K e l i P e r i n o , D i e t e t i c I n t e r n J u n e 2 0 1 6

PERITONEAL DIALYSIS MEDICAL NUTRITION THERAPY

OUTLINE

•  Objectives •  Key Terms •  Background •  Dietary Recommendations •  Complications •  Summary

OBJECTIVES

Audience members will be able to explain the primary nutrition intervention goals for

The patient on peritoneal dialysis (PD).

Audience members will be able to to identify key macronutrients (kcal, carbohydrates, protein, & fat)

and micronutrients (vitamins & minerals) to be monitored in the patient on PD.

Audience members will be able to summarize current dietary recommendations for the patient on PD.

KEY TERMS

•  PD – peritoneal dialysis

•  ADP – automated peritoneal dialysis

•  CCPD – continuous cyclic peritoneal dialysis

•  NIPD – nocturnal intermittent peritoneal dialysis

•  TPD – tidal peritoneal dialysis

•  CAPD – continuous ambulatory peritoneal dialysis

•  HD – hemodialysis

•  aBWef – adjusted edema-free body weight

•  EDW – estimated dry weight

•  UF - ultrafiltration

•  HBV – high biological value

BACKGROUND

Kidney Functions – “A WET BED”

•  A: acid base balance

•  W: water balance •  E: electrolyte balance •  T: toxin removal

•  B: blood pressure control •  E: erythropoietin production •  D: vitamin-D metabolism

BACKGROUND - CKD

• 13% of U.S.

• Etiology •  Diabetes •  Hypertension •  Glomerulonephritis •  Genetic & hereditary factors •  Overconsumption of OTC painkillers

BACKGROUND - PD

•  Oldest of all dialysis modalities (1923)

•  Can be managed by patient at home

•  Underutilized in United States

•  6.1% of patients initiate to PD (2009)

•  6.9% of prevalent patients (15% decrease since 1980)

•  From 1997 to 2008, proportion of all dialysis patients treated with PD was unchanged in developing nations, but significantly declined (5.3%) in developed nations

•  Why? ! $$$

BACKGROUND - PD

•  Goal: to maintain optimal nutrition while limiting the build-up of toxic metabolic waste products

•  Mechanism •  Makes use of body’s own semipermeable membrane,

•  Dialysate with dextrose instilled into peritoneum via catheter

•  Diffusion carries waste products through peritoneum into dialysate which is then drained & discarded.

•  New “clean” solution is added & the process repeats

•  This process is called an exchange & takes 20-30 minutes

BACKGROUND - PD

• Amount of solute & fluid removed !

•  Dwell time •  Number of exchanges in a day •  Volume of dialysate used in each exchange •  Dextrose concentration •  A higher dextrose concentration also increases amount of

kcals absorbed ! risk for weight gain, increased triglycerides, & insulin resistance

•  Limit high concentration/hypertonic exchanges = weight gain & decreased ultrafiltration by peritoneal membrane

PD MODALITIES

Two modalities (combinations possible)

1.  Continuous Cyclic (CCPD) •  Shorter dwell time (3-5x/night) •  Requires machine •  Less risk of peritonitis & hernia, better small solute clearance •  Includes NIPD & TD

2.  Continuous Ambulatory (CAPD) •  Longer dwell time (4-5x/day) •  No machine required •  24 hour treatment, less popular

PERITONEAL MEMBRANE CLASSIFICATIONS

The rate at which solutes are removed depends of rate of equilibrium between dialysate & blood.

This varies considerably patient to patient !

•  High Transporters •  Rapid & complete equilibration due to large peritoneal

surface area & membrane permeability •  Rapid loss of osmotic gradient & low net UF •  Higher protein losses •  Short dwells/CCPD ideal

PERITONEAL MEMBRANE CLASSIFICATIONS

•  Low Transporters •  Slower & less complete equilibration

•  Lower membrane permeability

•  Small peritoneal surface area

•  Good UF & maintenance of osmotic gradient

•  Protein losses are lower

•  Long, high volume dwells/CCAP ideal

•  High-Average & Low Average Transporters •  Intermediate clearance, UF, & protein losses

PERITONEAL DIALYSIS

• Advantages •  Longer residual renal function compared to HD!

