PD prescription

Peritoneal Dialysis Prescription&

Adequatcy

Piti Niyomsirivanich,MD.

• Peritoneal dialysis prescription– Acute• Introduction• Peritoneal Catheter• Use of automate cycler• Prescribing acute peritoneal dialysis• Complications

• Chronic• Choice of PD treatment modality

– Modalities of PD therapy CAPD , APD ,hybrid– CAPD or PD ?

• Choice of prescription– Clearance targets– Measurement of clearance– Determinants of clearance– prescription

• Nutritional issues in PD

Acute peritoneal dialysis presciption


Introduction

• Acute Peritoneal Dialysis – Nonvascular alternative for dialysis– Acutely less efficient than conventional

hemodialysis

Adventage / DisadventageAdventage Disadventage

• Technically simpler than that of hemodialysis

• Doesn’t require highly trained personnel or expensive, complex equipment

• Can be instituted quickly• Avoids the potential problems

related to vascularhemorrhage , air embolism , thrombosis , infection

• Lower likelyhood of hypotensive episodes

•Less efficient than hemodialysis (flash pulmonary edema , drug overdose , acidosis ,hyperkalemia , catabolic patient)•Protein loss malnourished•Hyperglycemia

•Serious morbidity (30%) and mortality (5%) attributed Acute PD and HD are similar

Indications

• Acute renal failure• Benefit in volume overload with

cardiovascular compromise• Hypothermia• Hemorrhagic pancreatitis• Most beneficial in Rx of hemodynamically

unstable

Contraindications

• Recent surgery requiring abdominal drains • Known fecal or fungal peritonitis• Pleuroperitoneal fistula

• Relative contraindication– Severe hypercatabolic states– Abdominal wall cellulitis– Adynamic ileus– Presence of abdominal adhesions or fibrosis – New aortic prosthesis


Peritoneal catheter

• Pts. With – multiorgan system failure – Prolong period of renal failure

• initial insertion of a Tenckhoff catheter (preferred > uncuffed temporary catheter) is recommended

Can be anticipated


Use of automated cyclers

• Traditionally been done using manual exchanged

• Automated cyclers are being used instead– Saving nursing time (30-60 minutes exchange time)


Prescribing acute peritoneal dialysis

• A: Session length– In the setting of acute renal failure (catabolic ,

oliguric ), continuous removal of fluids and solutes is required

– Need for hourly exchange on a continuous basis for days or weeks

– Order for One day

Standard order for 1 day

Exchange volume

• Average-sized adult can usually tolerate 2L exchanges– Those with abdominal wall or inguinal hernias, the

exchange volume should be reduced

• Some may prefer start with smaller volumes(1-1.5 L) for the first few exchanges

• The larger volume is , the greater the clearance and UF rates

Exchange time

– Inflow 15 – dwell 30 - drain 15– 1 hr.

• Inflow time– Gravity– 10 min.– Prolonged• Kinking• Inflow resistance

• Inflow pain due to acidic , hypertonic solution

Exchange time

• Dwell period• Standard dwell period– Usual dwell time is 30 min– 2L per exchage 48 L per day– [Urea] in drained dialysate will be 50-60% of plasma

• More stable patients– If Not extremely hypercatabolic state

• longer dwell time 1.5-5 hrs

– At 5 hrs [UREA] dialysate = [UREA]plasma

Exchange time

• Outflow time– Gravity– 20-30 min– Depend on• Total volume• Resistance to outflow• Height• 1st exchange• Outflow obstruction• Outflow pain

CEPD (Continouous equilibration peritoneal dialysis)

• Alternative approach• Modified version of CAPD• Standard manual exchange every 3 to 6 hours• Adventage– Simplicity– Lower cost– Less labor-intense

• Disadventage– Clearance are less– Not be adequate in more catabolic patient

Choosing the dialysis solution

• 1.5% dextrose– Sufficient to remove 50-150 of fluid per hour

(2L ,60min exchange time)– UF rate 1.2-3.6 L/day

• 4.25% dextrose– UF 300-400 ml/hr– Acquired for treatment of CHF

Effect of peritonitis

• During peritonitis– Enhanced absorption of glucose– Rapidly reducing the osmotic gradient

