsis patient and a healthy control. Left: sepsis patient at day 14. Right: healthy control. Short TI inversion recovery (STIR) is a magnetic resonance imaging (MRI) sequence to suppress the signal from fat, so that especially edema can be seen in the muscle. The images demonstrate that at day 14 after onset of severe sepsis the structural changes in the muscle (atrophic and fibrous changes) dominate over edematous changes. Ultrasonic sections of the same subjects through the rectus femoris muscle (large arrows) are shown at the bottom. The corresponding areas in MRI are marked as rectangles. The difference in echogenicity of the muscle can clearly be seen. Moreover, the bone signal in the patient begins to blur (small arrows).