•  Smaller fluctuations in blood chemistry

•  Less accumulation of waste products & fluid

•  Greater diet liberalization

•  Easy for patient to learn & maintain self-care

•  Increased ability to live normal lifestyle

•  Less expensive (70% of HD cost)

•  Lower risk of death in first 1-2 years as a result of less infection & CHF, & longer residual renal function

PERITONEAL DIALYSIS

• Disadvantages •  Greater protein losses (5-15g/day)

•  Filling of peritoneal cavity (1-3L) = early satiety, fullness, & anorexia = increased risk for malnutrition & wasting

•  GERD & constipation associated with fullness is exacerbated by pressure of fluid on abdomen

•  Risk for peritonitis

•  Ultrafiltration loss

•  Hypokalemia/potassium depletion

•  Excess kcal absorbed from dialysate = possible weight gain, hypertriglyceridemia, & hyperglycemia

DIETARY RECOMMENDATIONS

•  Nutrition Intervention Goals •  Prevent nutrient deficiencies & malnutrition

•  Minimize uremia & associated complications (CVD, anemia, renal osteodystrophy, secondary hyperparathyroidism)

•  Maintain BP & fluid states (edema and electrolytes)

•  Restrict nutrients no more than necessary

•  Continuous adjustments over lifetime based on nutritional status, comorbidities, modality, acute illness, & psychosocial state

NUTRITION PRESCRIPTION PER I TONEAL D IALYS IS

Nutrient Recommendation

Energy* Outpatient: 30-35 kcal/kg >60 y.o. OR ≥35 kcal/kg <60 y.o. Inpatient: Mifflin-St. Jeor Predictive Equation x Activity Factor *include kcal from dialysate in totally daily recommendation

Protein 1.2-1.3 g/kg EDW (≥50% high biological value)

Phosphorus* 800-1000 mg/day or10-15 mg/g protein *PO4 content of diet depends on protein needs; avoiding processed foods will help minimize the P load from food additives

Potassium 2-4 g/day (individualize for maintenance of serum levels WNL)

Calcium ≤2 g/day (elemental)

Sodium 2-3 g/day (maintain fluid balance, minimize hypertonic exchanges)

Fluid* 1-3 L/day (highly individualized) *depending on urine output, UF capability, cardiac status, & blood pressure; maintain fluid balance; minimize hypertonic exchanges

Nutrient Recommendation

Vitamin-C 60-100 mg/day

Vitamin-B6 (pyridoxine) 10 mg/day

Vitamin-B1 (thiamine) 1-5 mg/day

Folic Acid 1-10 mg/day

Vitamin A & E Not routinely needed

Iron 10-15 mg/day; supplement often required

1,25-dihydroxy Vitamin-D or Analogs

Individualize to maintain normal bone turnover, avoid secondary hyperparathyroidism

Vitmain-D2 or Vitmain-D3 Absolute needs are unknown, but nutritional supplements are likely to be beneficial, especially if blood levels are <30 mg/dL

Zinc 15 mg/day as indicated by signs of deficiency

CALCULATING KCALS FROM DIALYSATE

%Dextrose G Dextrose G x 3.4 = kcal available

CAPD kcal absorbed

CCPD kcal absorbed

1.5% 15 51 31-36 kcal/L 20-26 kcal/L

2.5% 25 85 51-60 kcal/L 34-43 kcal/L

4.25% 42.5 145 87-102 kcal/L 58-73 kcal/L

Simple estimate based on dextrose concentration & estimated 60-70% absorption with CAPD & 40-50% with CCPD. This calculation does not consider the membrane characteristics. To estimate total potential calorie load, multiply the number of exchanges times the volume of each exchange in liters times the estimate of calories absorbed. •  CAPD with four 2-L exchanges of 1.5% dextrose: 4 exchanges x 2 L each

exchange x 31 kcal/L = 248 kcal

•  CCPD with three night & one daytime 2-L exchanges of 1.5% dextrose: 4 x 2 x 20 kcal/L = 160 kcal

P E R I T O N E A L D I A LY S I S

CALCULATING KCALS FROM DIALYSATE

FOODS HIGH IN PHOSPHORUS

FOODS LOW IN PHOSPHORUS

SAMPLE MEAL PLAN

COMPLICATIONS

•  Common comorbidities must also be considered •  Cardio Vascular Disease

•  Elevated total cholesterol, LDL & triglycerides common

•  Statin therapy?

