Agentic AI RAG · Clinical Decision Flow · Nephrology

CKD Dialysis Initiation
Decision Framework

Evidence-based clinical decision support integrating KDIGO 2022, ERA-EDTA 2023, IDEAL Trial, and KDOQI Vascular Access guidelines with pre-dialysis workup, medication safety, and differential diagnosis modules.

● KDIGO 2022 Update ● ERA-EDTA 2023 ● IDEAL Trial ● KDOQI Vascular Access 2019 ● Emergency Criteria

Dialysis Initiation Decision Flow

Step-by-step clinical pathway from CKD staging to modality selection, grounded in KDIGO 2022 and ERA-EDTA 2023. Includes IDEAL Trial evidence for timing of elective initiation.

⚙ CKD-EPI 2021 eGFR Calculator (Race-Free Equation)
mL/min/1.73 m²
G1 ≥90
G2 60–89
G3 30–59
G4 15–29
G5 <15
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Entry Point
CKD Patient Assessment — Staging & Trajectory
Determine CKD stage using CKD-EPI 2021 eGFR (race-free) + urine ACR. Assess trajectory: rate of eGFR decline over ≥3 months. Document modifying factors: diabetes, hypertension, proteinuria, AKI history.
KDIGO 2022 §2.1 CKD-EPI 2021 — Inker et al. NEJM
KDIGO Staging →
⚡ Emergency Screen — KDIGO 2022 §4 + ERA-EDTA 2023
Absolute Indications for Urgent Dialysis Initiation
Screen for any of the following — presence of any one criterion mandates immediate initiation regardless of eGFR:

Uraemia symptomatic: encephalopathy, seizures, pericarditis, uremic bleeding  |  Acidosis: pH <7.1 or HCO₃⁻ <12 mEq/L refractory to medical Rx  |  Electrolyte: K⁺ >6.5 mEq/L or EKG changes  |  Overload: pulmonary oedema refractory to diuretics  |  Intoxication: dialysable toxin (methanol, lithium, salicylate)
KDIGO 2022 Emergency Triggers ERA-EDTA 2023 §3.2
If NO emergency criteria →
Decision Node
Is eGFR ≤ 15 mL/min/1.73 m² OR rapid decline (>5 mL/min/yr)?
YES — Initiation Zone
KDIGO G5 / Pre-ESRD
Proceed to Elective Dialysis Planning
IDEAL Trial: no survival benefit to early initiation (eGFR 10–14) vs. late (eGFR 5–7). Initiate based on symptoms + clinical judgement, not eGFR alone. Target: symptom burden, nutritional status, volume status.
IDEAL Trial — Cooper et al. NEJM 2010 ERA-EDTA 2023 §4.1
NO — Monitoring Zone
CKD G3b–G4
Optimise Conservative Management + Prepare
Intensify CKD retardation: RAAS blockade, SGLT2i (if eGFR >20), blood pressure to <130/80 mmHg. Refer to nephrology if not already. Begin patient education on RRT modalities. Nephrology referral: eGFR <30 or rapid decline.
DAPA-CKD — Heerspink NEJM 2020 KDIGO 2022 §5
Elective initiation path →
Symptom Assessment — IDEAL Trial Criteria
Symptomatic uraemia OR clinical deterioration despite optimised conservative Rx?
YES — Initiate
Symptom-Driven Initiation
Symptoms mandating initiation
Uraemic symptoms: nausea, vomiting, anorexia, weight loss, pruritus, encephalopathy  |  Volume: resistant oedema, cardiac decompensation  |  Metabolic: progressive acidosis, hyperkalaemia unresponsive to medical Rx  |  Nutritional: unintentional weight loss >10%, serum albumin <3.5 g/dL
IDEAL Trial — Cooper 2010 KDIGO 2022 §4.2
NO — Continue Conservative
Pre-emptive Planning
Watchful Waiting with 4–8 weekly review
Continue CKD management. Monitor eGFR, electrolytes, nutritional parameters monthly. Initiate vascular access planning if eGFR <20 (see Vascular Access tab). Patient choice and shared decision-making is central. Consider peritoneal dialysis or home HD.
ERA-EDTA 2023 §4.3
Initiating → Modality Selection
Modality Selection — Shared Decision Making
Select RRT Modality Based on Clinical + Patient Factors
Preferred (If feasible)
Haemodialysis (HD)
In-centre or home HD. Requires AVF (preferred) or AVG. Avoid CVC for long-term HD — associated with ×3 higher infection risk and mortality. Initiate AVF referral ≥6 months before anticipated start.
KDOQI VA 2019 ERA-EDTA 2023
Patient-Centred Choice
Peritoneal Dialysis (PD)
Home-based. CAPD or APD. Preferred in: preserved residual renal function, young patients, remote geography, diabetic patients. Contraindicated: abdominal adhesions, hernia, no caregiver support.
KDIGO 2022 §5.1
Acute/Bridge
CRRT / SLED
For haemodynamically unstable patients in ICU. CRRT preferred over IHD in AKI-on-CKD with vasopressor dependency. SLED as intermediate modality. Transition to IHD when stable.
KDIGO AKI 2012 §5.3
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IDEAL Trial Key Finding
The IDEAL RCT (n=828, Cooper et al. NEJM 2010) found no significant difference in survival or quality of life between early (eGFR 10–14) vs. late (eGFR 5–7) initiation of dialysis. The current recommendation is symptom-guided initiation, avoiding automatic eGFR-based triggers for elective dialysis start.

