Q.636. How to choose of P. D. modality?

 

PERITONEAL DIALYSIS

Q.636. How to choose of P. D. modality ? 

 

Most ptn. on maintenance PD need continuous DX é CAPD or CCPD to achieve adequate weekly solute clearances. CAPD cn be used, é typical minimum DX of 4, 2 L. exchange/d., include one overnight exchange. Standard reg. cn be modified by changing either dwell time, volume or No. of exch./d. Exch. are performed manually. CCPD is an automated form in wch a cycler delivers 3-6 exchange while ptn. sleeps é  12-15 h. daytime dwell. Weekly clearances are similar to CAPD but more Dzt fluid is required each day. U.F. rates may be lower é automated forms of thpy. We us. let ptn. choose betw. CAPD & CCPD based upon lifestyle or personal issues (desire to work, wish to not do any exch. dur. day, or, in a ptn who is not able to do exchange themselves). CCPD provided signif. more time for work, family & social activities thn CAPD. Sleep apnea may be more responsive to NPD. Further recomm. are made after DX dose hs bn documented é 24 h. Dzt collection for volume & Cr. Cl. or Kt/V, or it’s determined fr. PET test. Ptns should be monitored for loss of Kru. Fall in solute clearance can usually be reversed by 🠝DX dose via an 🠝dwell volume or No. of exchange/d.. Either of these modalities will 🠝 net Dzt flow rate, thereby 🠝clearance of urea & other small solutes by keeping concentration gradient for solute diffusion . APD is superior to CAPD in optimizing fluid & Ssc in some ptns. This’s because automated techniques can combine larger dwell volume, long noctur-nal sessions, and add daytime exchange, thereby moderately 🠝 solute & fluid removal.

Body surface area: In addition to transport type, Kru & life style, another f. to consider é prescribing PD is BSA, as both Kt/V & weekly Cr.cl. must be normalized to  👉body size. An absolute Cr.cl. of 60 L/w. represents different degrees of dialy-tic solute removal in small vs large ptns. Large ptn typically need high Dzt. volume, especially é slow transporters & have no Kru. é CAPD, dwell vol. is typically 2.5-3 L. & some ptns require 5 exchange/d..In CCPD, ptn. us. need 12-14 h. of dwell time while on the cycler, using large instilled vol. of Dzt; an alternative is: shorter cycler time (9-11 h.) +1-2 day-time exch.. A large instilled vol. usually required é daytime dwell & some ptn. need to perform one manual CAPD exch. to meet the goal for Ssc. However, 🠝 nightly Dzt flow may be superior to adding manual daytime exchange.

Intermittent PD: hs evolved as we have better ability to match dwell time & vol. to transport ch.ch. Rapid transporters, do best é short dwells & may initially achieve adequate clearances é "dry" day option on CAPD. However, they may need to change their prescription to IPD if they lose their Kru. If NIPD is used é 8-12 h. DX, the dwell time may be only 1-2 h./exch. é 1.5-2.0 L dwell vol.s. This requires 8-20 L. of Dzt fluid/d.. Adequate solute clearances cn be achieved é this reg. even though ptn. hs a "dry" day. However, unless Kru is signif., most ptns need a "wet" day. 10-15 % of ptn might do best é NIPD or daytime DAPD. DAPD is similar to NIPD except tht exchanges are performed manually duration the day. Classic IPD: a form of DX. in wch multiple short exch. are performed on inter-mittent basis. A typical reg. of 12-15 two L., one h. dwells performed 3-4 d./w.. Over 50 h. us. required to attain clearances similar to CAPD. However, higher target doses of DX are recommended because of the peaks in BUN occur on off-DX d.s. For these reasons, this form of PD is not recommended for chronic use.

Q.637. Can you please summarize ur choices?

A. Different techniques are currently available for P.D. CAPD involves multiple exchanges per d. (us. 3) following by an overnight dwell. APD refers to techniques that use an automated device to do multiple exchanges overnight with or without a daytime dwell such as CCPD, NIPD & TPD. Of these, 👉 CCPD🠞most commonly used, it has a long daytime dwell + several cycles overnight. We usually let the patient choose his modality (most commonly CAPD or CCPD) based upon lifestyle or personal issues since the choice is unlikely to matter as far as achieving Kt/V & UF goals, as most ptn initially hv significant Kru .

Prescription hs to be modified by time, due to loss of renal function. The principal f. tht determine optimal PD prescription are “membrane transport type”, degree of Kru, life style choice & BSA. In general, APD is recommended for rapid transporters; low transporters who desire to continue with APD will likely require a midday exchange to achieve adequate fluid/solute removal.

Q.638. What are your tools to reach U.F. target in P.D.?

   A. Two ✌ important tools:

       1. “Icodextrin”= “Extraneal” = “Glucopolymer” 🠞é U.F., S.E. 🠞 Wt. gain.

       2. Dextrose conc. %:    - 1.36   for “Low” U.F.

                                         - 2.27   for “moderate” U.F.

                                         - 3.86      ,,     ,,      ,,.

                                         - 4.25    for “High” U.F.

Q.639. What is the target Kt/V. for A.P.D. & CAPD.?

   A. Target Kt/V.: * A.P.D.  🠞  2.1 /w

               👌         * CAPD. 🠞  1.9 /w.

                                * Cr. Cl. 🠞  60  L/ 1.73 m2 B.S.A.

Q.640. Why Kt/V & creatinine clearance may not be correlated in continuous P.D.? 

A. Until now the best yardstick for P.D. adequacy remains to be determined. Whereas prev. recommended suggested: use of either urea or cr. kinetics, 2006 NKF-K/ DOQI G.L. recommended: Kt/Vurea target (ie, urea kinetics) only. Although Cr. cl. & Kt/V us. correlate, they’re not infrequently discrepant. Both DX. & Kru affect both Cr. Cl. & Kt/V. Ratio of Cr. Cl.-to-Kt/V is higher in ptn é Kru & falls if he became anuric.

Ch.ch. of Pr. membrane transport may affect the relationship between Cr. cl. & Kt/V. For shorter dwells, esp. in low transporters, urea clearance per dwell exceeds tht for Cr.. Whereas weekly Kt/V is independent of transporter type, weekly Cr. Cl.🠟 progressively from high to low transporters. It’s important to be aware of Pr. membrane transport ch.ch. of individual ptn when writing PD prescription & interpreting solute clearance results. Ptn wt hs a greater effect on Kt/V thn on Cr. Cl.. {A dcrease or increase in wt 🠞 Kt/V to increase or dcrease, resp.}. So, Kt/V is often at or above target values in malnourished ptn & low in obese ptn. Using the desired rather thn actual wt 🠞more accurate results.