Hemodialysis & CRRT Nursing Guide 2026
⚕️ Medical Disclaimer: This content is for educational purposes only and is intended for licensed healthcare professionals. It does not constitute medical advice and should not replace clinical judgment, facility protocols, or physician orders. Always verify medications, doses, and procedures with your institution's guidelines.
Part of the ICU Devices Hub — browse every related guide in one place.
This article was created with AI assistance.
Hemodialysis vs CRRT comparison, AV fistula assessment, dialysis catheter care, CRRT modes, anticoagulation, troubleshooting alarms, and nursing priorities for renal replacement therapy.
1. Hemodialysis vs. CRRT Comparison
| Feature | Intermittent Hemodialysis (IHD) | CRRT (Continuous Renal Replacement Therapy) |
|---|
| Duration | 3–5 hours, 3× per week (outpatient) or daily (ICU) | Continuous (24 hr/day) |
| Hemodynamic tolerance | Requires hemodynamic stability | Well-tolerated in hemodynamically unstable patients |
| Fluid removal rate | Rapid (2–4 L over session) | Slow and continuous (100–300 mL/hr) |
| Solute clearance | Excellent small solute clearance | Better middle molecule clearance; slower small solute |
| Setting | Dialysis unit or ICU | ICU exclusively |
| Anticoagulation | UFH or regional citrate for session | Continuous anticoagulation required (UFH or citrate) |
| Primary indication | End-stage renal disease; stable AKI | Hemodynamically unstable AKI, fluid overload, MODS, sepsis with AKI |
2. AV Fistula and Graft Assessment
The AV fistula is the patient's lifeline — protect it at all costs.
NEVER on the fistula arm:
- Blood pressure measurements
- IV insertion or blood draws
- Tight clothing or jewelry
- Patient lying on the arm
- Tourniquet application
| Assessment | Normal Finding | Abnormal → Action |
|---|
| Thrill (vibration) | Continuous palpable vibration (buzz) over fistula | Absent thrill → clot? Notify provider immediately; may need urgent intervention |
| Bruit (auscultation) | Continuous low whooshing sound with stethoscope | Absent bruit → thrombosis; high-pitched (stenosis) → notify nephrology |
| Skin | Warm, no redness over access site | Redness, warmth, pus → infection; report and culture |
| Bleeding post-dialysis | Stops with 15–20 min of direct pressure | >20 min: hold pressure; >30 min: notify provider |
| Aneurysm | Slight bulging is common in mature fistulas | Rapidly enlarging aneurysm; thin overlying skin; report to nephrologist |
Graft vs. Fistula Differences
| Feature | AV Fistula | AV Graft |
|---|
| Material | Patient's own vein joined to artery | Synthetic (PTFE) tube connecting artery to vein |
| Maturation time | 4–6+ weeks before first use | 2–3 weeks (can use sooner) |
| Infection risk | Lower (own tissue) | Higher (synthetic material) |
| Preferred | Yes — gold standard when possible | Used when veins inadequate for fistula |
| Thrombosis risk | Lower | Higher |
3. Dialysis Catheter (Temporary Vascular Access) Care
- Tunneled (Permcath): placed in IR or OR; cuff under skin reduces infection risk; used weeks to months
- Non-tunneled (temporary): subclavian, internal jugular, or femoral; femoral highest infection risk; use ≤1 week ideally
- Sterile technique ALWAYS for catheter connections and dressing changes — dialysis catheters are NOT standard IV access
- Dressing change: q72h or when soiled, using sterile gloves + mask; chlorhexidine-based prep
- Heparin lock after each session (high-concentration heparin — usually 1000–5000 units/mL per lumen): aspirate and discard the lock before next session (do NOT flush lock in — patient will receive a bolus)
- NEVER use dialysis catheter for routine IV fluids, blood draws, or medications (except emergencies)
- Catheter malfunction: position change (deep breath, Trendelenburg, roll to side); check for kinks; notify provider if flows inadequate
4. CRRT Modes
| Mode | Full Name | Mechanism | Best For |
|---|
| CVVH | Continuous Venovenous Hemofiltration | Convection only — fluid pushed through membrane by pressure; replacement fluid added back | Fluid removal + middle molecule clearance; sepsis |
| CVVHD | Continuous Venovenous Hemodialysis | Diffusion only — dialysate flows countercurrent to blood across membrane | Small solute clearance (urea, creatinine, potassium) |