Pre-Dialysis Workup Checklist

Comprehensive investigations and interventions required before dialysis initiation. Click items to mark as completed. Adapted from KDIGO 2022 pre-dialysis care standards and ERA-EDTA 2023.

Emergency — Complete within 4 hours if urgent dialysis
U&E, VBG/ABG, 12-lead ECG, portable CXR, bedside weight, IV access × 2, anaesthesia/critical care alert if HD planned emergently.
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Haematology & Iron Studies

FBC / CBC with differentialAnaemia of CKD staging; baseline pre-ESA
Hb target 10–12 g/dL
Serum Ferritin & Transferrin SaturationIron deficiency screen before ESA therapy
Ferritin >200; TSAT >20%
Reticulocyte count & reticulocyte HbFunctional iron deficiency assessment
Blood film morphologyExclude haemolysis, microangiopathy
Coagulation — PT, APTT, fibrinogenBaseline before AV fistula creation or CVC insertion
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Biochemistry & Electrolytes

U&E: Na, K, Cl, HCO₃, Urea, CreatinineeGFR (CKD-EPI 2021), acidosis assessment
K⁺ >5.5 = urgent
Venous blood gas (VBG)pH, pCO₂, HCO₃, lactate — metabolic acidosis severity
pH <7.2 = urgent
Calcium, Phosphate, MagnesiumCKD-MBD assessment; HD prescription planning
PO₄ >5.5 mg/dL
PTH (intact/biointact), Vitamin D 25-OHSecondary hyperparathyroidism staging
Uric acid, LDH, haptoglobinExclude haemolysis, gout exacerbation
24h Urine protein or spot ACRProteinuria quantification — KDIGO staging
ACR >300 = high risk
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Liver Function & Nutrition

LFT: ALT, AST, GGT, Alk Phos, BilirubinHepatic comorbidity; hepatitis serology baseline
Serum Albumin & Pre-albuminNutritional status — <3.5 g/dL indicates malnutrition risk
Alb <3.5 = high risk
Lipid panel: TC, LDL, HDL, TGCardiovascular risk baseline
HbA1c (if diabetic)Glycaemic control assessment (note: unreliable in severe anaemia)
Target HbA1c 6.5–8%
Nutritional screening (MIS or SGA)Malnutrition Inflammation Score baseline
Fasting glucose & Insulin (HOMA-IR)Insulin resistance in CKD-metabolic syndrome
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Serology & Infection Screen

