337.1 🎓 醫孞生版

337.1.0.1 📌 䞀頁重點

337.1.0.1.1 Dialysis Indications + Timing

337.1.1 ESKD Definition

  • eGFR < 15 mL/min/1.73 m² OR
  • Need for RRT based on symptoms

337.1.2 Indications for Initiation

  • Uremic symptoms (encephalopathy, pericarditis, bleeding, persistent nausea/vomiting, malnutrition)
  • Hyperkalemia refractory to medical management
  • Acidosis refractory
  • Volume overload refractory to diuretics
  • eGFR < 10 (some advocate)

337.1.3 Timing of Initiation

  • IDEAL trial (2010): early (eGFR 10-14) vs late (5-7) → no mortality benefit
  • Practice: defer until symptomatic in most
  • Some advocate ≀ 10 even if asymptomatic
  • Patient-centered + multidisciplinary
337.1.3.0.1 Hemodialysis (HD)

337.1.4 Principles

  • Blood through artificial kidney (dialyzer)
  • Removes solutes (urea, K, etc.) by diffusion
  • Removes water by ultrafiltration (pressure gradient)
  • 4-hour sessions, 3x/week (standard)

337.1.5 Setup

  • Blood pump 200-500 mL/min
  • Dialysate flow ~ 500-800 mL/min
  • Countercurrent flow
  • Various membrane types

337.1.6 Vascular Access — “Fistula First” + “Catheter Last”

Arteriovenous (AV) Fistula (Gold Standard): - Surgically created connection: radial artery + cephalic vein (radiocephalic), brachial artery + cephalic vein (brachiocephalic) - Created 3-6 months before HD start - Best long-term patency - Lower infection rate - Maturation 6-12 weeks

AV Graft: - Synthetic material (PTFE) - Used when fistula not feasible - Earlier usable (2-4 weeks) - Higher complication rate

Central Venous Catheter (CVC): - Tunneled (long-term): PermCath - Non-tunneled (acute) - Highest infection + thrombosis rates - Use only as last resort or temporary

KDOQI 2019 Vein Preservation: - Avoid PICCs, subclavian access - Preserve veins (especially non-dominant arm) - Earlier referral for fistula

337.1.7 Frequency Options

In-Center Conventional HD: - 3x/week, 4 hours - Most common

Daily HD: - 5-6x/week, 2-3 hours - Better outcomes (FHN trial) - Home or in-center

Nocturnal HD (Home): - 5-6 nights/week, 6-8 hours - Slow, gentle ultrafiltration - Better BP, electrolyte control - Lifestyle benefit

Home HD: - Independence - Multiple regimens

337.1.8 Complications

Intradialytic: - Hypotension (most common — > 20%) — volume removal, autonomic dysfunction - Cramps - Nausea, vomiting - Headache - Pruritus - Chest pain - Air embolism - Disequilibrium syndrome (especially first sessions) - Hemolysis (rare) - Allergic reactions to dialyzer

Vascular Access: - Thrombosis (most common AV access complication) - Infection (especially CVC; sepsis 10x higher with CVC vs fistula) - Stenosis - Aneurysm / pseudoaneurysm - Steal syndrome (distal ischemia) - Venous hypertension - Cardiac failure (high-output)

Long-Term: - Bone disease - Anemia - Cardiovascular (most common cause of death) - Infection - Cognitive decline

337.1.9 Specific Issues

Intradialytic Hypotension: - Reduce UF rate - Cool dialysate - Sodium modeling - Midodrine prophylactic

Cramps: - Reduce UF - Stretching - Quinine controversial

Pruritus: - Treat hyperphosphatemia - Difelikefalin (NEW, Kappa-opioid receptor agonist; FDA 2021) - Antihistamines, gabapentin

337.1.9.0.1 Peritoneal Dialysis (PD)

337.1.10 Principles

  • Peritoneum as membrane
  • Dialysate dwell in peritoneal cavity
  • Diffusion + osmotic ultrafiltration (via glucose, icodextrin)

