Peritoneal Dialysis Adequacy

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Peritoneal Dialysis Adequacy Prescription
Management
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Background

• Target small solute clearances have been based
  upon assumptions that peritoneal and renal
  clearances are added together
• Renal small solute clearances are directly
  correlated with patient survival
• There have been no randomized, controlled
  interventional trials examining the role of
  increases in peritoneal small solute clearances
  on patient survival

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Improving patient lifetime on therapy
Access
Adequacy
QoL
Fluid control
Nutrition
Compliance
Infection control
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Components of Prescription Management
Fixed Parameters
Adjusted Parameters

• Disease Process
• Lifestyle
• Body Size
• Residual Renal Function (RRF)
• Peritoneal Membrane

• Fill Volume
• Number of Exchanges
• Dwell Time
• Efficient Use of Total 24 Hours
• Glucose Concentration

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Adequacy Targets have changed over the last decade

• Creat.clr KT/V (l/week)
• In 1992 40 1.5
• In 1995 50 1.7
• In 1997 60 2.0
• In 1999 60 2.0 (high-avg/high
  transporters) 50 (low/low-avg
  transporters)
• In 2001 50 1.7
• Ultrafiltration starts to get an increased focus
  compared to earlier 1L total water removal/day

European PD guidelines, published 2001
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What is Clearance?

• Clearance is the total amount of body fluid
  completely cleared of a solute during a certain
  time
• ml/min
• L/week
• Ex Creatinine clearance 50 l/week means
• 50 L of body fluid is totally cleared for
  creatinine during a week

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Targets for solute clearance
Suggested impact on outcome
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The peritoneal equilibration test (PET)

• Semiquantitative assessment of peritoneal
  membrane transport function
• Assess rates of solute equilibration between
  peritoneal capillary blood and dialysate
• Uses the ratio of solute concentrations in
  dialysate and plasma (D/P) at specific times to
  signify the extent of equilibration
• Performed using a standardized method, using
  standard solutions (2.27 glucose)

Twardowski ZJ, Nolph KD, Khanna R et al Perit
Dial Bull 19877138.
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Clinical applications of the PET

• peritoneal membrane transport classification
• predict dialysis dose
• choose peritoneal dialysis regime
• monitor peritoneal membrane function
• diagnose acute membrane injury
• diagnose causes of inadequate ultrafiltration
• diagnose causes of inadequate solute clearance
• estimate D/P ratio of a solute at a particular
  time

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The peritoneal equilibration test (PET)

• following a standard overnight exchange
• drain to dryness
• instill 2.27 2000 ml glucose bag
• roll patient to ensure mixing
• sample PD fluid at time 0, 2, 4 hours
• blood test (assume blood concentrations constant)
• drain out at 4 hours and measure drain volume

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The peritoneal equilibration test (PET)
Drain volumes correlate positively with dialysate
glucose and negatively with D/P creatinine at 4
hours
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Membrane transport type.
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Calculation of Peritoneal Urea Clearance
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Calculation of peritoneal urea clearance
0.288 x 7 2.02
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Calculation of Peritoneal Creat. Clearance
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Calculation of Peritoneal Creat Clearance
10.7 x 0.788 x 7 59 l/wk
Normalise to BSA CCl x 1.73/ patients BSA
Normalised weekly CCl 59 l/wk/1.73 m2
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A standard patient?
2.0
10 l
1.0
35l
0.286 x 7 2.0
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Optimizing peritoneal dialysis dose
Schedule dwell times to maximise clearance
Increase dialysis dose by increasing drain volumes
Problems arise for large body weights
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Treatment guidelines a summary

• Patients with BSAgt 1.7m2 or body weight gt65 kg
• Routinely prescribed 2.5L fill volume
• Patients with BSAgt 2 m2 or body weight gt80 kg
• Routinely prescribed 3 L fill volume
• Patients requiring 5 day exchanges should use a
  night time exchange device to deliver the 5th
  exchange
• Patients on APD should do one or more day time
  exchanges (unless small BSA or high RRF)

Clinical Practice Guidelines of the Canadian
Society of Nephrology for treatments of Patients
with CRF JASN 10 S287-S321, 1999
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Main principles behind the APD guidelines

• Patients with higher D/P require an increased
  number of exchanges during the night
• Patients with higher BSA require higher fill
  volume per exchange
• Anuric patients are advised to have an extra day
  exchange (OCPD)
• Extraneal is encouraged to be used in all
  patients during a long day well as it can
  improve the UF and clearance of patients

Increase number of exchanges
Increase fill volume
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Overview of guidelinesRRF gt2 ml/min
All prescriptions include 9 hours overnight
treatment. If targets are over achieved,
reducing therapy time at night can be an option.
Monitor with care Varied glucose concentrations
and Extraneal are advised to use in order to
meet the required UF of min.1 L
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Overview of guidelines RRF lt2 ml/min
All prescriptions include 9 hours overnight
treatment if not otherwise noted Varied glucose
concentrations and Extraneal are advised to use
in order to meet the required UF of min.1 L APD
For these patient groups, APD therapy will
probably not reach both KT/V and Creat clr.
targets. Monitor with care. Two day time
exchanges can be beneficial for motivated
patients in order to meet targets.
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Impact of larger CAPD volumes on total CCl
versus a 5th exchange (calculated).
Assume 70 kg male, anuria, 4 hr D/P 0.65, BSA
1.73m2, 2l UF.
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Relationship Between Dwell Time and Transport
Transport Solute Cl UF
Prescription Rapid Short
dwell High A CAPD/CCPD Low A
CAPD/CCPD Low Long
Dwells gt Always maximize fill volumes
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Common prescription errors - CAPD