Hepatitis B sAg, sAb, core Ab (HBcAb)Mandatory pre-HD; isolation bay planning; vaccination status
Hepatitis C Ab + HCV RNA (if Ab+)Identify for treatment pre-dialysis if possible (DAA therapy)
HIV 1/2 Ag/Ab combination assayInfection control planning; antiretroviral renal dosing
SARS-CoV-2 status (institutional protocol)Dialysis unit isolation protocol compliance
Quantiferon-TB (or TST)Latent TB screen — immunosuppressed population
Nasal MRSA swab (pre-AVF / CVC)Decolonisation protocol if positive (mupirocin × 5d)
Blood culture × 2 if febrile or septicBefore empiric antibiotics — mandatory
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Cardiovascular Workup

12-lead ECGHyperkalaemia changes, LVH, arrhythmia, ischaemia
Mandatory always
Echocardiogram (transthoracic)LVH, wall motion, EF, pericardial effusion — uraemic pericarditis
Troponin I/T (high-sensitivity)Chronically elevated in CKD — baseline essential for future comparison
NT-proBNP or BNPVolume overload assessment; cardiac failure staging
Chest X-ray (erect PA if possible)Pulmonary congestion, cardiomegaly, pleural effusion
Holter / prolonged cardiac monitoring (if indicated)Atrial fibrillation, dialysis-related arrhythmia risk
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Vascular Access & Miscellaneous

Upper limb vein mapping (duplex USS)Basilic / cephalic vein diameter ≥2.5 mm for AVF suitability
KDOQI VA 2019
Arterial assessment (radial/brachial pulse, Allen test)Arterial patency for radio-cephalic or brachio-cephalic AVF
Surgical vascular access referral (≥6 months pre-HD)AVF maturation requires 6–8 weeks minimum post-creation
Hepatitis B vaccination status + booster if needed3-dose series or 2-dose Heplisav-B; higher-dose regimen for CKD
Vaccination: Pneumococcal, Influenza, COVID-19Immunisation before immunosuppression or dialysis commencement
Renal Dietitian referral + low K/P diet counsellingPre-dialysis dietary optimisation; phosphate binder education
Psychosocial assessment + RRT modality educationShared decision-making — HD vs PD vs conservative care
Advance care planning documentationGoals of care, ceiling of treatment, organ donation wishes
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Checklist Progress
Click items above to track completion. All items should be completed before elective dialysis initiation. Items marked red-threshold require immediate clinical action if outside target range.

Medication Safety & Renal Dose Adjustment

Pre-dialysis medication reconciliation with renal dose adjustment guidance. Adjusted for eGFR thresholds per BNF/Micromedex/KDIGO 2022 pharmacotherapy recommendations.