337.1.11 Catheter

  • Tenckhoff catheter (most common)
  • Surgically placed (laparoscopic or open)
  • Tunneled subcutaneous
  • Exit site care critical

337.1.12 Modalities

Continuous Ambulatory PD (CAPD): - Manual exchanges - 4-5 exchanges per day - Daytime activity

Automated PD (APD) (most common): - Cycler machine at night - Nocturnal exchanges - Daytime free or one daytime dwell

337.1.13 Solutions

  • Glucose-based: 1.5%, 2.5%, 4.25%
  • Icodextrin (Extraneal): for long dwells (8+ hours); maltose polymer, less glucose absorption
  • Bicarbonate-based (Physioneal): biocompatible
  • Amino acid-based (Nutrineal): for nutrition support

337.1.14 Complications

Peritonitis (Cardinal): - Cloudy effluent + abdominal pain - > 100 WBC/ÎŒL with > 50% neutrophils - Pathogens: S. epidermidis (most common, contamination), S. aureus, GNR, fungi (rare but severe) - Treatment: intraperitoneal antibiotics (gentamicin + cefazolin or vancomycin; tailored) - Catheter removal if fungal, refractory, severe - Prevention: aseptic technique, mupirocin prophylaxis

Exit Site / Tunnel Infection: - S. aureus most common - Erythema, drainage - Treatment: oral antibiotics; catheter exchange if refractory

Mechanical: - Catheter malfunction (constipation, kinks, omental wrapping) - Hernia (abdominal pressure) - Leak (pleural, scrotal, genital) - Hydrothorax

Metabolic: - Hyperglycemia (glucose absorption) - Weight gain - Hyperlipidemia - Hypokalemia (some)

Membrane Failure: - Long-term peritoneal damage - Ultrafiltration failure - Encapsulating peritoneal sclerosis (rare, severe)

337.1.15 Modality Choice

HD Considerations: - Easier for severely sick or non-compliant - Vascular access available - Lifestyle (in-center vs home) - Hemodynamic instability

PD Considerations: - Better preserved residual renal function (first 1-2 years) - Avoid vascular access issues - Better for cardiac issues (less hemodynamic stress) - Lifestyle flexibility - Self-care + training required - Limited by peritoneal membrane lifespan - Avoided in severe abdominal pathology

337.1.16 Patient Selection

HD Preferred If: - Inability to do PD (motor, vision, cognition) - Severe abdominal disease - Massive obesity (some) - Multiple abdominal surgeries - Personal preference

PD Preferred If: - Need cardiac stability - Travel flexibility important - Working - Severe CV / poor vasc access - Pediatric

337.1.17 Outcomes

  • Similar survival
  • PD: better first 1-2 years
  • HD: long-term benefits in some
  • Modality switching common
337.1.17.0.1 Adequacy + Dialysis Dose

Kt/V: - HD: per session, target ≥ 1.2 (single pool) or weekly ≥ 1.8 - PD: weekly Kt/V (urea) ≥ 1.7

URR (Urea Reduction Ratio) (HD): - Pre-HD urea minus post-HD / pre-HD - > 65%

337.1.17.0.2 Mortality + Other Outcomes

337.1.18 Mortality

  • ~ 20-25% annual mortality (US)
  • Cardiovascular leading cause
  • Infection 2nd
  • Cancer + others

337.1.19 Quality of Life

  • Variable
  • Better with home modalities
  • Renal transplant best QoL

337.1.20 Hospitalization

  • Common
  • Access complications, infection, CV events
  • Prevention focus

337.1.20.1 🩺 床邊速查

  • HD: 3x/week 4h; AV fistula gold standard
  • PD: APD (nocturnal) most common; cardinal complication = peritonitis
  • IDEAL trial 2010: defer initiation until symptomatic
  • Vascular access: fistula first, catheter last (KDOQI 2019)
  • Intradialytic hypotension: reduce UF + cool dialysate
  • PD peritonitis: cloudy effluent + abd pain; intraperitoneal antibiotics
  • Difelikefalin: kappa-opioid for HD pruritus (FDA 2021)
  • Mortality: 20-25%/year; CV top cause