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HEMODIALYSIS

Q.618. What is the effect of catheter type on the incidence of recirculation? C

 

HEMODIALYSIS

hemodialysis complications hemodialysis meaning hemodialysis machine hemodialysis procedure hemodialysis and peritoneal dialysis


ESRD ptns are particularly vulnerable to severe COVID-19 (older age & high frequency of co-morbidity, e.g. DM & HT, in this cohort. The ASN & ISN hv issued guidelines and a list of resources to guide nephrologists to provide life-sustaining DX care. These resources that continue to evolve are frequently updated, including the following: early recognition & isolation of individuals with respiratory Sm(s); ptn separation & cohorting within waiting areas and within DX unit; use of personal protective equipment in DX unit; with added measures for ptns with confirmed/suspected COVID-19.  

Q.618. What is the effect of catheter type on the incidence of re-circulation?  🗘


 A. Recirculation:

                         i.    Dcr. if the length of femoral cath. ³ 19 cm.

                        ii.    Highest é femoral catheter compared to central catheter.

                       iii.    Incr. é in blood pump(Qb.) (reaches 50% é Qb. of 300).

- A “split 👍 catheter” é Qb. of 400 ml/min. mean recirculation rate = (1.3- 4.9%).

Q.619. How to be careful for this access?     

A. Malfunction can occur due to either:    i. Thrombosis.

                                                     ii. Fibrin sheath,  So, 👉

-      Line reversal (switch) 🗘is accepted é accepted recirculation rate. 🗘

-      Local A.B. ointment or dry gauze é exit site decrease infection rate.

-      Cth. dur.(Ÿ3 w.) increase liability for infection, so, 1st line Cth. removal.

-      Q/DOKI recommendations (Cath. care No.15), see next Q.

Q.620.What are the Q/DOKI recommendations for catheter care?

A. Q/DOKI  recommendations (Cath. care No.15    

1)           Internal jugular  Low infection & recirculation rates, most preferable.

2)           Internal juguler & Rt. subclavian: 15-20 cm. Lt.: 20-24 cm. Femoral: >19 cm.

3)           Avoid subclavian, apply femoral for bed-bound, single use é CHF.

4)           Duration: one w. for femoral(2-3w. for Silicon cth.) & 3 w. for I.J.

5)           Exit care: Dressing, dry gauze, povoidine, I2 oint., sterile technique :  (gown, gloves, mask….).

Q.621. Explain how could the variation in CRRT modalities expand its spectrum?

A. CRRT  🠞Continuous fluid & solute removal:

[SLEDD] 🠞Slow Low Efficiency Daily Dialysis.

[SCUF] 🠞 Pure convection, No Dzt, No S.F., only U.F. (used é modest U.F.). A simple bld system é high flux 🠞U.F. only, limited to input. So, not suitable for azotemia & Kru shd be present.

[CVVH]🠞[U.F.+ S.F. + No Dzt]: High vol. U.F. & metabolic control, so requires S.F.

[CVVHD]🠞[U.F.+ Dzt+ No S.F.]: Low efficiency, limited Dzt. vol. (1-3) L.(2L./ h.).

 [CVVHDF]🠞[U.F.+ Dzt+ S.F.].

Q.622. What is difference between I.H.DX. & CVVHD?

A. CVVHD 🠞[U.F.+ Dzt.+ No S.F.]: Low efficiency, limited Dzt. vol. to 33 ml/ min. (1-3) L. (2L./h.)… While I.H.Dx. Q.D.🠞500-800 ml/min.(30-48) L/h. & Q.B.= 200-500 ml/min. If bicarbonate module is added 🠞better outcome.

Q. 623. What clearance benefits can CVVHDF provide?

A. CVVHDF provides “combined clearance”:

{ Diffusive (Dzt) + Convective clearance (U.F.) = Augmented Clearance.}

Q.624. What is the effect of choosing “pre-dilution” & post-dilution in CVVHD modality?

A. Pre-dilution🠞Reduces clearance by 15%, but it is beneficial in dcr. Hemoconcentration 🠞less liability for thrombosis.

  Post-dilution🠞increased liability for thrombosis, but more clearance is expected.

Q. 625. How to prescribe SLEDD? What is its advantages?

A.  R  /       SLEDD:        Q.B. : (200-300) ml/min.

                                     Q.D.: (100) ml/min.

                                Duration: (8-12) h.

 - SLEDD hs bn developed to be a hybrid  هجين   between continuous & intermittent therapy, it hs the foll. advantages:

                                                         i.    More hemodynamic stability.

                                                        ii.    Increased clearance compared to convective thpy.

                                                       iii.    Time off D.X. for diagnostic procedures.

                                                       iv.    Done by I.C.U. staff  & by ordinary staff.

Q.626. Compare P.D. to CRRT? Mention advantages & disadvantages?