STOP Immediately — Pre-Dialysis
Metformin (if eGFR <30), NSAIDs/COX-2 inhibitors, ACE inhibitors on day of HD (volume-dependent), nephrotoxic antibiotics (gentamicin without level monitoring), oral anticoagulants without renal dose adjustment.
Drug / Class Action at eGFR Recommendation Evidence Status
Metformin
Biguanide
eGFR <45: reduce dose
eGFR <30: STOP
Lactic acidosis risk in renal impairment. Withhold if AKI or contrast. Discontinue permanently at eGFR <30. 1A KDIGO STOP <30
SGLT2 Inhibitors
Dapagliflozin, Empagliflozin
eGFR <25: glycaemic benefit lost; eGFR <20: STOP for glycaemia (renoprotective benefit may persist per DAPA-CKD) Continue for CKD progression retardation down to eGFR ≥20 (DAPA-CKD trial). Discontinue before HD initiation — dehydration/DKA risk. 1B DAPA-CKD Reduce/Stop
ACE Inhibitors / ARBs
Ramipril, Losartan
Continue through CKD if tolerated. Withhold on HD days if volume-depleted. Stop if K⁺ >6.0 mEq/L unresponsive to measures. Continue for renoprotection and proteinuria reduction. Monitor creatinine (acceptable rise <30% from baseline). Avoid in bilateral RAS. 1A KDIGO 2022 Monitor
NSAIDs / COX-2 inhibitors
Ibuprofen, Celecoxib
All eGFR levels: avoid; esp. eGFR <30 Contraindicated in CKD G3b+. Accelerate eGFR decline, cause AKI via NSAID-mediated afferent arteriolar constriction. Substitute paracetamol. 1A STOP
Gabapentin / Pregabalin
Neuropathic pain, uraemic itch
eGFR 30–60: reduce to 50% dose
eGFR <30: 25% dose
Dialysis: dose post-HD session
Renally cleared; accumulation causes somnolence, confusion. In HD: significant dialysis clearance — dose after session (100–300 mg post-HD). 2B Dose Reduce
Low Molecular Weight Heparin
Enoxaparin, Dalteparin
eGFR <30: accumulation risk — anti-Xa monitoring or switch to UFH Use UFH (unfractionated) in eGFR <30 or active HD. If LMWH required: anti-Xa monitoring (target 0.5–1.0 IU/mL), dose reduction (enoxaparin 1 mg/kg once daily vs BD). 1B Caution
Direct Oral Anticoagulants
Apixaban, Rivaroxaban, Dabigatran
Dabigatran: STOP eGFR <30 (dialysable)
Apixaban: use 2.5 mg BD if ≥2 of: Cr>1.5, age≥80, wt≤60 kg; STOP on HD
Rivaroxaban: avoid eGFR <15
Warfarin is preferred in CKD G4–5 AF (lower stroke risk reduction with DOACs in dialysis patients per observational data). Individual risk-benefit with haematology. 2B Caution/Adjust
Statins
Atorvastatin, Rosuvastatin
Continue through all CKD stages. Do NOT initiate in HD patients (4D, AURORA trials — no benefit, possible harm). Continue if already established in dialysis patients. Do not start de novo in prevalent HD (KDIGO Lipids 2013). Atorvastatin preferred (mainly hepatic clearance). 1A KDIGO Lipids Continue (pre-HD)
Allopurinol
Uric acid reduction
eGFR 30–60: max 200 mg/day
eGFR <30: max 100 mg/day
HD: dose post-dialysis
Accumulation of active metabolite oxipurinol causes severe toxicity (bone marrow suppression, Stevens-Johnson). Monitor allopurinol level if <eGFR 30. 2C Dose Reduce
Phosphate Binders
Calcium carbonate, Sevelamer, Lanthanum
Initiate when PO₄ >4.5 mg/dL despite dietary restriction Non-calcium binders (sevelamer, lanthanum) preferred in dialysis — avoid calcium loading. Calcium carbonate acceptable pre-dialysis if serum Ca normal. Take with meals. 1B KDIGO MBD Initiate if indicated
ESA — Erythropoiesis Stimulating Agents
Darbepoetin alfa, Epoetin alfa
Initiate when Hb <10 g/dL after iron repletion (TSAT >20%, ferritin >100) Target Hb 10–12 g/dL. Avoid Hb >13 g/dL (CHOIR trial: increased CV events). Reduce or withhold if Hb rising >1 g/dL per 2 weeks or Hb >12. 1A KDIGO Anaemia Monitor closely
Potassium Binders
Patiromer, Sodium Zirconium Cyclosilicate
Initiate for persistent K⁺ >5.0 mEq/L to maintain RAAS therapy Novel agents enable continuation of ACEi/ARB in hyperkalaemia-prone CKD patients. Patiromer: 8.4 g once daily with food. SZC: 10 g TDS × 48h then 5 g/day maintenance. 1B Initiate if K⁺ raised
Aminoglycosides
Gentamicin, Tobramycin
Nephrotoxic — avoid in CKD G3b+. If essential: single-dose, level-guided, with nephrology input If unavoidable in life-threatening infection: extended-interval dosing, trough <1 mg/L. Monitor renal function daily. Dialysis patients: dose post-HD session; obtain pre-HD trough level. 1A Avoid / Level-guide
Medication Reconciliation Principle
All patients transitioning to dialysis require a full medication reconciliation by a renal pharmacist. Particular attention to: drugs requiring post-HD supplemental dosing (gabapentin, acyclovir, vancomycin), drugs with altered protein binding in uraemia, and drugs contraindicated in PD (icodextrin interactions with amylase-based glucose monitors).

