HEAMODIALYSIS

Q.581. What is the effect of uremia on homocysteine levels?

 

 HEAMODIALYSIS

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.581. What is the effect of uremia on homocysteine levels?

A. Hyperhomocystenemia is universal in ESRD. It’s independent risk f. in a. &v. thrombosis & CVS deaths. It can cause ➤endothelial dysfunction thr. N.O. inactiveation. ttt: No beneficial evidence of vit. B6,12, folic a.- despite improvement in endothelial function é Folc a., independent effect fr. dcr. in homocysteine level.

Q.582. How to do thromboprophylaxis in uremic patients?   ☂

A. Most hospitalized ptn. hv additional f. for VTE(old age, obesity, immobility). One 1/4^th: deep veins ➤P.E.. So, LMWH Safely used in R.I. ptn, but not in ch. base. If heparin C.I.,deterrent  stocking cn be used unless PVD is present .

Q.583. What are the suggested investigations for a suspected case of VTE?

A. Clinical probability of VTE shd be estimated 1^st, then diagnostic tests cn employed safely & cost-effectively. Scoring system- esp. Wells Score- can be employed. D Dimers (fibrin breakdown products)➤highly sensitive to Ac.  thrombus formation. So, ptn. é low probability score, a –ve D Dimers can EXCLUDE Ac. thrombosis. However their accumulation in R.F., make them less helpful that imaging (Doppler) would be mandatory.

Q.584. What are the recommendations for anticoagulant use in renal impairment?

A. All ptn commencing anticoagulant thpy shd hv their kid. function evaluated:

I. Heparin: If Kid. function is N., LMWH is preferred for VTE ttt. (long ½ life & once/d.). In R.I.,dose reduction is needed due to drug accumulation & other f. Xa. inhibitors(e.g. Fondaparinux) ➤ Risk of bleeding. Still unfractionated heparin (UFH) remains the preferred anticoagulant despite risk of bleeding. 5% of UFH ptn., especially bovine heparin dev. sev. immune mediated reaction➤ increase plt., endothelial activation & fatal thrombosis. HIT➤0-12%. Clotting in extracorporeal system or site of vascular access, skin necrosis, cutaneous allergy or Ac systemic reactions. Thrombocytopenia occ. é 5-10 % of cases due to “immune mediated” etiology, with rapid onset occur é previous exposure (last 3 m.) to heparin. Dgx can be made by: [Clinical probability score, serology or functional (serotonin release, gold std. but not practical) assay]. Unfractionated heparin conventionally used in HDX. There’s now evidence of safety & efficacy of LMWH, given as single👆 bolus in arterial line☜ at beginning of DX. Adv.:{Less: bleeding, HIT, Osteoporosis&better uremic dyslipidemia}.

II. Warfarin: metabolized éliver &doesn’t accumulate in renal dis.. It’s ass. é risk of bleeding in HDX. To monitorINR, take care of heparin contamination.

- The anti-Xa level of:  0.4 iu/mL at3 h. post DX, appear to be Optimal.

Q.585. What are the recommendations for antiplatelet use in renal impairment?

A. (1) Asprin: hs the foll. effects:

1)             Anticoagulant.

2)             Aniinflammatory.

3)             Fibrinolysis. 

4)             Cyclo-oxygenase–independent Plt. inhibition.

5)             Cyclo-oxygenase modification➤irreversible defect in Thromboxane synth.➤Plt. dysfction.

- As CVS risk is high in ESRD, Aspirin benefit is undoubted, keeping the risk of uremic bleeding under control by suitable measure like keeping Hct to be steady at 30%. Aspirin cn improve graft function & survival, as the pathogenesis of allograft Rj has common features with atherosclerosis.

(2) Clopidogrel:blocksADP pathway➤its amplifying effect on Plt. activation (Permanent). Using Aspirin+Clopidogrel, to keep access patency➤Risky bleeding.

(3) Glycoprotein IIb/IIIa inhibitors(GPIs): block binding of fibrinogen to active-ted Plt. GP receptors➤prevent Plt. thrombi formation. They’re adjunctive therapy for non-ST rise Ac. coronary syndrome & essential in PTCA:➤peri-inerventional thrombotic comp., but é 🠉 risk of bleeding, which’s highest in CKD. PT, aPTT, Hct, HB, all shd be monitored. As GPIs cleared by Kid.➤dose é R.I. Tirofiban should🠉 50%  é GFR <30 ml/min. Avoid👆 eptifibatide é GFR <30 ml/min.No dose reduction é abciximab, although it’s C.I. in DX or severe R.I..

Generally, during COVID-19 pandemic, ptns receiving home DX should have 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 hv 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).