Smart APD prescription. Prof. Wai Kei Lo Tung Wah Hospital The University of Hong Kong

Transcription

1 Smart APD prescription Prof. Wai Kei Lo Tung Wah Hospital The University of Hong Kong

2 Costing Comparison of Different Modes of RRT in Hong Kong in 2011 (Per Year) HK$300,000 HK$250,000 HK$200,000 HK$150,000 HK$100,000 HK$50,000 HK$0 Hospital HD HD PPP NHHD (First Year) NHHD (Subsequent Years) CAPD APD (First Year) APD (Subsequent Years) Patient Payment Charity Funded HA Funded (Pathology, pharmacy and radiology costs of hospital HD in HA excluded)

3 APD is an expensive treatment Extra expenditure of APD over CAPD Machine cost HKD 84,000 Daily disposed consumables PDF line HKD 100/day PDF : usually consume 2-3 liter of PDF more than CAPD due to reduced efficiency in clearance Patients converted from CAPD to CCPD for inadequate clearance / UF often require higher volume of PDF Priming volume of PDF for the lines ~ 300 ml

4 Cost: APD vs CAPD Apart from cost of machine and consumables Uses more PDF to achieve same clearance and UF, i.e. PDF less cost-effective than CAPD CAPD APD P BW, kg / / NS Total vol, L/day 8.5 +/ / Icodextrin use 9.5% 53.8% Peritoneal CrCl / / NS UF, ml/day / / Rodriguez-Carmona A. PDI 2002; 22:705-13

5 Reasons for reduced efficiency of clearance in APD Reduced efficiency in short nocturnal cycles in small solute clearance PDF is still far from equilibrium when drained out Negative UF commonly seen in long day dwell, resulting in lower clearance despite full equilibrium Icodextrin PDF is often needed for the long day dwell to achieve UF The problem of break point of each cycle

6 One more reason for reduced efficiency with frequent short dwell cycles - concept of Break Point Break point Duration of reduced clearance rate ~ 15 minutes per cycle

7 Effective dialysis time during nocturnal cycles For each cycle there 15 minutes of inefficient clearance Scenario 1 : 9 hours overnight with 2L x 3 cycles Leaving the effective dialysis time = 540 (15 x 3) minutes = 495 minutes The effective dialysis time % = 495/540 minutes = 92% Scenario 2 ; 9 hours overnight with 2 L x 5 cycles Ineffective dialysis time = 15 min x 5 cycles = 75 minutes The effective dialysis time % = (540-75)/540 = 86% If patient has slower drain, the inefficiency is even larger

8 The more cycles at night, more drain-fill time wasted Mujais S. Contrib Nephrol, 1999; 129;

9 Smart APD prescription Achieve adequate dialysis Achieve adequate ultrafiltration Achieve adequate sodium removal in a cost-effective way! and minimally affect patient's social life

10 Making APD cost-effective In the western world, cost is not a concern, many patients were prescribed with 15 liter PDF, which is a big $$$ Does patient need that much?

11 How to achieve better clearance (Kt/V) with less PDF used?

12 We can estimate the clearance or Kt/V urea from patient's PET data - D/P urea Twardowski ZJ. PD Bulletein 1987 NDT 1998; 13(S6):

13 Adequacy of dialysis (Kt/V) in APD Daily Kt/V peritoneal = D/P urea x effluent volume 24 hr / TBW Daily Kt/V peritoneal = (D/P day x EV day + D/P night x total EV night ) / TBW EV = effluent volume

14 Estimating the D/P urea of each bag Transport type Low Low Average High average High 1 hour hour hour hour

15 Let s start with nocturnal cycles prescriptions Usual night time connection to APD time between 9 10 hours, e.g. 10 pm to 7 am Allow some free time after dinner for family, social function or personal activities

16 Effect of peritoneal transport on Kt/V delivered An example: 3 hour effective dwell, 60 kg, TBW 35L total nocturnal dwell time = 3 hr x min x 3 = 9 hr 45 min Low Low Avg High Avg High D/P urea 3 hrs UF, ml EV / cycle, L cycles TBW daily Kt/V weekly Kt/V High transport patients have slightly higher Kt/V achieved EV = effluent volume

17 From 3 4 cycles over 9 hours (using 1/3 more PDF volume) Effective dialysis time = 540 (15x4) = 480 minutes = 120 min/cycle ~ 2 hr/cycle Low Low Avg High Avg High D/P urea 2 hrs UF/cycle, ml EV / cycle, L cycles TBW daily Kt/V weekly Kt/V 0.88 (0.97) 1.12 (1.01) 1.26 (1.12) 1.39 (1.19) % increase from 3/night -9% 10% 13% 17% High and high average transport patients have significantly improved Kt/V but less than 1/3 gain Low average transport patients had very small gain, AND Low transport patients have little gain or even loss