A. P.D. needs: [Intact peritoneum + P.D. cth. (Tenckhoff)].  

- Clearance by:    i. Diffusion.    ii. Convection.

- P.D. is inferior to CRRT in:  i. Sepsis.       &  ii. Malnutrition, but:

- P.D. hs the foll. advantages:        

1)   Simple system.

2)   Inexpensive.

3)   Lack of anticoagulation.

4)   Hemodynamic stability.

5)   No vascular access troubles.

- By increased frequency of exchange & conc. of dextrose  8 Adjust quality & quantity of U.F. However, P.D. has many disadvantage, see next Q.

Q.627. Then what is the disadvantages of P.D.?

A. P.D. hs many disadvantage:      

1)   Hyperglycemia & Wt. gain.

2)   Risk of peritonitis.

3)   Need for intact peritoneum.

4)   Less clearance compared to SLEDD & CRRT.

5)   Respiratory embracement ( increased intra-abdominal pressure).

Q.628. What is the Equal Renal Clearance (EKR)? What is its significance?

A. EKR: In a 70 kg é 10 kg overload, BUN: 90 mg/dl., ERK c [Urea, Inulin, Amylase & B2 microglobulin] clearance (6 d/w.)  c  

                     CVVH : (3 L/h., pre-fluid Dzt-dilution)  c  =  33.

                    SLEDD (12 h./7d./w., Q.b.: 300, Q.d.: 100 ml/min.)c 31.

                   ƒ I.H.D. (4 h., Q.b.: 350 ml/min., Q.d.: 600 ml/min.) c  21.

Q. 629. What is the effect of dose of therapy in CRRT modalities on patient survival?

A. Ronco et al, used (Lactate-based) post-filter CVVH é different replacement fluid rates (S.F.): 20, 35, 45 ml/kg/h. é delivered U.F. rate of 31, 56, 68 L/d. The highest survival in 35 (57%)  & 45 (58%) ml/kg./h. (S.F.). [Ronco C., e al, Effects of different doses of CVVH on outcome of acute renal failure. A prospective randomized trial, Lancet, 365:26-30,2000].

Generally, during COVID-19 pandemic, ptns receiving home DX should hv their regular follow-up visits performed via telemedicine rather than in-clinic visits. Moreover, home visits by health care professionals shd be minimized or hold. Pnts should have at least two weeks of DX supplies with proper medications in case they have to self-isolation. If in-person visit is clinically indicated, proper infection control measures for the outpatient unit should be applied with limitation of the number of ptns seen per day. Non-urgent procedures should be postponed. The ASN has provided guidelines for nephrologists caring for hospitalized patients requiring DX for ESRD and AKI, adherence to the suggested guidelines is advised:


Ptns e COVID-19 should be co-localized on a floor or ICU, if possible. Co-localization within adjacent rooms can enable one DX nurse to simultaneously deliver DX for > one ptn. If ptn is in a negative-pressure isolation room, then one HDX nurse will need to be dedicated for the care of that ptn in a 1:1 nurse-to-ptn ratio. If possible, ptns with suspected/confirmed COVID-19 who’re not critically ill shd be dialyzed in their own isolation room rather than being transported to the in-ptn DX unit.

Video & audio streams should be used to troubleshoot alarms from outside the room to minimize the need for DX nurse or the nephrologist to enter an isolation room. CRRT is preferred among critically ill ptns in ICU who hv ESRD/AKI. Even among ptns who’re hemodynamically stable and who cd tolerate intermittent HDX (IHD), CRRT or prolonged intermittent renal replacement therapy (PIRRT), also called sustained low-efficiency DX (SLED), should be performed instead, depending upon machine & staffing availability. As CRRT or PIRRT can be managed without 1:1 HDX support. This would potentially help decrease wastage of personal protective equipment and limit exposure among HDX nurses. With CRRT capacity overwhelming, CRRT machines can be used to deliver prolonged intermittent ttt (eg, 10 hs rather than continuous) with higher flow rates (eg, 40-50 mL/kg/h). This will enable CRRT machine to be more available for care of another ptn after terminal dysinfection. If available, HDX or CRRT machines are scarce, clinicians may need to consider ttt of AKI with PD. Ptns with suspected/confirmed COVID-19 who develop AKI, and an emphasis should be placed on optimizing volume status to exclude and ttt pre-renal (functional) AKI while avoiding hypervolemia, wch may worsen ptn’s respiratory status. Ptns with AKI with no need for DX should be managed on a limited contact bases. Physical evaluation and U/S studies should be coordinated e primary/consulting teams to minimize contact, as much as possible. Ptns receiving ACEi/ARBs) should continue their therapy (unless there’s a contra-indication e.g. hyperkalemia or hypotension). There’s no evidence that stopping ACEi/ARBs limit the severity of COVID-19. Pts e stage 4/5 CKD who’re referred for DX access placement should undergo their procedures as planned (not hv their planned procedure deferred).  

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