– Maintaining the efficiency of UF • reduced exchange time• More hypertonic exchange

Dialysis Solution additives

• KCl– Hypokalemia KCl 3-5 mEq/L can be added– Correction of acidosis K shift hypokalemia

• Heparin– Catheter obstruction due to fibrin– 1000 U/2 L

• Insulin– Glucose absorbed from the dialysis solution

Insulin

• Antibiotics– Intraperitoneal administration

Monitoring fluid balance

Monitor Clearance

• In general – BUN should maintain below 80 mg/dl

– D:P ratio for urea • [BUN]dialysate : [BUN]plasma ratio• Multiplied by total daily dialysate volume urea daily

clearance• Should be at least 10 ml/min• 20-30 ml/min in hypercatabolic patient


Complications

• Abdominal distention– Incomplete drainage

• Peritonitis– 12% of cases– Occur within first 48 hrs– Gram +ve organisms (>50%)– Prolong used of Multiple antibiotics fungus

• Hypotention– Removal large amout of fluid

Complications

• Hyperglycemia– IP insulin

• Hypernatremia– UF generated in PD [Na] 70 mEq/L– Increased loss of water

• Hypoalbuminemia– Protein loss 10-20 gm /day– Early oral or parenteral hyperalimentation should

be instituted

Adequacy of Peritoneal Dialysis and Chronic Peritoneal Dialysis Prescription





• Choice of modality– CAPD– APD– Variant of APD : CCPD , NIPD– hybrid

• Selection based on– Clearance – UF– Nutritional requirement

Diagrammatic Representation of various

continuous ambulatory peritoneal dialysis and automate peritoneal

dialysis

Modality of peritoneal dialysis therapy

• CAPD– Low cost– Freedom from dialysis machinery– Continuous therapy and a steady physiologic state– Nomalization of blood pressure is possible in most

patients.– Multiple procedural sessions– Can be done away from home– Episodes of peritonitis

Modality of peritoneal dialysis therapy

• APD– CCPD• Continuous therapy• Need for cycler• Complications associated c a prolonged day dwell

– Excessive resorption of dialysate» Icodextrin are useful in day dwell

– NIPD• No dialysis fluid during day time• Suitable for patient with good residual renal function

• Hybrid forms of PD– CAPD with automated nocturnal exchange

• A night exchange device

– APD with additional exchange during the day

• IPD – Almost extinct– Cycler in hospital 2-3 times weekly duration 12-24

hr





CAPD or APD

• Based on– Lifestyle ,emplyment , place of residence comfort

with the cycle technology and family and social support

• Previously APD better than APD– Na Sieving

• Risk of net fluid resorption with long day dwells• Led to concerns about Na removal with APD

– Systolic hypertension with APD > CAPD (no randomized trial but generalizable)

• Risk of peritonitis– Decade ago• APD showed less peritonitis• But APD techinique improved now

• Relative cost





Choice of a prescription

• Clearance targets– ADEMEX study• 1000 CAPD patients

– 4X2 L CAPD versus a high peritoneal clearance regimen – 2 years– Mean Kt/V 1.62 and 2.12 / wk

A concensus target Kt/V for PD 1.7 /wks





Frequency of measurement

• Within 1 month of initiation• And then q 4 months

• Discordance between Kt/V and CrCl– APD• Cr has higher molecular weight than urea





Determinants of clearance

• Residual renal function– Account for as much as 50% of total clearance– Preserved in patient on CAPD

• ACEI ,ARB• Avoid nephrotoxic agents i.e. aminoglycoside

• Peritoneal transport status– PET

• Low transporter high volume ,long duration dwell– Low average– High average

• High transporter short duration dwell

• Body size– Large body size harder to achieve clearance

• Prescription– Change– Focus on lifestyle factors





CAPD

• Initial– 4x2 L or 4x2.5 in larger patients– Increase peritoneal Kt/V in CAPD

• Increasing exchange volumes– Increase backpain– Abdominal distention– Shortness of breath