18 High transporters Cycles /night hours/cycle Total hours D/P urea UF, ml EV / cycle, L Total EV, L/day TBW daily Kt/V weekly Kt/V Total PDF used, L Kt/V per L Very high Kt/V can be achieved by multiple short cycles But cost-effectiveness reduces slightly peritoneal Kt/V above 1.7 can be achieved with around 5 cycles/night

19 Higher Kt/V can be considerably achieved with multiple short cycle by cost-effectiveness is lower than high transporters If renal Kt/V is low, need Kt/V from day dwell High average transporters Cycles /night hours/cycle Total hours D/P urea UF, ml EV / cycle, L Total EV, L/day TBW daily Kt/V weekly Kt/V Total PDF used, L Kt/V per L

20 Low average transporters Cycles /night hours/cycle Total hours D/P urea UF/cycle, ml EV / cycle, L Total EV, L/day TBW, L daily Kt/V weekly Kt/V Total PDF, L Kt/V per L Difficult to achieve adequate Kt/V with NIPD alone unless RRF is very high Cost-effectiveness further reduced with high frequency exchange

21 Low transporters Cycles /night hours/cycle Total hours D/P urea UF, ml EV / cycle, L Daily EV, L TBW daily Kt/V weekly Kt/V Total PDF used, L Kt/V per L increasing the number of cycles only marginally increase Kt/V And cost effectiveness greatly reduces NIPD not good for low transporters

22 Efficiency of dialysis Kt/V per liter achieved Hours/cycle Cycles/night High High avg Low avg Low Shortening the cycle in low transporters reduces the efficiency of dialysis tremendously

23 adjusting volume in low transporters provides better cost-effectivenes hours/cycle cycles Total hours Dwell vol, L D/P urea UF, ml EV / cycle, L Daily EV, L TBW, L daily Kt/V weekly Kt/V Total PDF used, L Kt/V per L Efficiency of PDF not much affected,

24 The maximal dwell volume There were recommendations that the supine intraperitoneal pressure in APD should not > 17 mmhg (usually 5-15) (23 cm H 2 O) because it will exceed the capillary hydrostatic pressure affect peritoneal capillary perfusion, solute and water transport Best be kept below 18 cm H 2 O Dwell volume 1500ml/m 2 consider optimal Durand PY. Contrib in Nephrology 1999, 2006

25 Max Fill volume with HomeChoice 2010 September

26 Max Fill volume 2L for >47 kg 2.5L > 59 kg 3.0L for > 70 kg Measure intraperitoneal pressure if you have doubts, or patient is uncomfortable with the dwell volume

27 Day Dwell The day dwell time is often around hours D/P urea ~ 1.0 UF can be very variable Often negative ultrafiltration in high and high average transport patients They may absorb up to 500 ml!

28 Kt/V achieved in day dwell (2L) D/P = 1 EV weekly Kt/V High transport 1.5 L 0.3 High average 1.8 L 0.36 Low average 2 L 0.40 Low 2.2 L 0.44 If icodextrin is used, EV = 2.4 L Kt/V= 0.48

29 Cost effective prescription of PDF High transporters Adding nocturnal cycles Or use icodextrin in day dwell Others, particularly low transporters Either increase the volume of dwell, or Adding a day dwell Providing that UF is not a problem

30 UF in APD UF is mainly achieved through the nocturnal cycles In general: more frequent cycles better the UF Higher concentration PDF better the UF Daytime UF NIPD no UF in day time CCPD often negative UF with the long day dwell, particularly in the high and high average transporters, may absorb 500ml Only low transporters can have positive UF in day time

31 Another consideration Sodium removal in APD In the first 1-2 hours of a dwell, water transport by osmosis is faster than sodium because of the presence of aquaporin (ultra-small pores) allows only water but not sodium to pass through Producing sodium sieving effect Most obvious when using 4.25% PDF

32 Sodium removal in APD Sodium removal in APD is usually less than CAPD patients, particularly when multiple short cycles are used at night time For any given UF achieved, Na removal is less with APD than CAPD Rodriguez-Carmona A. PDI 2002; 22: & AJKD 2004; 44(1):132-45,

33 Sodium removal in APD Thus if only water balance is monitored, the patient is at risk of sodium retention and hypernatremia, Serum sodium has to be monitored Patients should be advised on low salt diet particularly in NIPD patients when multiple short cycles high concentration PDF is used