| CVVHDF | Continuous Venovenous Hemodiafiltration | Both convection AND diffusion | Maximum clearance; most commonly used in ICU |
| SCUF | Slow Continuous Ultrafiltration | Ultrafiltration only — no replacement fluid or dialysate; slow fluid removal | Fluid overload without significant uremia; CHF |
5. CRRT Key Parameters
| Parameter | Description | Typical Range/Notes |
|---|
| Blood flow rate (Qb) | Speed blood moves through circuit | 150–250 mL/min; lower than IHD to reduce hemodynamic impact |
| Effluent dose | Total volume processed per kg per hour (CVVH: replacement; CVVHD: dialysate; CVVHDF: sum) | 20–25 mL/kg/hr standard; 35 mL/kg/hr for sepsis (higher dose) |
| Net fluid removal (UFR) | Planned fluid removed per hour from patient | Physician ordered; may be 0 mL/hr (euvolemic) to 200+ mL/hr (overloaded) |
| Filter life | Time before filter clots and requires change | Goal >24 hr; <12 hr = anticoagulation concern; >72 hr = excellent |
| Replacement fluid | Fluid infused to replace ultrafiltrate removed in CVVH/CVVHDF | Pre-filter or post-filter; pre-filter dilutes blood = extends filter life; post-filter = more efficient clearance |
6. CRRT Anticoagulation
| Agent | Mechanism | Monitoring | Use When |
|---|
| UFH (Unfractionated Heparin) | Systemic anticoagulation | aPTT 45–60 sec or anti-Xa level | Most patients without bleeding risk |
| Regional Citrate | Citrate chelates calcium in circuit → anticoagulates filter; calcium replaced systemically | Ionized Ca in circuit (0.25–0.35 mmol/L); ionized Ca systemic (1.1–1.3 mmol/L) | Bleeding risk, thrombocytopenia, HIT; preferred in most ICUs |
| No anticoagulation | Frequent saline flushes | Watch filter pressures | Active hemorrhage; coagulopathic patients (INR >2.5, PLT <60k) |
Citrate toxicity (citrate accumulation, usually in liver failure): total Ca high, ionized Ca low, elevated total Ca:ionized Ca ratio >2.5; high anion gap metabolic acidosis. Treatment: stop or reduce citrate rate; increase systemic calcium replacement.
7. CRRT Alarms and Troubleshooting
| Alarm | Possible Cause | Nursing Action |
|---|
| Access pressure alarm (too negative) | Catheter kinking, malposition, clot, patient turning | Reposition patient; check for kinks; try clamping/unclamping; may need to reverse lines temporarily |
| Return pressure alarm (too high) | Filter clotting, air bubble, blood thickening downstream | Check filter age; increase anticoagulation rate; prepare for filter change |
| Air detector alarm | Air in circuit — clamp return line immediately | CLAMP RETURN LINE; do NOT return blood to patient until air is removed; notify provider |
| Blood leak alarm | Filter membrane rupture — blood in effluent | STOP CRRT; do NOT return blood; change filter; notify provider |
| Low effluent flow | Filter clotting; kinked lines | Check lines; if filter pressure rising → prepare to change circuit; document filter life |
8. Dialysis Disequilibrium Syndrome
Occurs during or immediately after first hemodialysis sessions in patients with very high BUN (>175 mg/dL).
Cause: rapid removal of urea from blood faster than from brain → osmotic gradient → cerebral edema
Symptoms: headache, nausea, confusion, seizures, coma
Prevention: shorter, slower first sessions; use CRRT in severe azotemia; gradual BUN reduction
Treatment: stop or slow dialysis; mannitol; supportive care
NCLEX High-Yield: Dialysis
- AV fistula: NEVER take BP, draw blood, or start IV on that arm
- Assess fistula: palpate for thrill (vibration); auscultate for bruit (whooshing) — absent = thrombosis emergency
- Heparin lock: aspirate and discard before using catheter — do NOT flush in
- CRRT vs IHD: CRRT for hemodynamically unstable patients; IHD for stable
- Blood leak alarm: STOP CRRT, do NOT return blood to patient
- Air detector alarm: clamp return line immediately before anything else
- Dialysis disequilibrium: rapid removal of urea → cerebral edema; headache/seizures during/after first treatment
- CRRT effluent dose: standard 20–25 mL/kg/hr; higher (35) for sepsis
- Citrate toxicity: total Ca high, ionized Ca low → occurs in liver failure (can't metabolize citrate)
Get the ICU Notebook
Free investing strategies built for nurses. One email per week, no fluff.
Yes, send it free
No spam. Unsubscribe any time.