Differential Diagnosis Support

Common and important differential diagnoses for acute or subacute deterioration in eGFR in a CKD patient. Probability estimates are contextual — adjust based on clinical history, urinalysis, and imaging.

AKI-on-CKD — First Exclude Reversible Causes
Before accepting progressive CKD as the aetiology of eGFR decline, systematically exclude: obstruction (obstructive uropathy), volume depletion, nephrotoxins, renovascular disease, and intrinsic AKI causes. Every unexplained eGFR drop warrants urine dipstick, microscopy, and renal ultrasound as minimum workup.
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Pre-renal / Haemodynamic

Common
Volume depletion (over-diuresis)
85%
Cardiac failure / cardiorenal
70%
Sepsis / distributive shock
60%
Hepatorenal syndrome
25%
Key: BUN:Cr ratio >20:1, fractional Na excretion <1%, orthostatic hypotension, muddy brown casts absent.

Post-renal / Obstructive

Must Exclude
BPH / bladder outlet obstruction
70%
Ureteric calculi (bilateral / solitary kidney)
40%
Malignancy — extrinsic compression
30%
Retroperitoneal fibrosis
10%
Key: Renal USS — hydronephrosis. Bladder residual volume >300 mL. Consider CT KUB if USS non-diagnostic. Catheterise if outlet obstruction suspected.

Nephrotoxin-Induced AKI

High Risk in CKD
NSAIDs / COX-2 inhibitors
80%
Contrast nephropathy (CI-AKI)
65%
Aminoglycosides
55%
Calcineurin inhibitors (tacrolimus, ciclosporin)
45%
Herbal / complementary medicines
30%
Full medication history including OTC, herbal, supplements. NSAID mechanism: afferent arteriolar constriction → acute tubular ischaemia on background CKD.

Renovascular Disease

Under-diagnosed
Atherosclerotic renal artery stenosis
60%
ACEi-induced in bilateral RAS
45%
Cholesterol embolisation
20%
Fibromuscular dysplasia (younger patients)
10%
Clues: flash pulmonary oedema, refractory hypertension, asymmetric kidneys on USS, eGFR drop >30% on ACEi initiation. Renal duplex or CT angiography for evaluation.

Intrinsic Renal / Glomerular

Biopsy May Be Needed
Rapidly progressive GN (RPGN)
75%
IgA nephropathy exacerbation
60%
Diabetic nephropathy (DKD) progression
55%
Membranous nephropathy (de novo)
30%
Vasculitis (ANCA, anti-GBM)
20%
Red cell casts / nephritic sediment = glomerular origin. Immunology: ANCA, anti-GBM, ANA, complement (C3/C4), anti-PLA2R. Biopsy if aetiology unclear and clinically safe.

Metabolic / Systemic

Reversible if Caught Early
Hypercalcaemia (myeloma, sarcoid, PTH)
50%
Acute uric acid nephropathy
35%
Light chain nephropathy (myeloma cast)
25%
Thrombotic microangiopathy (TMA)
15%
Workup: SPEP, serum free light chains, BJP urine, blood film (schistocytes in TMA), ADAMTS13 (TTP). Calcium and uric acid levels. Bone marrow biopsy if myeloma suspected.
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Systematic DDx Approach — AKI-on-CKD Workup
Step 1: Urine dipstick + microscopy (sediment analysis) → Step 2: Urine Na, osmolality, FENa → Step 3: Renal USS (obstruction, kidneys size/symmetry) → Step 4: Medication review for nephrotoxins → Step 5: Immunology screen if glomerular suspected → Step 6: Renal biopsy if aetiology unclear and clinically safe (avoid if small <8 cm echogenic kidneys — chronic irreversible disease likely).

Vascular Access Planning

Sequential decision pathway for HD vascular access — KDOQI Vascular Access 2019 guidelines with ERA-EDTA 2023 supplementary recommendations. Fistula First principle remains the gold standard.