34 Achieving adequate sodium removal In the first 1-2 hours of a dwell, water transport by osmosis is faster than sodium because of the presence of aquaporin (ultra-small pores) allows only water but not sodium to pass through Producing sodium sieving effect Most renown when using 4.25% PDF But no such effect with icodextrin PDF (no enhanced water transport through aquaporin) Water movement is through large and small pores, which also allow Na to move together with water

35 Sodium sieving effect with different solutions 1.5% icodextrin 4.25% 4.25%

36 To improve day time UF and Na removal problem If we can improve UF in day time, then patients not so much dependent on UF at night time Less high concentration PDF is used less glucose exposure Icodextrin day dwell is the best solution

37 Icodextrin helps both UF and Na removal for the long day dwell for most patients Simulation based on 3-pore model of peritoneal transport by PD Adequest 2.0 Akonur A... Sloand J. PDI 2016; 36:79-84

38 Weekly Kt/V achieved (nocturnal 10L 2.27% over 10 hours) Day time regime Akonur A. PDI 2013; 23: Adding one more day exchange cycle increases Kt/V better But at the compromise of patient s life style

39 24 hr UF achieved (nocturnal 10L 2.27% over 10 hours) Akonur A. PDI 2013; 23:

40 24 hr Na removal achieved (nocturnal 10L 2.27% over 10 hours) Akonur A. PDI 2013; 23: Whether the patient can perform one more exchange in day time is another concern

41 Kt/V and UF achieved with 2.5% day dwell a function of time Akonur A. PDI 2013; 23:

42 Optimal dwell time 2.27% PDF Peak dwell time, hrs UF Kt/V Optimal dwell time High High Average Low Average Akonur A. PDI 2013; 23:

43 Achieving adequate dialysis and UF in a 70 kg anuric APD patient PET Nocturnal regime nocturnal Kt/V Day time regime High 2L x L icodextrin High avg 2L x L icodextrin day time Kt/V Total Kt/V Total UF = 1.2L = 1L Low avg 2.6L x L = 0.75L Low 2.8L x L = 1.1L (2.5%) Total PDF vol 10 L 10 L L 70 kg - max dwell volume 3L Nocturnal APD time can be increased to hours for longer dwell cycles or more frequent cycles Can add one more day exchange to achieve higher clearance for very heavy patients

44 Akonur A... Sloand J. PDI 2016; 36:188-95

45 Simulated model to achieve adequate clearance and UF Big size, V> 42L, RRF < 2ml/min/1.73m 2 Low High Night 3 x 3L (1.5%/2.5%) 5 x 2.5L (1.5%/2.5%) Day 2x 3L (2.5%) 2.5L icodextrin x 1 Akonur A... Sloand J. PDI 2016; 36:188-95

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48 Variable cycles 12 L over 9 hours in both regime UF improved by 15% Fischbach M. PDI 2011; 31:450-8

49 My practice Most new patients have significant RRF Therefore start with NIPD 3 cycles over 9 hours, measure Kt/V and PET most patients will get a Kt/V ~ (70kg) If dialysis is inadequate, then consider increasing the nocturnal cycles or adding day time dwell --> CCPD, according to PET use icodextrin for high and high average transporters, unless patient has lots of urine

50 M/62 3/2010 3/2012 9/2012 2/ /2013 4/2014 4/2016 BW, kg Regime (night) CAPD CAPD CCPD CCPD CCPD CCPD CCPD 2L x 3 + (Day) (Day) 2L 7.5% (night) 2.5Lx 3 (Day) 7.5% 2L (night) 2.5L x 4 /10 hrs 7.5% 2L (day) ditto 2.5L 2.5% x5 12 hours 7.5% 2L ditto ditto 7.5% 2L 7.5% 2L ditto PDF, L UF pkt/v tkt/v CrCl RRF, urine D/P Cr pkt/v per L

51 M/70 8/2011 2/2012 7/2012 7/2013 7/2014 4/2015 BW, kg Night regime NIPD NIPD CCPD CCPD CCPD CCPD 2.2L 1.5% x 3 2L 1.5% x 3 2L 1.5% x 3 2.5L 1.5% x 3 2.5L x 3 (1.5% 6L + 2.5% 2L) 2.5L x % Day 2L 1.5% 2L 7.5% 2L 7.5% 2L 7.5% PDF L UF pkt/v tkt/v CrCL RRF, urine D/P Cr pkt/v per L

52 To make it simple Do not blindly increase the number of exchange at night time to increase clearance OK for high transporters consider increasing the dwell volume instead of frequency for low transporters Adding day time dwell or day time exchange is more efficient to increase clearance But need to consider life style impact Day time icodextrin dwell increases UF, clearance and Na removal

53 Smart!!