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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
• Peritoneal dialysis prescription– Acute• Introduction• Peritoneal Catheter• Use of automate cycler• Prescribing acute peritoneal dialysis• Complications
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 dialysis prescription– Acute• Introduction• Peritoneal Catheter• Use of automate cycler• Prescribing acute peritoneal dialysis• Complications
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
• Peritoneal dialysis prescription– Acute• Introduction• Peritoneal Catheter• Use of automate cycler• Prescribing acute peritoneal dialysis• Complications
Use of automated cyclers
• Traditionally been done using manual exchanged
• Automated cyclers are being used instead– Saving nursing time (30-60 minutes exchange time)
• Peritoneal dialysis prescription– Acute• Introduction• Peritoneal Catheter• Use of automate cycler• Prescribing acute peritoneal dialysis• Complications
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
• Peritoneal dialysis prescription– Acute• Introduction• Peritoneal Catheter• Use of automate cycler• Prescribing acute peritoneal dialysis• Complications
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
• 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
• 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
• 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
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
• 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
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
• 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
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
• 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
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
• 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
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
• 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
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