KDOQI 2019 — Fistula First Principle
AVF is the preferred permanent access for HD. Access hierarchy: AVF (radiocephalic → brachiocephalic → transposed brachiobasilic) → AVG → Tunnelled CVC (bridge only). Non-tunnelled CVC: emergency only, maximum 7 days.
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AVF

1st Choice — Autologous AV Fistula (AVF)

Radiocephalic (wrist, RC-AVF) is the preferred first attempt — lowest thrombosis, best long-term patency. If unsuitable (vein <2 mm, arterial disease): brachiocephalic (BC-AVF) or transposed brachiobasilic (BB-AVF). Requires vein diameter ≥2.5 mm and radial artery diameter ≥2.0 mm on duplex mapping.

Maturation criteria (KDOQI "Rule of 6s"): Diameter ≥6 mm, depth ≤6 mm from skin, flow ≥600 mL/min at 6 weeks post-creation.

⏱ Refer ≥6 months before anticipated HD start · Maturation 6–12 weeks · Primary failure rate: 20–40%

AVG

2nd Choice — Prosthetic AV Graft (AVG)

When autologous veins are unsuitable or primary AVF has failed. ePTFE or PTFE graft — brachio-antecubital most common. Earlier cannulation possible (2–3 weeks for standard PTFE, 24–72 hours for early cannulation grafts). Higher thrombosis and infection rates vs. AVF. Surveillance programme essential (monthly flow monitoring).

⏱ Cannulation 2–6 weeks (standard) or 24–72h (Acuseal/Flixene) · Suitable for patients with poor vein anatomy

CVC

Bridge / Emergency — Tunnelled Cuffed CVC (TCC)

Right internal jugular vein is the preferred site. Subclavian vein must be avoided — high risk of central vein stenosis that precludes future ipsilateral AVF/AVG. Femoral CVC only for short-term bridge in emergencies with no upper limb access. TCC carries ×3 higher mortality risk than AVF (infection, thrombosis, bacteraemia — Staphylococcus aureus most common pathogen).

⚠ Non-tunnelled CVC: maximum 7 days only. Convert to TCC or functioning AVF/AVG as soon as possible.

⏱ Right IJV preferred · Subclavian CONTRAINDICATED · Lock with citrate or heparin between sessions

PD

Alternative — Peritoneal Dialysis Catheter

For patients choosing PD as modality. Tenckhoff catheter — laparoscopic placement preferred (lower malposition rates). Break-in period: 2 weeks minimum (urgent start PD possible with low-volume supine exchanges after 1–2 days in experienced centres). Patient suitability: intact peritoneum, adequate home environment, manual dexterity or trained caregiver.

Absolute PD contraindications: extensive abdominal adhesions, active abdominal infection/IBD, large abdominal hernia (repair first), no peritoneal access possible.

⏱ Insert ≥2 weeks before PD start · Allows flush and leak testing · Urgent start possible in experienced centres

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Access Selection Decision Matrix

Clinical Factor AVF AVG TCC PD Catheter
Adequate vein (≥2.5 mm duplex)✓ PreferredAlternativeNot indicatedNot applicable
Poor peripheral veinsNot feasible✓ PreferredBridgeConsider PD
Imminent HD need (<1 week)Not readyEarly cannulation graft✓ UseUrgent start PD
Active systemic infectionDeferDeferCautionContraindicated
Patient preference — home therapyHome HD possibleLess suitableNot suitable✓ Ideal
Diabetic + severe peripheral vascular diseaseMay have arterial issues✓ PreferredBridgeConsider
Previous failed access (ipsilateral)Contralateral AVF✓ PreferredBridgeConsider PD
Subclavian Vein — Absolute Contraindication for HD Access
Subclavian vein catheterisation carries a 40–50% risk of central vein stenosis or occlusion, which permanently precludes ipsilateral upper limb arteriovenous access. KDOQI 2019 recommends the subclavian route is never used for HD access in patients with existing or potential future upper limb fistulas. Right internal jugular vein is the universal first choice.