• mismatch dwell time and transport type
• inappropriately short daytime dwell
• inappropriate infused volumes
• inappropriate glucose concentration for nighttime
  dwell

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Common prescription errors - APD

• inappropriate use of a dry day
• inappropriately long drain times
• failure to increase target dose to account for
  intermittent therapy
• failure to consider a CAPD exchange during the
  day to increase clearance

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ADEMEX

• ADEMEX (ADEquacy of PD in MEXico) is a
  randomized, active controlled, prospective trial
• Hypothesis tested increases in peritoneal
  clearance of small solutes improves the PD
  patients survival
• The primary outcome was mortality.

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ADEMEX Summary of Design

• Patient Numbers
• 965 Mexican patients current or new to dialysis
  from 24 participating centers were randomized
• 484 Control
• 481 Treated
• Initial recruitment started on June 1, 1998
• First patient randomized July 9, 1998
• Follow-up through May 6, 2001
• A minimum follow-up of two years following
  enrollment

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Study Design
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ADEMEX Treatment Characteristics
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ADEMEX Treatment Characteristics
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ADEMEX Primary Outcome
p0.9842
Patient Survival
RR(TreatedControl)1.00 95 CI
(0.80, 1.24)
Months on Study
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ADEMEX Conclusions

• There was no difference in patient survival with
  variations in peritoneal small solute clearance
  within ranges achievable in current clinical
  practice.
• Survival remained similar between the two groups
  even after adjusting for factors known to be
  associated with mortality in patients on PD (age,
  diabetes, albumin, nPNA, anuria)

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Recommended Total SoluteClearance Targets
CAPD Kt/V CCr/1.73m2 NKF-DOQI 1997
2.0 60 L NKF-DOQI 2000 LLA 2.0 50
L HAH 2.0 60 L Canadian guidelines L
LA 2.0 50 L HA H 2.0 60 L Renal Assoc -
UK 1.7 50 L EDTA-ERA 1.7 (Peritoneal)
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Prescription Modification
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Prescription Modification
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Prescription Modification
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Prescription Modification
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Prescription Modification
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APD - Increasing Clearance

• Increase fill volumes
• Add a daytime exchange
• Increase Time on Cycler
• Increase Number of Nighttime Exchanges

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APD - Increasing Clearance

• Increase fill volumes
• Effective means of improving clearance
• Minimum impact on patient lifestyle
• Adjust nighttime exchanges first
• Use 2.0L or greater whenever possible
• Add a daytime exchange
• Increase Time on Cycler
• Increase Number of Nighttime Exchanges

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APD - Increasing Clearance

• Increase fill volumes
• Add a daytime exchange
• This is a very effective means of improving
  clearance
• HomeChoice can be programmed to deliver the
  midday exchange
• Increase Time on Cycler
• Increase Number of Nighttime Exchanges

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APD - Increasing Clearance

• Increase fill volumes
• Add a daytime exchange
• Increase Time on Cycler
• Cycler time can be extended to 10 hours
• Increasing cycler time with a constant number of
  exchanges increases dwell time which increases
  clearance
• Increase Number of Nighttime Exchanges

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APD - Increasing Clearance

• Increase fill volumes
• Add a daytime exchange
• Increase Time on Cycler
• Increase Number of Nighttime Exchanges
• May increase clearance, but only if time on
  cycler is also increased

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Solute Control Algorithm
Initiate Therapy
Measure Clearances
Adjust Therapy
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Monitoring frequency

• KT/V and Creat.clr
• Within 6-8 weeks after commencing dialysis
• Every subsequent 6 month
• If patients clinical status changes unexpectedly,
  or if prescription is altered, take supplemental
  clearance measurements
• PET
• Within 6 weeks of initiating PD
• Repeat if unexpected changes in peritoneal UF
  occur

Clinical Practice Guidelines of the Canadian
Society of Nephrology for treatments of Patients
with CRF JASN 10 S287-S321, 1999
47
Making monitoring of adequacy easier

• Using a software program makes monitoring easier
• Automated calculations of creat clearance, KT/V,
  nPNA
• Reporting function gives easy overview of one
  patient or whole patient population
• Easy to identify problem patients where actions
  might be needed
• Track and document improvements over time

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Auditing clinical outcomes in PD

• Monitor patient and technique survival in all
  large programs
• Monitor of patients in all PD programs who fail
  to achieve targets
• Record of patients in all PD programs with
  inadequate nPNA values and severe hypoalbuminemia
• A good program will have 80-85 of patients
  achieving adequacy targets
• Review the proportions of patients exceeding
  targets every 3-6 months

Clinical Practice Guidelines of the Canadian
Society of Nephrology for treatments of Patients
with CRF JASN 10 S287-S321, 1999
49
Conclusion.

• There is uncertainty about the target clearance
  in PD
• Patient management in peritoneal dialysis
  involves much more than small solute clearance
  of particular importance are for example residual
  renal function and ultrafiltration volume, as
  well as the other complex of factors central to
  holistic management of renal failure patients.