• Increasing the frequency of daily exchange– Most CAPD pts. Do 4 exchange daily– 45 lead to burn out (alt. night exchange)

• Increase the tonicity of dialysis solution– Increase UF and clearance

APD

• 10-12 L daily (15 L in larger)• Good residual renal function NIPD• High transporter short day time/second

dwell• Typical cycler time is 8-10 hrs – dwell volumes 2 L

Increase clearance of APD

• Introduction of a day dwell– NIPD

• Adding day dwell increase Kt/V and CrCl by 25%-50%• Disadventage

– In high transporter increase net fluid resorption– Icodextrin or shortening day dwell

• Increase dwell volumes on cycler– Because patients are supine during cyclingtolerate

larger dwell volume– 4X2.5 L per session is better than 5X2 L per session

Increase clearance of APD

• Time on cycler– The longer time ,the better clearance

• Increasing frequency of cycles– More frequent cycle increase clearance on APD– But More frequent cycle Dialysis time lost

• Increasing dialysis solution tonicity– concern about glocose-related complications arise

Incremental versus maximal prescription

• Incremental approach– Suitable when dialysis is being initiated early– 2-3 CAPD exchanges daily or a low-volume

– Less costly and less onerous – Decrease total glucose exposure and risk of peritonitis

– Require regular monitoring of resiual function • To ensure that the clearance achieved doesn’t below target

levels

Empirical versus Modeled approach

• Modeled approach• collecting patient anthropometric data , PET , residual

renal function

• Computer program uses the data to predict

• Actual clearance still have to be measure• because discrepancy between actual and modeled

Empirical versus Modeled approach

• Empirical approach– Physician uses knowledge of the patient’s size , residual renal

function , and peritoneal transport status– And choose a resonable prescription

– Advantage• Less trial and error• Earlier identification of an appropriate prescription

Prescription pitfalls in peritoneal dialysis

• Loss of residual renal function– Not monitored closely enough

• Noncompliance– No single test that identifies this problem– Serial measurement of 24-hr dialysate plus urinary Cr excretion

• High serum creatinine despite good clearances– Kt/V > 1.7/wk but serum Cr > 12-15– Non compliance

– Kt/V high and CrCl low– Residual renal function fades away

– Hight lean body mass

• Inappropriate switch form CAPD to APD– Particular in low transporter

• Inadequate attention to fluid removal– Particular in high , high-average transporter and

long dwells that result in net fluid resorption





Nutritional Issues in PD

• nPNA – Normalized protein equivalent of nitrogen appearance– Include

• Serum albumin • Subjective global assessment• Lean body mass

– Measure 24 hr of dialysate and urine (intake output)

– Bergstrom– Recommend 1.2 gm/kg/day

• Caloric intake– = dietary intake + glucose absorbed– 35 kcal/kg/day– 10-30% come from glucose (depend on tonicity)

Bergstrom formulas

• 1) PNA (g per day)=20.1 + 7.5 UNA (g per day)or• 2) PNA (g per day)= 15.1 + 6.95 UNA + dialysate protein

losses (g per day)

• UNA = urinary nitrogen losses (g/day) + dialysiate urea nitrogen losses

• 1) if dialysate protein losses are unknown• 2) if dialysate protein losses are known

Serum albumin

• Strongest predictors of patient survival on PD• Influences – dialysate albumin losses– Inflammation– More than dietary protein intake

Subject global assessment

• Simple clinical tool• Predict patient outcome• KDOQI , Canadian Society

Creatinine excretion

• 24 hr urine and dialysate collections

Treatment of malnutrition

• Dietitian support– Dietition to ensure adequate protein intake

• Nutritional Supplement

• Promotility agent– Gastric emptying is impaired

• Anabolic steroid– 1 RCT ,Nandrolone 100 mg IM weekly for 6 months improve

lean body mass • Amino acid

– amino acid based dwell

Health & Medicine

PD prescription