•  Overweight/Obesity

•  Weight gain associated with extra kcals from dialysate

•  Limit hypertonic exchanges

•  Diabetes

•  Malnutrition

•  Associated with increased morbidity & mortality

DIABETES CONTINUED

•  PD better than HD •  Steadier biochemical state & fluid balance, decreased

vascular compromise, absence of heparin therapy, simplicity of technique (if patient with poor vision or dexterity in hands & fingers)

•  Close blood glucose monitoring necessary •  Hyperglycemia risk •  Increased insulin use •  Insulin resistance

•  Icodextrin or amino acid solutions as alternatives •  Hypokalemia 2/2 metabolic acidosis

MALNUTRITION CONTINUED

•  Causes •  Increased protein loss •  Decreased intake •  Fullness/early satiety •  Uremia = N/V & taste aberrations •  Fear of eating “wrong” foods, poor tasting diet •  Increased anorexogenic hormones

•  Metabolic acidosis = protein catabolism •  Systemic inflammation 2/2 dialysis, fluid overload, GI

bacterial growth

MALNUTRITION CONTINUED

•  Assessment •  Albumin: not appropriate indicator of nutritional status

•  Losses via dialysate (primary protein lost in PD)

•  Inflammatory status

•  Increased plasma volume from PD fluid = dilution effect

•  Abnormal distribution between intra & extravascular spaces

•  Prealbumin: better, but still not appropriate

•  Weight: not appropriate due to fluid fluctuations (fill weight vs. empty weight)

Subjective Global Assessment (SGA) and/or Protein Catabolic Rate (PCR) – Appropriate!

MALNUTRITION CONTINUED

•  Solutions •  Appetite stimulants (Megace) •  Oral supplements (Boost, Ensure, Nepro,

Beneprotein) •  Meal timing •  Eat during or after draining cycle •  If patient cycles @ night, am meal before last fill •  Small frequent meals, avoid fluid at mealtime

PERITONITIS CONTINUED

•  Inflammation of peritoneal cavity

•  Increases protein loss by 50%

•  Caused by contamination during exchange or exit site infection

•  Malnutrition increases risk for development

•  More common in CAPD (greater number of exchanges = greater risk for contamination)

•  Treat with IV antibiotics

SUMMARY

Nutrition Intervention Goals

•  Restrict nutrients no more than necessary •  Prevent deficiencies & malnutrition

•  Minimize uremia & associated complications •  Weight gain, CVD, anemia, renal osteodystrophy, &

secondary hyperparathyroidism

•  Maintain BP & fluid states •  Edema & electrolyte balance

•  Adjust continuously over life span •  Nutritional status, comorbidities, modality, acute illness &

psychosocial state

SUMMARY

Dietary Recommendations •  Highly individualized, varies considerably patient to patient

•  Same energy needs as HD

•  Don’t forget kcals from dialysate!

•  Fat limited to account for dextrose

•  More protein, potassium, sodium, & fluid

•  Phosphorus still restricted

•  Renal multivitamins (Vitamin-C, B, & ) pic of nut labe

REFERENCES

•  NKF •  UptoDate •  http://www2.kidney.org/professionals/KDOQI/

guidelines_nutrition/doqi_nut.html •  Nutritional Consequences and Benefits of Alternatives to In-

Center Hemodialysis, Renal Nutrition Forum (AND) •  US Renal Data System. USRDS 2011 Annual Data Report: Atlas

of Chronic Kidney Disease and End-Stage Renal Disease in the United States. National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases. Bethesda, MD, 2011.

•  A Clinical Guide to Nutrition Care in Kidney Disease 2nd ed •  Krause •  Jane’s pocket guide with kcals from dialysate table •  Add articles •  INTEXT CITATIONS!!!